Von: CustomerService@lifeextension.com [mailto:CustomerService@lifeextension.com]
Gesendet: Donnerstag, 5. März 2015 20:21
An: volker@vonabisw.de
Betreff: Case:[3351885] - WG: Dr. Bruce Hollis - Vitamin D Dosing Interval - it must be
daily?
Dear Volker Schendel ,
Thank you for your recent correspondence.
Life Extension certainly agrees that daily administration of vitamin D3 has the best efficacy in
maintaining levels within a narrow range, and avoiding peaks and troughs associated with
intermittent dosing.
Since vitamin D is important for a wide variety of cells in the body, it is critical to maintain
sufficient vitamin D availability. Dr. Hollis’ research seems to validate this idea.
Please keep in mind that Life Extension cannot comment on whether it is “medical
malpractice” to use a weekly dosing instead of daily supplementation. Nevertheless, we feel
that daily dosing is ideal to ensure consistent availability of vitamin D to target tissues.
Please let us know if there is anything else we can do for you. If you have any additional
questions, please e-mail us or call the advisor helpline at (800) 226-2370; international
customers dial 001-954-202-7660.
Thank you for choosing Life Extension as your trusted source of health information.
Please make sure Case:[3351885] is in the subject line of all correspondence.
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History of Vitamin D
Historical Review
Man is reported to have been aware since early antiquity of the substance we now
know as vitamin D. The first scientific description of a vitamin D-deficiency, namely
rickets, was provided in the 17th century by both Dr. Daniel Whistler (1645) and
Professor Francis Glisson (1650). The major breakthrough in understanding the
causative factors of rickets was the development in the period 1910 - 1930 of nutrition
as an experimental science and the appreciation of the existence of vitamins.
Considering the fact that now we accept that the biologically active form of vitamin D,
namely 1a,25(OH)2-vitamin D3, is a steroid hormone, it is somewhat ironic that vitamin
D, through a historical accident, became classified as a vitamin. It was in 1919/20 that
Sir Edward Mellanby, working with dogs raised exclusively indoors (in the absence of
sunlight or ultraviolet light), devised a diet that allowed him to unequivocally establish
that the bone disease, rickets was caused by a deficiency of a trace component
present in the diet. In 1921 he wrote, "The action of fats in rickets is due to a vitamin or
accessory food factor which they contain, probably identical with the fat-soluble
vitamin." Furthermore, he established that cod liver oil was an excellent antirachitic
agent.
Shortly thereafter E.V. McCollum and associates observed that by bubbling oxygen
through a preparation of the "fat-soluble vitamin" they were able to distinguish
between vitamin A ( which was inactivated) and vitamin D (which retained activity). In
1923 Goldblatt and Soames clearly identified that when a precursor of vitamin D in the
skin (7-dehydrocholesterol) was irradiated with sunlight or ultraviolet light, a
substance equivalent to the fat-soluble vitamin was produced. Hess and Weinstock
confirmed the dictum that "light equals vitamin D". They excised a small portion of
skin, irradiated it with ultraviolet light, and then fed it to groups of rachitic rats. The
skin that had been irradiated provided an absolute protection against rickets, whereas
the unirradiated skin provided no protection whatsoever; clearly, these animals were
able to produce by uv irradiation adequate quantities of "the fat-soluble vitamin",
suggesting that it was not an essential dietary trace constituent. In parallel studies,
Steenbock and Black at the Biochemistry Department of the University of Wisconsin
found that rat food which was irradiated with ultra violet light also acquired the
property of being antirachitic. However, because of the rapid rise of the science of
nutrition -- and the discovery of the families of water-soluble and fat-soluble vitamins - it rapidly became firmly established that the antirachitic factor was to be classified as
a vitamin.
The chemical structures of the vitamins D were determined in the 1930s in the
laboratory of Professor Adolf Otto Reinhold Windaus at the University of Göttingen in
Germany. Professor Windaus had some 55 doctoral and postdoctoral chemists
working on the 'vitamin D project'. Professor Windaus received a Nobel Prize in
Chemistry in 1928 for his work on sterols and their relationship to vitamins.
Vitamin D2 which could be produced by ultraviolet irradiation of ergosterol was
chemically characterized in 1932. Vitamin D3 was not chemically characterized until
1936 when it was shown to result from the ultraviolet irradiation of 7dehydrocholesterol. Virtually simultaneously, the elusive antirachitic component of
cod liver oil was shown to be identical to the newly characterized vitamin D3. These
results clearly established that the antirachitic substance vitamin D was chemically a
steroid, more specifically a seco-steroid.
Key reference citations:
Whistler, D. Morbo puerili Anglorum, quem patrio idiomate indigenae vocant The
Rickets. Lugduni Batavorum 1-13 (1645).
Glisson, F. De Rachitide sive morbo puerili, qui vulgo The Rickets diciteur, London 1416 (1650).
Glisson, F. A treatise of the rickets being a disease common to children. London 1-373
(1668).
Mellanby, E. and Cantag, M.D. Experimental investigation on rickets. Lancet 196:407412 (1919).
Mellanby, E. Experimental rickets. Medical Research (G.B.), Special Report Series
SRS-61:1-78 (1921).
Hess, A. Influence of light on the prevention of rickets. Lancet 2:1222 (1922).
McCollum, E.V., Simmonds, N., Becker, J.E. and Shipley, P.G. Studies on experimental
rickets. XXI. An experimental demonstration of the existence of a vitamin which
promotes calcium deposition. J. Biol. Chem. 53:293-312 (1922).
Goldblatt, H. and Soames, K.N. A study of rats on a normal diet irradiated daily by the
mercury vapor quartz lamp or kept in darkness. Biochem. J. 17:294-297 (1923).
Steenbock, H. and Nelson, M. T. Fat-soluble vitamins. XIX. The induction of calcifying
properties in a rickets-producing ration by radiant energy. Methods Enzymol. 62:209216 (1924).
Steenbock, H. The induction of growth promoting and calcifying properties in a ration
by exposure to light. Science 60:224-225 (1924).
Windaus, A., Linsert, O. Luttringhaus, A. and Weidlinch, G. Uber das krystallistierte
Vitamin D2. Justis. Liebigs. Ann. Chem. 492:226-231 (1932).
Brockmann, H. Die Isolierung des antirachitischen Vitamins aus Thunfischleberol. H.S.Zeit. Physiol. Chem. 241:104-115 (1936).
Crowfoot-Hodgkin, D., Webster, M.S. and Dunitz, J.D. Structure of calciferol. Chem.
Industry 1148-1149 (1957).
Solecki, R.S. Shanidar: The Humanity of Neanderthal Man, New York: Knopf. pp. 1-252
(1971).
Article was Last Updated: November 2011.
Chemistry
Chemistry of Vitamin D
The structures of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol)
and their provitamins are presented in Figure 1 on the right.
Vitamin D is a generic term and indicates a molecule of the general structure shown for rings
A, B, C, and D with differing side chain structures. The A, B, C, and D ring structure is
derived from the cyclopentanoperhydrophenanthrene ring structure for steroids. Technically
vitamin D is classified as a seco-steroid. Seco-steroids are those in which one of the rings has
been broken; in vitamin D, the 9,10 carbon-carbon bond of ring B is broken, and it is
indicated by the inclusion of "9,10-seco" in the official nomenclature.
Vitamin D (calciferol) is named according to the revised rules of the International Union of
Pure and Applied Chemists (IUPAC). Because vitamin D is derived from a steroid, the
structure retains its numbering from the parent compound cholesterol. Asymmetric centers are
designated by using the R,S notation; the configuration of the double bonds are notated E for
"entgegen" or trans, and Z for "zuzammen" or cis. Thus the official name of vitamin D3 is
9,10-seco(5Z,7E)-5,7,10(19)cholestatriene-3b-ol, and the official name of vitamin D2 is 9,10seco(5Z,7E)-5,7,10(19), 22-ergostatetraene-3b-ol.
Vitamin D3 can be produced photochemically by the action of sunlight or ultraviolet light
from the precursor sterol 7-dehydrocholesterol which is present in the epidermis or skin of
man and most higher animals. The chief structural prerequisite of a provitamin D is that it be
a sterol with a D5,7 diene double bond system in ring B (Figure 2 to the left). The conjugated
double bond system in this specific location of the molecule allows the absorption of light
quanta at certain wavelengths in the UV range; this can readily be provided in most
geographical locations by natural sunlight (or UV-B). This initiates a complex series of
transformations ( partially summarized above in Fig. 1) that ultimately results in the
appearance of vitamin D3. Thus, it is important to appreciate that vitamin D3 can be
endogenously produced and that as long as the animal (or human) has access on a regular
basis to sunlight there is no dietary requirement for this vitamin.
References
Crowfoot-Hodgkin, D., Webster, M.S. and Dunitz, J.D. Structure of Calciferol. Chem.
Industry 1148-1149 (1957).
Calverley, M.J. and Jones, G. Vitamin D. In: Antitumor Steroids, edited by Blickenstaff, R.T.
San Diego: Academic Press, pp. 193-270 (1992).
Ikekawa, N. and Ishizuka, S. Molecular structure and biological activity of vitamin D
metabolites and their analogs. In: Molecular Structure and Biological Activity of Steroids.
Boca Raton: CRC Press, pp. 293-316 (1993).
Zhu, G.-D and Okamura, W.H. Synthesis of vitamin D (calciferol). Chem. Rev. 95:1877-1952
(1995).
Ma,Y.; Khalifa,B.; Yee,Y.K.; Lu,J.; Memezawa,A.; Savkur,R.S.; Yamamoto,Y.;
Chintalacharuvu,S.R.; Yamaoka,K.; Stayrook,K.R.; Bramlett,K.S.; Zeng,Q.Q.;
Chandrasekhar,S.; Yu,X.P.; Linebarger,J.H.; Iturria,S.J.; Burris,T.P.; Kato,S.; Chin,W.W.;
Nagpal,S. Identification and characterization of noncalcemic, tissue-selective,
nonsecosteroidal vitamin D receptor modulators J. Clin.Invest.116:892-904 (2006).
Zhang,F.; Nunes,M.; Segmuller,B.; Dunphy,R.; Hesse,R.H.; Setty,S.K. Degradation
chemistry of a Vitamin D analogue (ecalcidene) investigated by HPLC-MS, HPLC-NMR and
chemical derivatization J. Pharm. Biomed. Anal. 40: 850-863 (2006).
Article Last Updated: November 2011.
Nutritional Aspects of Vitamin D
Introduction
A "vitamin" by definition is a substance regularly required by the body in small
amounts but which the body cannot make and is, therefore, required to be supplied in
the daily diet. Technically the molecular species classified as vitamin D3 is not really a
vitamin because it can be produced by exposure of the skin to sunlight (see section
on Chemistry). However, for nutritional and public health reasons, vitamin D3
continues to be classified officially as a vitamin (see section on History of Vitamin D).
Nutritional Aspects
The World Health Organization had responsibility for defining the "International Unit"
of vitamin D3. Their most recent definition, provided in 1950 states that "the
International Unit of vitamin D recommended for adoption is the vitamin D activity of
0.025 micrograms (25 nanograms) of the international standard preparation of
crystalline vitamin D3". Thus, 1.0 IU of vitamin D3 is 25 nanograms, which is
equivalent to 65.0 pmoles. With the discovery of the metabolism of vitamin D3 to other
active seco-steroids, particularly 1α,25(OH)2D3, it was recommended that 1.0 unit of
1α,25(OH)2D3 be set equivalent in molar terms to that of the parent vitamin D3. Thus,
1.0 unit of 1α,25(OH)2D3 has been operationally defined to be equivalent to 65 pmoles.
The vitamin D requirement for healthy adults has never been precisely defined. Since
vitamin D3 is produced in the skin after exposure to sunlight, the human does not
have a requirement for vitamin D when sufficient sunlight is available. However,
vitamin D does become an important nutritional factor in the absence of sunlight. It is
known that a substantial proportion of the U.S. population is exposed to quite
suboptimal levels of sunlight especially during the winter months; it is likely that
during these intervals that a regular dietary supply of vitamin D3 should be provided.
In addition to geographical and seasonal factors, ultraviolet light from the sun may
also be blocked by air pollution. The tendency to wear clothes, to live in cities where
tall buildings block adequate sunlight from reaching the ground, to live indoors, to use
synthetic sunscreens that block ultraviolet rays, and to live in geographical regions of
the world that do not receive adequate sunlight, all contribute to the inability of the
skin to biosynthesize sufficient amounts of vitamin D3. Under these conditions
vitamin D becomes a true vitamin in that it must be supplied in the diet on a regular
basis.
Since vitamin D3 can be endogenously produced by the body and since it is retained
for long periods of time by vertebrate tissue, it is difficult to determine with precision
the minimum daily requirements for this seco-steroid. The requirement for vitamin D is
also known to be dependent on the concentration of calcium and phosphorus in the
diet, the physiological stage of development, age, sex, degree of exposure to the sun,
and the amount of pigmentation in the skin.
In November of 2010, , the Institute of Medicine's (IOM) special committee of 15
experts from the US and Canada issued its report for the citizens of both countries
defining the formal Dietary Reference Intakes (average daily doses) of vitamin D and
calcium required for good health. Their recommendation for vitamin D is that from
ages 1 to 70, people need to consume no more than 600 International Units (IU) per
day. For individuals 70 or older, the recommendation is 800 IU/day to maintain strong
bone. This is only a modest adjustment of the very conservative advice rendered by
the 1997 IOM committee of 200 – 600 IU/day, depending upon age.
In the United States, adequate amounts of vitamin D can readily be obtained from the
diet and from casual exposure to sunlight. However, in some parts of the world where
food is not routinely fortified and sunlight is often limited during some periods of the
year, obtaining adequate amounts of vitamin D becomes major problem. The 13th and
14th Vitamin D Workshops reported in white papers that two thirds of the world
population has a vitamin D deficiency.
Vitamin D3 versus Vitamin D2
For decades since the determination of the chemical structures of vitamin D3 and
vitamin D2 in the 1930's it has been assumed that both vitamins had equivalent
biological activity in humans. This was based on biological determination in rats of
their comparative antirachitic activity. However in 1997, the IOM vitamin D reference
intake publication for vitamin D, serum 25-hydroxyvitamin D [25(OH)D], rather than
antirachitic activity, was defined as the functional indicator of vitamin D status.
In a 2010 paper by R. Heaney and coworkers it was reported that vitamin D3 is
approximately 87% more potent in raising and maintaining serum 25(OH)D levels than
was vitamin D2. In addition, vitamin D3 produced a 2- to 3-fold greater storage of
vitamin D than does equimolar D2. For
neither was there evidence of sequestration in fat, as had been postulated for doses in
this range.
Thus the authors felt that given the greater potency and lower cost, vitamin D3 should
be the preferred choice for correcting vitamin D deficiency in humans.
Food Sources
Animal products constitute the bulk source of vitamin D that occurs naturally in
unfortified foods. Salt water fish such as herring, salmon, sardines, and fish liver oils
are good sources of vitamin D3. Small quantities of vitamin D3 are also derived from
eggs, veal, beef, butter, and vegetable oils while plants, fruits, and nuts are extremely
poor sources of vitamin D. In the United States, artificial fortification of foods such as
milk (both fresh and evaporated), margarine and butter, cereals, and chocolate mixes
help in meeting the RDA recommendations.
References:
Heaney,R.P.; Recker,R.R.; Grote,J.; Horst,R.L.; Armas,L.A. Vitamin D3 is more potent
than vitamin D2 in humans J.Clin.End.Metab.93: 447-452 (2011).
Vieth, R.., Why the minimum desirable serum 25-hydroxyvitamin D level should be 75
nmol (30 ng/ml), Best Practice & Research- Clinical endocrinology & Metabolism,
25:681-692 (2011).
Bouillon, R.., Why modest but widespread improvement of vitamin D status is the best
strategy. Best Practice & Research- Clinical endocrinology & Metabolism, 25:693692702 (2011).
Institute of Medicine (2011) Dietary Reference Intakes for Calcium and Vitamin D.
Washington, DC: National Academies Press.
Norman, A.W. and Bouillon, R. Vitamin D nutritional policy needs a vision for the
future. Exp. Biol. Med. 235:1034-1045 (2010).
Henry, H.L., Bouillon, R., Norman, A.W., Gallagher, J.C., Lips, P., Heaney, R.P., Vieth,
R.,Pettifor, J.M., Dawson-Hughes, B., Lamberg-Allardt, C.J., and Ebeling, P.R. 14th
Vitamin D Workshop consensus on vitamin D nutritional guidelines. J. Steroid
Biochem. Mol. Biol. 121:4-6 (2010).
Norman, A.W. From Vitamin D to hormone D: Fundamentals of the vitamin D endocrine
system essential for good health. Amer. J. Clin. Nutrition. 88(2):4915-4995 (2008).
Vieth, R., Bischoff-Ferrari, H., Boucher, B., Dawson-Hughes, B., Garland, C., Heaney,
R., Holick, M., Hollis, B., Lamberg-Allardt, C., McGrath, J., Norman, A., Scragg, R.,
Whiting, S., Willett, W., and Zittermann, A. The urgent need to recommend an intake of
vitamin D that is effective. Am. J. Clin. Nutr. 2007 85: 649-650 (2007).
Norman, A.W., Henry, H.L. Vitamin D In: Present Knowledge in Nutrition, 9th Edition,
(Bownam, B.A. and Russell, R.M.), International Life Sciences Institute, Washington
D.C. Chapter 12, pp 198-210 (2006).
Subcommittee on the Tenth Edition of the RDAs, Food & Nutrition Board, Commission
on Life Sciences and National Research Council. Recommended dietary allowances,
Washington, D.C.: National Academy Press. Ed. 10th pp. 1-285 (1989).
Dietary reference intakes for calcium, magnesium, phosphorus, vitamin D, and
fluoride. Food and Nutrition Board, Institute of Medicine. Washington, DC: National
Academy Press (1997).
Article Last Updated: November 2011.
Biochemistry and Physiology of Vitamin D
Biochemistry and Physiology of the Vitamin D Endocrine System
A detailed study of the biochemical mode of action of the fat-soluble vitamin D was not
possible until the availability in the 1960s of preparations of high specific activity radioactive
vitamin D. As a consequence of efforts in several laboratories a new model emerged in the
late 1960’s to describe the biological mechanisms of action of vitamin D3. This model is
based on the concept that, in terms of its structure and mode of action, vitamin D is similar to
the classic steroid hormones, e.g. aldosterone, testosterone, estradiol, progesterone, cortisol,
and ecdysterone.
As summarized in the figure on the left, the existence of the vitamin D endocrine system is
now firmly established.
The key elements of the vitamin D endocrine system include the following:
(a) In the skin, photoconversion of 7-dehydrocholesterol to vitamin D3 or dietary intake
of vitamin D3.
(b) Metabolism of vitamin D3 by the liver to 25(OH)D3; this the major form of vitamin D
circulating in the blood compartment.
(c) Functioning of the kidney as an endocrine gland, to metabolize 25(OH)D3 to produce
the two principal dihydroxylated vitamin D metabolites, namely 1a,25(OH)2D3 and
24R,25(OH)2D3.
(d) Systemic transport of the dihydroxylated metabolites 1a,25(OH)2D3 and
24R,25(OH)2D3 to distal target organs by the plasma vitamin D binding protein (DBP).
(e) Binding of the dihydroxylated metabolites, particularly 1a,25(OH)2D3, to a receptor a
that is localized in the nucleus and plasma membrane of t the target organs followed by
the subsequent generation of appropriate biological responses (both genomic and rapid
responses).
An additional key component in the operation of the vitamin D endocrine system is the
plasma vitamin D binding protein (DBP) that carries the hydrophobic vitamin D3 and all of its
metabolites through the circulatory system to their various target organs. A target organ, by
definition will have the vitamin receptor, the VDR.
Since 1971, research efforts have largely focused upon understanding how 1a,25(OH)2D3
generates biological responses. From 1960 – 2021approximately 25,000 scientific papers
were published that used the term vitamin D either in the title or abstract. By comparison, the
biological actions of 24R,25(OH)2D3 have been relatively less studied. However, evidence
has been presented to support the view that the combined presence of both 1a,25(OH)2D3 and
24R,25(OH)2D3 are required to generate the complete spectrum of biological responses
attributable to the parent vitamin D.
Metabolism of Vitamin D
Thus, vitamin D3 is, in reality, a prohormone and is not known to have any intrinsic biological
activity itself. It is only after vitamin D3 is metabolized, first into 25(OH)D3 in the liver, and
then into 1a,25(OH)2D3 and 24R,25(OH)2D3 by the kidney, that biologically active molecules
are produced. In toto some 37 vitamin D3 metabolites have been isolated and chemically
characterized.
The key kidney enzymes, the 25(OH)D3-1-hydroxylase and the 25(OH)D3-24-hydroxylase, as
well as the liver vitamin D3-25-hydroxylase, are all known to be cytochrome P-450 mixedfunction oxidases. Both of the renal enzymes are localized in mitochondria of the proximal
tubules of the kidney. Mixed-function oxidases use molecular oxygen as the oxygen source
instead of water. Mitochondrial mixed-function oxidases are composed of three proteins that
are integral components of the mitochondrial membrane; they are renal ferredoxin reductase,
renal ferredoxin, and cytochrome P-450.
The most important point of regulation of the vitamin D endocrine system occurs through the
stringent control of the activity of the renal 1-hydroxylase. In this way the production of the
hormone 1a,25(OH)2D3 can be modulated according to the calcium and other endocrine needs
of the organism. The chief regulatory factors are 1a,25(OH)2D3 itself, parathyroid hormone
(PTH), and the serum concentrations of calcium and phosphate. The most important
determinant of the 1-hydroxylase activity is the vitamin D status of the animal. When
circulating concentrations of 1a,25(OH)2D3 are low, production of 1a,25(OH)2D3 by the
kidney is high, and when circulating concentrations of 1a,25(OH)2D3 are high, the output of
1a,25(OH)2D3 by the kidney is sharply reduced.
Actions of the vitamin D receptor:
1a,25(OH)2D3working with its VDR is known to selectively activate ≈ 3% of the some 22,000
genes of the human genome. The regulation of gene transcription by 1a,25(OH)2D3 is known
to be mediated by interaction of this ligand with its personal nuclear receptor protein, termed
the VDR. The VDR is known to occur in over 35 different cell types. 1a,25(OH)2D3 when
bound to the VDR regulates the transcription of numerous proteins. In addition, the VDR is
known to localize with the plasma membrane of the target cell where it initiates rapid
responses (e.g. opening of chloride or calcium channels or stimulating exocytosis). A number
of excellent articles have appeared describing the current understanding of how the VDR
regulates both gene transcription and rapid responses.
References
References for lay persons:
Norman, A.W., Henry, H.L. Vitamin D In: Present Knowledge in Nutrition, 9th Edition,
(Bownam, B.A. and Russell, R.M.), International Life Sciences Institute, Washington D.C.
Chapter 12, pp 198-210 (2006).
Comprehensive references to review articles covering all aspects of vitamin D with particular
emphasis on 1a,25(OH)2D3:
Vitamin D, 3rd Ed. Edited by Feldman, D., Pike, J.W, Adams, J.S. San Diego, Academic
Press, pp. 1-2081 (2011).
Henry, H.L., Regulation of vitamin D metabolism, Best Practice & Research- Clinical
endocrinology & Metabolism, 25:531-541 (2011).
Haussler, M.R., Jurutka, P.W., Mizwicki, M., & Norman, A.W., Vitamin D receptor (VDR)mediated actions of 1a,25(OH)2-vitamin D3: Genomic and non-genomic mechanisms. Best
Practice & Research- Clinical endocrinology & Metabolism, 25:543-559 (2011).
Bouillon,R.; Carmeliet,G.; Verlinden,L.; van Etten,E.; Verstuyf,A.; Luderer,H.F.; Lieben,L.;
Mathieu,C.; Demay,M., Vitamin D and human health: Lessons from vitamin D receptor null
mice, Endocr.Rev.6: 726-776 (2008).
Pike,J.W.; Meyer,M.B.; Watanuki,M.; Kim,S.; Zella,L.A.; Fretz,J.A.; Yamazaki,M.;
Shevde,N.K., Perspectives on mechanisms of gene regulation by 1,25-dihydroxyvitamin D3
and its receptor, J.Steroid Biochem.Mol.Biol., 103: 389-395 (2007).
Norman, A.W. Vitamin D Receptor (VDR): New assignments for an already busy receptor.
Endocrinology 147: 5542-5548 (2006).
Bouillon, R., Okamura, W.H. and Norman, A.W. Structure-function relationships in the
vitamin D endocrine system. Endocr. Rev. 16:200-257 (1995).
Disease and Vitamin D
The figure to the right summarizes the contributions of vitamin D to good health. Over
the past decade, four lines of investigation have collectively yielded striking new
insights into the many newly appreciated actions of vitamin D. These include the
following: (i) a broad range of molecular and cellular effects of 1a,25(OH)2D3; (ii)
experimental studies in the VDR-KO mouse model; (iii) several large observational
epidemiological studies in subjects with variable nutritional vitamin D status ; and (iv)
prospective randomized intervention studies with vitamin D.
Consequently, evidence has accumulated that beside the calcium homeostasis
system (intestine, kidney, bone and the parathyroid gland) there are five additional
physiological systems where VDR + 1α,25(OH)2D generates essential biological
responses; see the first column under the header of Physiological Systems.. These
include the immune system (both innate and adaptive), pancreas and glucose and fat
metabolism, heart-cardiovascular, muscle and brain systems as well as the control of
the cell cycle in virtually all cells and thus of the disease process of cancer
Acting through the VDR, 1a,25(OH)2D can produce a wide array of favorable biological
effects that collectively are projected to contribute to the improvement of human
health.; see the second column under the header Biological Responses. The third
column under the header VitaminD Deficiency Associated Diseases identifies for each
physiological system some of the disease states that are associated with an
inadequate vitamin D nutritional status. The supporting information for this figure
have been published in Norman, A.W. and Bouillon, R. Vitamin D nutritional policy
needs a vision for the future. Exp. Biol. Med. 235:1034-1045 (2010).
Conceptually, human clinical disorders related to vitamin D can be considered as
those arising because of (a) altered availability of vitamin D; (b) altered conversion of
vitamin D3 to 25(OH)D3; (c) altered conversion of 25(OH)D3 to 1a,25(OH)2D3 and/or
24R,25(OH)2D3; (d) variations in end organ responsiveness to 1a,25(OH)2D3 or possibly
24R,25(OH)2D3; and (e) other conditions of uncertain relation to vitamin D. Thus, the
clinician/nutritionist/biochemist is faced with a problem, in a diagnostic sense, of
identifying parameters of hypersensitivity, antagonism, or resistance (including
genetic aberrations) to vitamin D or one of its metabolites as well as identifying
perturbations of metabolism that result in problems in production and/or delivery of
the hormonally active form, 1a,25(OH)2D3. A detailed consideration of this area is
beyond the scope of this presentation. There are many scientific publications; a list of
recent summary articles are available at the end of this presentation.
Drug Forms of 1a,25(OH)2D3
As a consequence of the significant scientific advances in the understanding of how
vitamin D generates biological responses [principally via 1a,25(OH)2D3], a number of
new drug forms of 1a,25(OH)2D3 have been generated by pharmaceutical companies.
The table below summarizes these new drugs and the relevant pharmaceutical
company, and identifies the clinical circumstance for which their use has been
authorized.
Drug Forms of Vitamin D Analogs
Compound
Name
Generic Name
Commerci
al Name
Pharmaceutical
Company
Effective
Daily Dose Approv
(microgram ed Use
s)*
1α,25(OH)2D3
CALCITRIOL
ROCALTR ROFFMAN-LA
OL
ROCHE
0.5-1.0
RO,
HP, Ob
1α,25(OH)2D3
CALCITRIOL
CALCIJEX ABBOTT
0.5 (i.v.)
HC
1α,25(OH)2-19PARICALCITOL
nor-D2
ZEMPLAR ABBOTT
2.8-7 (eod) SHP
1α,24(OH)2D3
BONALFA
TACALCITOL
TEIJIN LTD.JAPAN
1α,24S(OH)222-ene-24CALCIPOTRIENE
cyclopropyl-D3
DOVONEX LEO-DENMARK
1α,24S(OH)222-ene-24CALCIPOTRIENE
cyclopropyl-D3
DOVONEX
1α-OH-D3
ONE-ALFA LEO-DENMARK
ALFACALCIDOL
WESTWOODSQUIBB
40-80
(topical)
PP
40-80
(topical)
PP
40-80
(topical)
PP
1-2
RO,
Compound
Name
Generic Name
Commerci
al Name
Pharmaceutical
Company
Effective
Daily Dose Approv
(microgram ed Use
s)*
HP, O,
VDRR
0.25-1.0
RO, O,
HC, HP
0.25-1.0
RO, O
ONEALFA CHUGAI-JAPAN
0.25-1.0
RO, 0
DOXERCALCIFEROL
HECTORO
GENZYME
L
10
4x/WEEK
(i.v.)
SHP
CALCIFEDIOL
CALDERO
ORGANON-USA
L
50-500
RO
CALCIFEDIOL
ROUSSELDEDROGY
UCLAFL
FRANCE
50-500
RO
10,19DIHYDROTACHYSTE HYTAKER
dihydrotachyste
WINTHROP
ROL3
OL
rol3
200-1000
RO
1α,25(OH)2-22MAXACALCITOL
oxa-D3
OXAROL
5-10
3x/WEEK
(i.v.)
SHP
1α,25(OH)226,27-F6-D3
FALECALCITRIOL
SUMMITOMO
FULSTAN PHARMACEUTIC
0.15-0.34
TABLETS ALSJAPAN
HC,
SHP,
RO
FALECALCITRIOL
TAISHO
HORNEL PHARMACEUTIC
0.15-0.35
TABLETS ALSJAPAN
HC,
SHP,
RO
1α-OH-D3
ALFACALCIDOL
ALPHA-D3 TEVA-ISRAEL
1α-OH-D3
ALFACALCIDOL
ONEALFA
1α-OH-D3
ALFACALCIDOL
1α-OH-D2
25(OH)D3
25(OH)D3
1a,25(OH)226,27-F6-D3
TEIJIN LTD.JAPAN
CHUGAI-JAPAN
The key to the approved uses of the vitamin D analogs is as follows: RO = renal
osteodystrophy, O = postmenopausal osteoporosis; PP = plaque psoriasis; HC =
hypocalcemia (frequently present in patients with renal osteodystrophy who are
subjected to hemodialysis); HP = hypoparathyroidism and associated hypocalcemia
which may frequently be encountered in patients with hypoparathyroidism,
pseudohypoparathyroidism or in circumstances of post-surgical hypoparathyroidism;
SHP = secondary hyperparathyroidism associated with renal osteodystrophy; VDRR =
vitamin D-resistant rickets.
a
Oral dose unless otherwise indicated; eod = every other day
b
The use of Rocaltrol for postmenopausalosteoporosis is approved in Argentina,
Australia, Austria, Czech Republic, Columbia, India, Ireland, Italy, Japan, Malaysia,
Mexico, New Zealand, Peru, Philippines, South Korea, South Africa, Switzerland,
Turkey, and the United Kingdom.
NOTE: This Table 1 was published in Present Knowledge in Nutrition, 9th edition by A.
W. Norman & H..L. Henry (Bohman, B. A and Russell, R. M.) International Life Sciences
Institute, Washington D.C.; Chapter 12, pp. 198- 210 (2006).
References
Vitamin D, 3rd Ed. Edited by Feldman, D., Pike, J.W, Adams, J.S. San Diego, Academic
Press, pp. 1-2081 (2011).
Holick, M.F., Binkley, N.C., Bischoff-Ferrari, H.A., Gordon, C.M., Hanley, D. A., Heaney,
R. P., Murad, M. H., and Weaver, C. M., Evaluation, treatment and prevention of vitamin
D deficiency: An Endocrine Society clinical practice guideline. J. Clin. Endoctinol.
Metab. 96: 1911-1930 (2011).
Lappe, J.M., The role of vitamin D in human health: A paradigm shift, J. EvidenceBased Complementary & Alternative Medicine, 16:58-72 (2011).
Haussler, M.R., Jurutka, P.W., Mizwicki, M., & Norman, A.W., Vitamin D receptor (VDR)mediated actions of 1a,25(OH)2-vitamin D3: Genomic and non-genomic mechanisms.
Best Practice & Research- Clinical endocrinology & Metabolism, 25:543-559 (2011).
Henry, H.L., Regulation of vitamin D metabolism, Best Practice & Research- Clinical
endocrinology & Metabolism, 25:531-541 (2011).Best Practice & Research- Clinical
endocrinology & Metabolism, 25:543-559 (2011).
Bouillon,R.; Carmeliet,G.; Verlinden,L.; van Etten,E.; Verstuyf,A.; Luderer,H.F.;
Lieben,L.; Mathieu,C.; Demay,M., Vitamin D and human health: Lessons from vitamin
D receptor null mice, Endocr.Rev.6: 726-776 (2008).
Melamed, ML, Michos, ED, Post, W, Astor, B. 25-hydroxyvitamin D levels and the risk
of mortality in the general population. 6 168: 1629-1637, 2008.
Pike,J.W.; Meyer,M.B.; Watanuki,M.; Kim,S.; Zella,L.A.; Fretz,J.A.; Yamazaki,M.;
Shevde,N.K., Perspectives on mechanisms of gene regulation by 1,25dihydroxyvitamin D3 and its receptor, J.Steroid Biochem.Mol.Biol., 103: 389-395
(2007).
Bouillon, R, Verstuyf, A, Mathieu, C, Van, CS, Masuyama, R, Dehaes, P, Carmeliet, G.
Vitamin D resistance.6 20: 627-645, 2006,
H.P. and Norman, A.W. The role of the vitamin D endocrine system in health and
disease. New Engl. J. Med. 320:980-991 (1989).
Vitamin D and Milk
Prepared by Professor Anthony W. Norman;
Department of Biochemistry & Biomedical Sciences
University of California, Riverside CA 92521
(December 12, 2000 & updated in 2011)
Purpose of this statement:
The objective of this presentation is to provide a brief descriptions of vitamin D's chemistry,
nutritional importance, sources, production and presence in milk. This will first require a
review of the biological and nutritional background on vitamin D, which is a precursor of a
steroid hormone [1a,25(OH)2D3] in higher animals, including humans.
What is a vitamin?
A vitamin is a substance (a specific organic molecule) whose presence is crucial to the normal
every day life and functions of animals. However vitamins can not be directly produced by
the animal's body. Accordingly, the daily requirements for each vitamin must be met through
regular dietary intake of appropriate quantities of the vitamin(s). There are two general
chemical categories of vitamins based on their solubility: water soluble vitamins (the B
vitamins and others) and fat soluble vitamins (A, D, E and K).
What is a hormone?
A hormone is a chemical messenger that is produced and secreted by specific glands and cells
within the body of animals. After secretion of the hormone, it is transported through the
bloodstream to designated target organs where the hormone by binding to its specific personal
receptor delivers its "message" to that set of cells. These cells then promptly produce
biological responses specific for that hormone.
What is vitamin D and why is it important:
Chemistry: There are two chemical forms of vitamin D, namely vitamin D2 (sometimes
referred to as ergocalciferol) and vitamin D3 (sometimes referred to a cholecalciferol). The
natural form of vitamin D for animals and man is vitamin D3; it can be produced in their
bodies from cholesterol and 7-dehydrocholesterol. An alternative vitamin D2 is commercially
prepared from ergosterol that is present in yeast.
The molecular structure of vitamin D is closely allied to that of the classical steroid hormones,
e.g. cortisol, estradiol, progesterone, aldosterone, and testosterone (3). All steroid hormones
and vitamin D3 are chemically related to the well known sterol cholesterol. Cholesterol in
animals and man is a precursor substance for all steroid hormones and as well vitamin D3.
Technically the molecule called vitamin D3 is not really a vitamin because it can be produced
by exposure of the skin (higher animals and humans) to ultraviolet light or sunlight. The skin
of many animals and man has a high concentration of the sterol cholesterol which is converted
by enzymes in the skin to the sterol 7-dehydrocholesterol. Exposure of skin (including human
skin) to sunlight for regular intervals results in the photochemical conversion of 7dehydrocholesterol into vitamin D3. This sunlight- generated vitamin D3 is a precursor of the
steroid hormone 1a,25(OH)2D3. Under these circumstances vitamin D3 is not a vitamin
because it has been produced by the body (with the assistance of sunlight). However, if the
animal or man lives in the absence of sunlight (e.g., Alaska in the winter) or exclusively
indoors, then there is indeed an absolute regular requirement for the fat soluble vitamin D,
that must be met through proper dietary intake.
Therefore for nutritional and public health reasons, vitamin D3 continues to be classified even
today in 2012 officially as a vitamin. Thus many vitamin capsules and food sources including
cows milk are supplemented with vitamin D3 to improve their nutritional value. In the 1940's
this milk supplementation process reduced the incidence rate of juvenile rickets by 85% in the
United States.
Importance: Vitamin D3 is essential for life in higher animals. Classically vitamin D3 has
been shown to be one of the most important biological regulators of calcium metabolism
through stimulating the absorption of calcium from food across the intestine and participating
in the incorporation of the absorbed calcium into the skeleton (2). These important biological
effects are only achieved as a consequence of the metabolism of vitamin D into a family of
daughter metabolites, including 1a,25(OH)2-vitamin D3 [1a,25(OH)2D3]. 1a,25(OH)2D3, is
considered to be a steroid hormone because the general mechanism by which it produces the
biological responses attributed to vitamin D is similar to those of steroid hormones (3;4).
It has become increasingly apparent since the 1980s that 1a,25(OH)2D3 also plays an
important multidisciplinary role in tissues not primarily related to mineral metabolism, e.g.
activation of the immune system, both innate and adaptive, in the pancreas where it facilitates
insulin secretion, in muscle where it improves muscle strength, and in the heart and
cardiovascular systems, where it is concerned with heart muscle function and blood pressure
regulation.,
Vitamin D Deficiency: The classic deficiency state resulting from a dietary absence of
vitamin D3 or lack of ultraviolet (sunlight) exposure is the bone disease called rickets in
children or osteomalacia in adults. The clinical features of rickets and osteomalacia depend
upon the age of onset. The classical skeletal disorder of rickets includes deformity of the
bones, especially in the knees, wrists, and ankles, as well as associated changes in the rib joint
functions, which have been termed by some as the rachitic rosary (1). A regular access to
vitamin D3 throughout life is important to facilitate the normal absorption into the body of
dietary calcium which, in turn, is essential for normal bone health and may diminish or
prevent the onset in the elderly of the bone disease osteoporosis.
Requirements for vitamin D:
Since vitamin D3 is produced in the skin after exposure of 7-dehydrocholesterol to sunlight,
the human does not have a requirement for vitamin D when sufficient sunlight is available.
Man's tendency to wear clothes, to live in cities where tall buildings block adequate sunlight
from reaching the ground, to live indoors, to use synthetic sunscreens that block ultraviolet
rays, and to live in geographical regions of the world that do not receive adequate sunlight, all
contribute to the inability of the skin to biosynthesize sufficient amounts of vitamin D3 (5).
Thus, vitamin D3 does become an important nutritional factor in the absence of sunlight. It is
known that a substantial proportion of the U.S. population is exposed to suboptimal levels of
sunlight. This is particularly true during winter months (6;7). Under these conditions, vitamin
D becomes a true vitamin which dictates that it must be supplied in the diet on a regular basis.
Since vitamin D3 can be produced by the body and since it is retained for long periods of time
by animal tissues, it has been difficult to determine with precision the minimum daily
requirements for this fat soluble vitamin. The requirement for vitamin D3 is also known to be
dependent on the age, sex, degree of exposure to the sun, season, and the amount of
pigmentation in the skin (8).
The current "adequate intake" allowance of vitamin D recommended in 2010 by the Food and
Nutrition Board of the US Institute of Medicine is 600 IU/day (15 µgrams/day) for children
and adult males and females up to age 70 (9). For adults greater than 70 years, the
recommended intake is 800 IU (20 µgrams/day).The adequate allowance for pregnancy and
lactation is set at 600 IU/day (15 µg/day). These recommendations are all summarized in a
2010 publication from the Food and Nutrition Board of the Institute of Medicine (9).
In the United States adequate amounts of vitamin D3 can readily be obtained from the diet
and/or from casual exposure to sunlight. The ultraviolet exposure can be as little as 3 X per
week exposure of the face and hands to ambient sunlight for 20 minutes (10). However, in
some parts of the world where food is not routinely fortified and sunlight is often limited
during some periods of the year, obtaining adequate amounts of vitamin D becomes more of a
problem. As a result, the incidence of rickets in these countries is higher than in the United
States.
What are the sources of vitamin D for humans?
Animal products constitute the primary source of vitamin D that occurs naturally in
unfortified foods. Salt water fish such as herring, salmon, sardines, and fish liver oils are good
sources of vitamin D3. Small quantities of vitamin D3 are also found in eggs, veal, beef,
butter, and vegetable oils while plants, fruits, and nuts are extremely poor sources of vitamin
D. In the United States, fortification of foods such as milk (both fresh and evaporated),
margarine and butter, cereals, and chocolate mixes help in meeting the adequate intake (RDA)
recommendations (11). Because only fluid milk is fortified with vitamin D, other dairy
products (cheese, yogurt, etc.) only provide the vitamin that was produced by the animal
itself.
How is vitamin D produced commercially for food supplementation>
When the critical importance to human health of a regular dietary access to vitamin D3 was
understood (in the 1930's), milk suppliers realized it would be advantageous to their
customers' health to market milk which had been supplemented with vitamin D3. Thus there
developed in the 1940's, and continues to the present, a large business of industrial production
of vitamin D3 used for the supplementation of foods for human consumption: milk (both
homogenized and evaporated), some margarine and breads. Since the 1960's vitamin D3 has
been used also for the supplementation of farm animal and poultry food.
In 1973 in the United States some 290 trillion (290 x 10-12) International Units of vitamin D3
was manufactured and sold for over 3 million dollars. This vitamin D3 is the equivalent of
approximately 8 tons.
The commercial production of vitamin D3 is completely dependent on the availability of
either 7-dehydrocholesterol or cholesterol. 7-Dehydrocholesterol can be obtained via organic
solvent extraction of animal skins (cow, pig or sheep) followed by an extensive purification.
Cholesterol typically is extracted from the lanolin of sheep wool and after thorough
purification and crystallization can be converted via a laborious chemical synthesis into 7dehydrocholesterol. It should be appreciated that once chemically pure, crystalline 7dehydrocholesterol has been obtained, it is impossible to use any chemical or biological tests
or procedures to determine the original source (sheep lanolin, pig skin, cow skin, etc.) of the
cholesterol or 7-dehydrocholesterol.
Next the crystalline 7-dehydrocholesterol is dissolved in an organic solvent and irradiated
with ultraviolet light to carry out the transformation (similar to that which occurs in human
and animal skin) to produce vitamin D3. This vitamin D3 is then purified and crystallized
further before it is formulated for use in dairy milk and animal feed supplementation. The
exact details of the chemical conversion of cholesterol to 7-dehydrocholesterol and the
method of large-scale ultraviolet light conversion into vitamin D3 and subsequent purification
are closely held topics for which there have been many patents issued (3).
Historically, the major producers of vitamin D3 used for milk and other food supplementation
were the companies F. Hoffman La Roche, Ltd (Switzerland) and BASF (Germany). Today
much of the commercially produced vitamin D2 is manufactured in China.
What is the source of vitamin D in milk?
Milk from all lactating animals, including humans, contains vitamin D3 that has been
produced photochemically from 7-dehydrocholesterol present in the skin. In cow's milk it has
been determined that the concentration of vitamin D3 in milk provided by the cow is roughly
35-70 International Units per quart as determined via biological assay (12) and approximately
50-80 International Units as determined by modern chemical mass spectrometric procedures
(13). However these are rather low levels of vitamin D3 from the perspective of providing the
600 IU per day as recommended by the Food and Nutrition Board of the Institute of Medicine
in 2010.. Accordingly, as discussed above, the business practice of supplementing cows milk
with chemically synthesized vitamin D3 was initiated. At the present time almost all milk sold
commercially in the United States has 400 IU of chemically synthesized vitamin D3 added
per quart. Any vendor of milk for human consumption containing added vitamin D3 is
required by the US Food and Drug Administration (FDA) to include a notice on the milk
carton label. Usually this label states "400 IU of added vitamin D3". However it is not
required by law to indicate either the manufacturer of the added vitamin D3 or the sources of
the cholesterol and 7-dehydrocholesterol used for its production.
It is a fact that most milk sold in the US will contain vitamin D3 with two origins. (a) That
vitamin D3 made by the cow using sunlight to irradiate 7-dehydrocholesterol present in her
skin. (b) That vitamin D3 made by a chemical process and then added to the cow milk as a
nutritional supplement. It is simply not possible to distinguish the origins of the two vitamin
D3 preparations by any biological or chemical procedure, because they are the same
molecular structure. Further, there is no legal requirement for the manufacturer of the vitamin
D3 formulated for human food supplementation to specify the animal sources of the precursor
molecules that were employed in the synthesis of the D vitamin.
If a "food product" is construed to include a chemically pure substance that is the same in all
animal species, then those individuals with strict religious reasons for avoiding food products
from a particular species have, in the instance of milk and vitamin D3, a dilemma.
Selected references:
Also the WEB sites for the Vitamin D Workshop and provides other general information
related to vitamin D.
Reference List
1. Norman,A.W. and Litwack,G.L. Hormones, Academic Press, San Diego,
CA.(1997).
2. Norman,A.W. Vitamin D: The calcium homeostatic steroid hormone., Academic
Press, New York.(1979).
3. # Bouillon,R., Okamura,W.H., and Norman,A.W. Structure-function relationships
in the vitamin D endocrine system. Endocr.Rev. 16 (1995) 200-257.
4. Norman,A.W.: Vitamin D. In Present knowledge in nutrution (PKN7). Ziegler,E.E.
and Filer,L.J., Eds., International Life Sciences Institute, Washington (1996) pp.
120-129 .
5. Holick,M.F. Environmental factors that influence the cutaneous production of
vitamin D. Am.J.Clin.Nutr. 61 Suppl. (1995) 638S-645S.
6. Webb,A.R. and Holick,M.F. The role of sunlight in the cutaneous production of
vitamin D3. Ann.Rev.Nutr. 8 (1988) 375-399.
7. Webb,A.R., Pilbeam,C., Hanafin,N., and Holick,M.F. An evaluation of the relative
contributions of exposure to sunlight and of diet to the circulating
concentrations of 25-hydroxyvitamin D in an elderly nursing home population
in Boston. Am.J.Clin.Nutr. 51(6) (1990) 1075-1081.
8. Harris,S.S. and Dawson-Hughes,B. Seasonal changes in plasma 25hydroxyvitamin D concentrations of young American black and white women.
Am.J.Clin.Nutr. 67 (1998) 1232-1236.
9. Food and Nutrition Board. Dietary reference intakes: A risk assessment model
for establishing upper intake levels for nutrients. 1998) , 1-71. Washington, D.C.,
National Academy Press, Institute of Medicine.
10. Adams,J.S., Clemens,T.L., Parrish,J.A., and Holick,M.F. Vitamin-D synthesis
and metabolism after ultraviolet irradiation of normal and vitamin-D-deficient
subjects. New Engl.J.Med. 306 (1982) 722-725.
11. Collins,E.D. and Norman,A.W.: Vitamin D In Handbook of vitamins. Machlin,L.J.,
Ed., Marcel Dekker, New York (1990) pp. 59-98 .
12. Hollis,B.W., Roos,B.A., and Lambert,P.W.: Vitamin D compounds in human and
bovine milk In Advances in nutritional research. Draper,H.H., Ed., Plenum
Press, New York (1994) pp. 59-75 .
13. Adachi,A. and Kobayashi,T. Identification of vitamin D3 and 7dehydrocholesterol in cow's milk by gas chromatography-mass spectrometry
and their quantitation by high-performance liquid chromatography.
J.Nutr.Sci.Vitaminol. 25 (1979) 67-78.
True or false? – The research of. Prof Bruce W. Hollis, PhD, Medical University of
South Carolina and Prof. Heaney, Robert M.D., Creighton University, invalidates all
studies about Vitamin D (RCT or not) since and including the Women’s Health
Study of 1992 with the consequence, that all the findings in these invalid
studies are merely statistical artefacts
1. True or false? – The biochemical research of Prof. Hollis destroys the
relevance of all studies with a weekly or longer dosing interval aiming at
non bone-health effects, i.e.preventing or healing chronic diseases like
cancer, arthritis, Diabetes, cardiovascular illnesses, MS or infections etc.
etc.. Prof. Hollis has proven, that only a daily dosis is a valid studyparameter in any given Vitamin – D – nutrient study. The consequence
thereof is, that all studies, negating this, produce nothing but statistical
artefacts.
2. True or false? –The biometrical finding of Prof. Heaney destroys the
relevance of all studies not in compliance with the mandatory
necessities for any given scientific-nutrient study of non bone-health
effects, i.e.preventing or healing chronic diseases like cancer, arthritis,
Diabetes, cardiovascular illnesses, MS or infections etc. etc.. The
consequence thereof is, that all studies, negating this, produce nothing
but statistical artefacts.
3. True or false? – The mandatory requirements (Heaney) for any given
nutrient study have a legal consequence. – Any RCT is from the outset
unethical.
4. True or false? – Considering the mandatory requirement für any nutrient
study, that the co-nutrients, all of them, have to be in an optimal range,
before the study starts, has financial consequences. In nearly all cases,
the money necessary for a valid nutrient study is a prohibiting factor for
valid research in the nutrient-field.
Reference: Design Components of Interventions/Studies of Vitamin D - 15.01.2015 Prof.Hollis / Prof. Heaney
https://www.youtube.com/watch?v=JGLTD9D2Yxw
http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi19.mp4
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
volker@vonabisw.de
www.vonabisw.de
Vitamin D - Research: Der aktuelle Forschungsstand 2014 zu Vitamin D spiegelt sich hier:
Dr.med. Raimund von Helden: Vitamin-D-Mangel begreifen in 4 Schritten https://www.youtube.com/watch?v=l6paj8kow54
Update zu Vitamin D3:
http://d.mp3vhs.de/vonabisw/Vitamind3/GröberHolick2013.pdf
Update zu Vitamin K2:
http://d.mp3vhs.de/vonabisw/Vitamind3/K40.pdf
University Lecture: The D-Lightful Vitamin D for Health by Prof. Michael F. Holick - 2013 https://www.youtube.com/watch?v=EP81YMvs4yI
Whats a Vitamin D Deficiency? - Robert Heaney, MD
https://www.youtube.com/watch?v=dnOEiC0yu_k
The latest on Vitamin D – September 2014 by Prof. Dr. Robert Heaney https://www.youtube.com/watch?v=B9SNfrE7P1s
Vitamin D and Sunlight for Cancer Prevention by C.F.Garland https://www.youtube.com/watch?v=-SoEBFbnMgc
Carole Baggerly: My Data - My Answers: Vitamin D – The history of grassroots health
https://www.youtube.com/watch?v=DZ5rvMKcvwM
Dr. Reinhold Vieth - Vitamin D & Policy Creation https://www.youtube.com/watch?v=P92PF_4BqNw
Vitamin D Measurement the Key to Change
https://www.youtube.com/watch?v=4wDrKxcvsKM
William B. Grant, PhD: Cost / Benefit of Optimal Health with Sunshine Vitamin D
https://www.youtube.com/watch?v=91eDzM0qiJM
Design Components of Interventions/Studies of Vitamin D
https://www.youtube.com/watch?v=JGLTD9D2Yxw
Vitamin D and Public Health Practice
http://www.uctv.tv/shows/Vitamin-D-and-Public-Health-Practice-29152
Vitamin D Usage in Alaska
https://www.youtube.com/watch?v=iD0MJvf5Lyg
Bruce W. Hollis, PhD, Medical University of South Carolina (2014) https://www.youtube.com/watch?v=QrU1yrmNIqc
Dr. Mercola Interviews Dr. Heaney on Maintaining Vitamin D Levels, Security and Toxicity
https://www.youtube.com/watch?v=FmCw8qekues
Dr. med. Anna Dorothea Höck (Köln): Fragen und Antworten http://www.vit-d.info/wp-content/uploads/2010/01/17-Fragen-und-Antworten.pdf
Prof. Dr. med. Jörg Spitz: Sonnen- und Vitamin D-Mangel in der Überflussgesellschaft
https://www.youtube.com/watch?v=W-QKbikogtI
Prof. Dr. med. Billigmann: Vitamin D im Sport
https://www.youtube.com/watch?v=XwdAIqk-z4s
Ausführlich zu Vitamin D auch: - http://www.vonabisw.de/6.html - http://www.vonabisw.de/21.html http://www.vonabisw.de/47.html
Empfohlene Literatur:
Dr. Eberhard J. Wormer: Vitamin D - 2014
-
http://www.amazon.de/Vitamin-D-Eberhard-J-Wormer/dp/3864451590/ref=sr_1_2?s=books&ie=UTF8&qid=1424882305&sr=1-2
Dr. med. Reimund von Helden: Gesund in sieben Tagen - Erfolge mit der Vitamin-DTherapie – 2014 - http://www.amazon.de/Gesund-sieben-Tagen-Erfolge-Vitamin-DTherapie/dp/3939865125/ref=sr_1_1?s=books&ie=UTF8&qid=1424882404&sr=1-1&keywords=von+helden
Uwe Gröber / Prof.Dr. med. Michael F. Holick: Vitamin D - Die Heilkraft des
Sonnenvitamins, 2012
Dr. Kate Rhéaume-Bleue: Vitamin K2 and the Calcium Paradox Known Vitamin Could Save Your Life, 2013
How a Little-
Dr. Nicolai Worm : Heilkraft D - Wie das Sonnenvitamin vor Herzinfarkt, Krebs und
anderen Krankheiten schützt - 2009
Professor Dr. Jörg Spitz, William B. Grant Ph.D. : Vitamin D - Das Sonnenhormon Warum die Sonne so wichtig für uns ist - Wie Sie Ihren Vitamin-D-Vorrat auftanken 2014
Josef Pies: Vitamin K2 -
Vielseitiger Schutz vor chronischen Krankheiten – 2012
Alan L. Rubin: Vitamin D For Dummies – 2011
Ian Wishart: Vitamin D - Is This the Miracle Vitamin?
-
2012
Meine Audiorezension zu: Eberhard J. Wormer: Vitamin D – Kopp – Verlag, Rottenburg, 2014, 256 S., €
14,95 - Heilen mit der Kraft des Sonnenhormons – eine medizinische Revolution http://d.mp3vhs.de/vonabisw/rezensionen/Wormer.mp3 - gibt es auf diesen Internetseiten http://www.vonabisw.de/18.html - http://www.vonabisw.de/6.html - http://www.vonabisw.de/21.html
- http://www.vonabisw.de/46.html - http://www.vonabisw.de/47.html
Wissenschaftliche Studien zu Vitamin D 3: - http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi1.pdf http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi2.pdf - http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi3.pdf http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi4.pdf - http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi5.pdf http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi6.pdf - http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi7.pdf http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi8.pdf - http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi9.pdf http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi10.pdf
Seriöse Informationen zu Vitamin (Hormon) D3: - http://www.vitamind.net/ - - Dr. med.Helmut B. Retzeck http://www.homeopathy.at/vitamin-d/ - - http://vitamin-d-wissen.com/ - - http://www.solartirol.at/gesundheit.html - http://www.vitamindwiki.com/For+Medical+Professionals - http://www.vitamindwiki.com/Overview+Vitamin+K+and+Vitamin+D - - Dr. von Helden - http://www.vitamindelta.de/ - Zentrum der Gesundheit - http://www.zentrum-der-gesundheit.de/vitamin-d-ia.html - - Zeiten*Schrift http://www.zeitenschrift.com/artikel/vitamin-d-das- - sonnenvitamin#.VEdYnslYiUk - - http://www.wlsproducts.de/vitamin-d350000-ie-100-kapseln-hochdosiert - - Vitamin D Service - https://www.vitamindservice.de/ - - Natural News http://www.naturalnews.com/vitamin_d.html - - vit d info - http://www.vit-d.info/ - - vitamin d council http://www.vitamindcouncil.org/ - - http://www.vitamin-d-info.org/ - - http://www.vitamin-d3-experte.com/ - https://www.lifeextensioneurope.de/vitamin-d3-5-000-iu-60softgels?gclid=Cj0KEQjwq52iBRDEvrC12Jnz6coBEiQA2otXAhNcmoXohvBCccYHmEdj0bxjhCFhK06DgRNlivfygYaAmC38P8HAQ - - https://www.vebu.de/themen/gesundheit/naehrstoffe/vitamin-d - - http://heilkraftd.de/links-zu-vitamin-d-websites.html - - https://www.youtube.com/watch?v=9FMlQeH8RFA&feature=player_embedded - http://www.ucsd.tv/series/index.aspx?show=show&seriesnumber=520 - - http://www.grassrootshealth.net/ - http://www.vitamindcouncil.org/ - - http://www.sunlightresearchforum.nl/ - http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/index.html - - http://www.healthresearchforum.org.uk/index.html - http://vitamindhealth.org/ - - http://www.vitamindsociety.org/ - - http://heilkraft-d.de/heilkraft-d-das-buch.html
Seriöses zu K2: http://www.zentrum-der-gesundheit.de/vitamin-k-ia.html - http://www.vitamin-k2.info/ http://www.orthoknowledge.eu/update_vitamin_k2/ - http://www.lef.org/en/Magazine/2008/3/Protecting-Bone-AndArterial-Health-With-Vitamin-K2/Page-01 - http://lpi.oregonstate.edu/infocenter/vitamins/vitaminK/ http://www.nlm.nih.gov/medlineplus/druginfo/natural/983.html - http://products.mercola.com/vitamin-k/ http://www.whfoods.com/genpage.php?tname=nutrient&dbid=112 - http://chriskresser.com/vitamin-k2-the-missingnutrient - http://www.eesom.com/go/G7D6FNSK3O9DQ8N71FA0ARERG7DIKA3B https://www.bulletproofexec.com/106-the-powers-of-vitamin-k2-with-dr-kate-rheaume-bleue-podcast/ -
http://doctorkatend.com/about/ - https://www.youtube.com/watch?v=fYMExQNosTQ https://www.youtube.com/watch?v=Vbd8FqnVT4c - https://www.youtube.com/watch?v=4IFhW2C1IUk https://www.youtube.com/watch?v=dNVK1QHegb4 - https://www.youtube.com/watch?v=lC3Ecx56tqE https://www.youtube.com/watch?v=QGEg6e80WYM - Dr. Kate Rhéaume-Bleue: Vitamin K2 and the Calcium
Paradox: How a Little-Known Vitamin Could Save Your Life - http://www.amazon.de/Vitamin-Calcium-Paradox-LittleKnown-Rheaume-Bleue/dp/B00M0DFI7U/ref=sr_1_2?s=books&ie=UTF8&qid=1417689377&sr=12&keywords=Kate+Rh%C3%A9aume-Bleue
Von: CustomerService@lifeextension.com [mailto:CustomerService@lifeextension.com]
Gesendet: Mittwoch, 4. März 2015 16:47
An: volker@vonabisw.de
Betreff: Case:[3345984] - Variation of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2
levels i... - PubMed - NCBI
Dear Volker Schendel ,
Thank you for your recent correspondence.
Thank you for taking the time to send us this vitamin D half-life research study.
It is important to keep in mind that the half-life of Vitamin D in the body is reported
differently in different sources because of an inconsistency in how the “half-life” is
defined. Many sources cite half-life data as the time for vitamin D to leave the blood
stream, while others may reference it as the time for vitamin D to be fully eliminated
from the body.
Upon entry into circulation from dermal synthesis, vitamin D3 binds a transport
protein that slows its delivery to the liver. By contrast, oral vitamin D3 is transported
to the liver via lipoproteins and phospholipid particles, causing a more rapid clearance
by the liver. This explains the difference in half-life between exogenous and
biosynthesized vitamin D.
Further information about this difference can be referenced in the following study:
http://ajcn.nutrition.org/content/69/5/842.full
Additionally, as vitamin D circulates and reaches target tissues, it is peripherally
distributed into adipose tissue as well as the liver for storage where it has a very slow
turnover rate. Although plasma half-life (the time for half of a measured quantity of
vitamin D to disappear from blood) is relatively short, the whole body half-life of
vitamin D is suggested to be much longer; at up to 2 months. Keep in mind that
individual differences in metabolism and body weight can affect this elimination time.
Thus, studies suggesting half-life to be 4-5 weeks may still be accurate for their
specific study subjects.
For your reference, the following study describes the pharmacokinetics of vitamin D
clearance in more detail:
http://ajcn.nutrition.org/content/88/2/582S.long
If there is anything else that we can help you with, please e-mail us or call the advisor
helpline at (800) 226-2370; international customers dial 001-954-202-7660. We will be
glad to assist you.
Hallo Volker
danke für die Info
vieles machen wir ähnlich
Vit.D mit Magnesiumcitrat und SuperK (tlw. auch 100mcg K2 Mk7)
Vitamine über frische Früchte (tlw. Smoothie mit frische Früchte, Nüsse, Leinsamen
usw.)
nur mehr selbst gebackenes Vollkornbrot (z.B. mit Dinkel , Einkorn, Roggen)
statt Zucker mehr Bio Agavensirup, Stevia, Bio Ahornsirup
fast nur mehr Natursteinsalz
hochwertige Butter (keine Margerine)
kalt gepreßtes Bio Kokosfett (für Kochen, Braten, Haut, Brotaufstrich)
hochwertiges Olivenöl (Salat)
(Kokosfett und Hanfsamen funktionieren auch optimal für Abnehmen und viel Energie
ohne Fasten)
ich verwende auch etwas Hanfsamen (super für Muskelaufbau und Fettverbrennung)
etwas Astaxanthin (Antioxidantie und Ausdauer, super Sonnenschutz von innen, sehr
gut für die Augen)
und Zeolith (Entgiftung und Mineralien für die Knochen und Gelenke)
Kaffee trinken wir relativ viel (ein Laster braucht man) wobei das Dr.Feil Team Kaffe
als gutes Lebensmittel ansieht
mfG Manfred
meine Gesundheitsseite
Von: Volker H. Schendel [mailto:volker@vonabisw.de]
Gesendet: Mittwoch, 04. März 2015 22:13
An: 'Manfred G.'
Cc: customerservice@grassrootshealth.org; Dink van Ginkel; eberhard.wormer@web.de;
Eva.Hoberg-Scholz@merckgroup.com; l.schurgers@bioch.unimaas.nl; Raimund von
Helden; schmiedel@habichtswaldklinik.de; uwegroeber@gmx.net; walach@europa-uni.de
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren Fragen an Manfred G.
Hallo Manfred,
mein Zielwert mit 20.000 I.E. / Tag ist 100 - 120 ng /ml, meine Frau mit 10.000 I.E./ Tag
strebt 80 ng / ml an.
Ich halte es da mit Dr. Eisenstein
Why You Have Not Heard The Truth About
Vitamin D
https://www.youtube.com/watch?v=F9Naa-cUbf0
der mit mich überzeugenden Argumenten für alle 100 ng/ml als Zielwert empfiehlt.
Allerdings fahren wir beide ein ganzheitliches Regime, bestehend mindestens aus:
1. veg. Vollwertkost nach Dr.med. Max Otto Bruker und seinem Klassiker "Unsere
Nahrung, unser Schicksal" - http://www.amazon.de/Unsere-Nahrung-Heilbarkeitern%C3%A4hrungsbedingterZivilisationskrankheiten/dp/3891890036/ref=sr_1_1?s=books&ie=UTF8&qid=142550323
3&sr=1-1&keywords=bruker
2. Eine zusätzlich Basis-Versorgung mit den Mixed tablets von LEF https://www.lifeextensioneurope.de/kategorien/multivitamine/life-extension-mixtmtablets-315-tablets-1
3.) täglich zusätzlich zum Vit. D noch Vit.- K - MK 7 mind. 400 mcg (meine Frau) / 600
mcg - von LEF - https://www.lifeextensioneurope.de/kategorien/vitamine/super-kwith-advanced-k2-complex-90-softgels
4.) zusätzlich mind 1000 mg Vitamin C und 500 mg Magnesium
5.) ein Protein - Shake nach Dr. Strunz
6.) mind. 1 Eßlöffel Omega Orange (Leinöl)etc.etc.
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
volker@vonabisw.de
www.vonabisw.de
Von: Manfred G. [mailto:sys34@aon.at]
Gesendet: Mittwoch, 4. März 2015 20:35
An: 'Volker H. Schendel'
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren Fragen an Manfred G.
Hallo Volker
das sind ganz schön hohe Dosierungen , mich würde interessieren auf welchen Vit.D
Wert ihr da kommt (und bei welchen Körpergewicht)
3 Bekannte von mir liegen bei 100 ng/ml mit 50000 IE Kapsel pro Woche (von WLS)
Ich hab auch das Buch von Prof. Spitz über Vit.D und Krebszellen gelesen (sehr
interessant)
dabei sind viele Faktoren dafür verantwortlich , Vitamin D ist ein wichtiges hilfreiches
Teilchen
aber auch Umweltgifte, Ernährung , Bewegung, Psyche usw.
Ich versuche das auch ein wenig von allen Seiten , mir widerstrebt das irgendwie
wegen täglichen Dauereinnahmen, die Sonne scheint auch nicht dauernd
(auch in südlicheren Bereichen nicht) ev. bringt die Technik auch etwas Licht ins
Dunkel (Anhang) geeignete Wohraumbeleuchtung wäre hier ein interessanter
Ansatz , Sommer viel Tageslicht > viel Vit D über natürliche Sonne, Winter wenig
natürliche Sonne (kein Vit D) viel Raumlicht eingeschalten.
das würde sich selbst regeln wenn man geeignete Wohnraumbeleuchtung hätte,
interessant sind auch die Angaben im Anhang bei Versuchen mit der Beleuchtung in
Schulen
auch interessant
viele Tiere (Vögel, Leguane usw.) brauchen für rrtgerechte Haltung UVB Licht , wir
eigentlich auch (zumindest im Winter)
es wird derzeit intensiv geforscht (OLED Raumbeleuchtung usw.)
mfG Manfred
meine Gesundheitsseite
Von: Volker H. Schendel [mailto:volker@vonabisw.de]
Gesendet: Mittwoch, 04. März 2015 09:18
An: 'Manfred G.'
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren Fragen an Manfred G.
danke für die Rückmeldung.
Meine Frau (10.000 tgl.) und ich (2o.ooo tgl.) bleiben auch bei täglich. Bis jetzt habe ich
auch keinerlei Antworten, die Hollis in Frage stellen würden. Vermutlich hat er einfach
recht.
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
volker@vonabisw.de
www.vonabisw.de
Von: Manfred G. [mailto:sys34@aon.at]
Gesendet: Dienstag, 3. März 2015 23:38
An: 'Volker H. Schendel'
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren Fragen an Manfred G.
Hallo Volker
Ok, ich hab hier den gesamten Verlauf nicht richtig mit bekommen , ich dachte es
ginge nur um die Einnahmeintervalle in Bezug zum Vitamin D Wert.(OH25)
Ich hab einige umfangreiche Publikationen durch gesehen , wieviel in der Leber
umgewandelt wird , konnte ich nicht finden , es steht nur das ein Teil in Fettgewebe
und im geringen Maß in Muskelmasse gespeichert wird.
Soweit ich das noch in Erinnerung hab, hatte Bowles seine Eigenversuche mit sehr
hohen Dosierungen längere Zeit täglich vorgenommen (+ zusätzliche Einnahme von
SuperK)
tlw. gab es auch Nebenwirkungen, dann hat er wieder eine Weile unterbrochen und
später wieder weiter gemacht.
Das solche „Roßkuren“ funktionieren, da bin ich mir ziemlich sicher, (so wie die
kurzfristige hoch dosierte Grippetherapie welche ich schon mehrfach getestet habe)
allerdings ist das bei längerfristiger Anwendung schon eine heikle Sache (in einigen
Forenberichten traten bei hoch dosierten Vit.D Anwendungen Beschwerden wie
Herzstolpern, Herzrasen, und tlw. in Studien Vorhofflimmern auf , auch Bowles hatte
kurzzeitig ähnliche Beschwerden) ich denke das ist nicht so leicht zu Händeln , da
man hier auch den Regelmechanismus vom Vit.D aushebelt (die Mineralienversorgung
kommt nicht mit und der provozierte Calciumüberschuß muß mit der richtigen
Dosierung von SuperK in die Richtige Richtung geleitet werden) also viel unbekannte
Grauzone !
ich kann das jetzt nicht beurteilen ob das alles so stimmt, was Hollis heraus gefunden
hat, bei meiner Frau hat das mit Vit.D sehr gut funktioniert
(zufällig tägl. Auffüllung mit 10000IE und Erhaltung mit 5000IE)
erst kürzlich haben wir auf wöchentliche Erhaltung umgestellt , das werden wir jetzt
mal vorsichtshalber wieder tägl. machen (2 Tropfen Vit.D³ a 2500 IE)
und auf weitere Ergebnisse warten, ev. kommen ja noch Meinungen von den Vit.D
Experten.
mfG Manfred
meine Gesundheitsseite
Von: Volker H. Schendel [mailto:volker@vonabisw.de]
Gesendet: Dienstag, 03. März 2015 18:28
An: 'Manfred G.'
Cc: Raimund von Helden; uwegroeber@gmx.net; walach@europa-uni.de
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren Fragen an Manfred G.
Hallo Manfred,
bei
http://www.ncbi.nlm.nih.gov/pubmed/18544622
geht es um Hüftfrakturen, also "off topic" dessen was Prof.
Hollis vertritt.
Im Knochenkontext reicht vermutlich der 25 OH D Blutwert
völlig als Meßgröße aus.
Schon bei der Muttermilch
Prof. Dr. med. Bruce Hollis - Vitamin D Dosing Interval
The Role of the Parent Compound Vitamin D with Respect to
Metabolism and Function: Why Clinical Dose Intervals Can
Affect Clinical Outcomes
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849670/
geht das gar nicht, weil das 25 OH D nicht in die Muttermilch
gelangt. Das kann nur das ursprüngliche Vitamin D 3 =
Colecalciferol. (s. Hollis -Paper auf S.4 ff.)
Und genau dasselbe soll nach Hollis für die präventiven Effekte
von Vitamin D gelten. Also z. B. zur präventiven Krebsabwehr /
Herz Kreislauf / MS etc.etc. muß das Colecalciferol in der
Ursprungsform die konkrete Zellmembran überwinden, was das
an VDBP fest gebundene 25 OH D nach Hollis nicht kann.
Wenn das soweit stimmt, muß wegen der Halbwertzeit von
wahrscheinlich sogar weniger als 24 Std. bei Colecalciferol
zwingend täglich substitutiert werden. Eine wöchentliche
Einmaldosis wäre dann nicht lege artis, um diese
Präventiveffekte zu erzielen.
Das wäre dann wohl ein kleiner Pardigmenwechsel (Thomas S.
Kuhn läßt grüßen) in der Vitamin D 3 Expertenszene - oder? Die "Akkuthese" wäre dann allerdings obsolet - oder? Zusätzlich wären alle Interventionsstudien zu Vitamin D 3
außerhalb des Knochenkontextes nur lege artis als
Sudiendesign angelegt, wenn die Probanden der VerumGruppen täglich mind. 10.000 I. E. Supplement einnehmen oder?
Diese Argumente würden als netten Nebeneffekt auch den
Eigenversuch von Jeff Bowles besser einordnen können oder?
Es gibt dann allerdings das Problem, das der 25 OH D - Spiegel
nur noch maximal als indizieller Wert taugt. Eigentlich müßte
man das umlaufende Colecalciferol unmittelbar messen um
Schlußfolgerungen wie z.B. eine tägliche Dosis von 10.000 I.E.
argumentativ zu rechtfertigen - oder?
Was hältst Du davon?
Anders gefragt:
Wieviel wandelt die Leber eigentlich in Calcidiol um? - 25%, 50 % etc??
Nehmen wir an, der Blutspiegel vor Beginn der Supplementierung läge
bei 60 ng/ml. Dann wäre der Knochenbereich total im grünen Bereich oder?
Nach Hollis könnten dann chronische Krankheiten direkt mit dem
verfügbaren Colecalciferol in den jeweilig zuständigen Zellen verhindert
werden - stimmt das?
Nach Hollis bleibt dieses Vit. D in den Zellen. Kommt also in keiner
umgewandelten Form zurück ins Blut - stimmt das?
Stimmt es, daß im Fettgewebe und Muskelgewebe (wie bisher
angenommen wurde) gar keine Speicherung stattfindet??
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
volker@vonabisw.de
www.vonabisw.de
Von: Manfred G. [mailto:sys34@aon.at]
Gesendet: Dienstag, 3. März 2015 17:27
An: 'Volker H. Schendel'
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren
Hallo Volker
ich kenne 2 Publikationen dazu
eine finde ich leider nicht mehr , die war im vitamindwiki, da wurde eine jährliche,
monatliche wöchentliche und tägliche Einnahme bewertet
die tägliche und wöchentliche Einnahme war am besten, die monatliche Einnahme
etwas schlechter aber auch noch recht gut , die jährliche Einnahme war extrem
schlecht !
die zweite Publikation habe ich gespeichert , hier wurden kaum Unterschiede
zwischen tägl. wöchentlich und monatlich gefunden
http://www.ncbi.nlm.nih.gov/pubmed/18544622
oder auch mit deutscher Übersetzung Link
aus eigenen Erfahrungen weiß ich das eine wöchentliche Dosierung im Sinne
Auffüllung (z.B. nach Holick 8 Wochen mit 50000 IE) oder auch die wöchentliche
Erhaltung
sehr gut funktioniert !
Ob eine tägl. Einnahme nicht auch andere Vorteile hat, kann ich nicht beurteilen,
soweit ich weiß füllt man mit Vitamin D3 Einnahmen nur den Akku auf (optimal um 4060ng/ml) das aktive Vitamin D (1,25) reguliert sich dann von selbst !
die 40 ng/ml Schwelle , wird oft als anzustrebender Wert genannt, da hier
normalerweise genügend Calcium verwertet wird , das kein Calcium mehr von den
Knochen entzogen wird.
(Parathormon nicht erhöht)
Es gibt auch Sonderanwendungen (nach Jeff Bowles) bei denen man durch tägl. hoch
dosierte Vit.D Einnahmen einen gezielte erhöhte Calciumverwertung provoziert, und
zugleich
mit Vit.K (SuperK) das Calcium dem Knochenstoffwechsel zuführt ! (auch mit zus.
Magnesium)
Das fällt aber eher in den Bereich Sondertherapien bei schwerwiegenden Problemen !
(nur etwas für Experten !)
mfG Manfred
meine Gesundheitsseite
Von: Volker H. Schendel [mailto:volker@vonabisw.de]
Gesendet: Dienstag, 03. März 2015 14:49
An: Manfred G.
Betreff: WG: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren
Hallo Manfred,
wie siehst Du das?
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
Von: Volker H. Schendel [mailto:volker@vonabisw.de]
Gesendet: Dienstag, 3. März 2015 14:47
An: 'Uwe Gröber'
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren
Hallo Herr Gröber,
danke für die Rückmeldung. Aber als Teilnehmer an Ihrem Webinar wußte ich das
natürlich.
Ich finde die Aussage von Prof. Hollis zentral, daß von der täglich zugeführten Dosis
Colecalciferol ein bedeutsamer Teil direkt in die nicht knochenrelevaten Zellen
marschiert und also jedenfalls nicht in der Lebe zu Calcidiol umgewandelt wird. Gibt
es dazu auch deutsche Publikationen?
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
volker@vonabisw.de
www.vonabisw.de
Von: Uwe Gröber [mailto:uwegroeber@gmx.net]
Gesendet: Dienstag, 3. März 2015 11:32
An: 'Volker H. Schendel'
Betreff: AW: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren
Lieber Herr Schendel,
wir empfehlen im Rahmen unserer Publikationen (Nutrients, 2015, Dermatoendocrinology,
2013, etc.) nach dem Auffüllen des 25(OH)D-Status mit folgender Formel:
40x (Soll - Ist in nmol/l) x kg KG = VDI verteilt auf 7-10 Tage
eine regelmäßige täglich Einnahme von 40-60 IE VD pro kg KG pro Tag (Zielbereich:
25(OH)D 40-60 ng/ml).
Für den Knochen sind mindestens für die optimale Calciumresorption und -verwertung
25(OH)D-Spiegel von über 32 ng/ml notwendig.
Herzliche Grüße aus Essen
Uwe Gröber
Von: Volker H. Schendel [mailto:volker@vonabisw.de]
Gesendet: Dienstag, 3. März 2015 10:42
An: uwegroeber@gmx.net
Betreff: WG: Die Notwendigkeit, Vitamin D 3 zwingend täglich zu supplementieren
Lieber Herr Gröber,
wenn ich die Forschungsergebnisse von Prof. Dr. Hollis (s.u.)
zugrundelege mit der 24 - Std. - Halbwertzeit für das durch die Sonne,
Fischkonsum oder Supplement dem Körper zur Verfügung gestellte
Colecalciferol,
ist dann eine nur wöchentliche Gabe noch vertretbar?
Nehmen wir 20.000 I. E. (z.B. eine Kapsel Dekristol). Einnahme am
Montag. Am Dienstag wegen der Halbwertzeit noch wieviel?
Wieviel wandelt die Leber eigentlich in Calcidiol um? - 25%, 50 % etc??
Nehmen wir an, der Blutspiegel vor Beginn der Supplementierung läge
bei 60 ng/ml. Dann wäre der Knochenbereich total im grünen Bereich oder?
Nach Hollis könnten dann chronische Krankheiten direkt mit dem
verfügbaren Colecalciferol in den jeweilig zuständigen Zellen verhindert
werden - stimmt das?
Nach Hollis bleibt dieses Vit. D in den Zellen. Kommt also in keiner
umgewandelten Form zurück ins Blut - stimmt das?
Hier:
http://www.vonabisw.de/43.html
gibt es:
Dr. Bruce Hollis - Vitamin D Dosing Interval
https://www.youtube.com/watch?v=FbheaULwRAk
http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi13.mp4
http://www.nysafp.org/other/Vitamin%20D_Hollis%20%5BCompatibility%
20Mode%5D.pdf
http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi14.pdf
http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi17.pdf
Vitamin D supplementation in pregnancy & breastfeeding - effectiveness
and safety. Dr Bruce Hollis
https://www.youtube.com/watch?v=O0elnh4D08g
http://d.mp3vhs.de/vonabisw/Vitamind3/Wi/Wi15.mp4
Mit freundlichen Grüßen
Volker H. Schendel – Ministerialrat a. D.
Freier Wissenschaftsjournalist
Kleiststr. 45
D - 30916 Isernhagen
Tel.: 0511 / 640 9 136
Von: CustomerService@lifeextension.com [mailto:CustomerService@lifeextension.com]
Gesendet: Donnerstag, 5. März 2015 20:21
An: volker@vonabisw.de
Betreff: Case:[3351885] - WG: Dr. Bruce Hollis - Vitamin D Dosing Interval - it must be
daily?
Dear Volker Schendel ,
Thank you for your recent correspondence.
Life Extension certainly agrees that daily administration of vitamin D3 has the best efficacy in
maintaining levels within a narrow range, and avoiding peaks and troughs associated with
intermittent dosing.
Since vitamin D is important for a wide variety of cells in the body, it is critical to maintain
sufficient vitamin D availability. Dr. Hollis’ research seems to validate this idea.
Please keep in mind that Life Extension cannot comment on whether it is “medical
malpractice” to use a weekly dosing instead of daily supplementation. Nevertheless, we feel
that daily dosing is ideal to ensure consistent availability of vitamin D to target tissues.
Please let us know if there is anything else we can do for you. If you have any additional
questions, please e-mail us or call the advisor helpline at (800) 226-2370; international
customers dial 001-954-202-7660.
Thank you for choosing Life Extension as your trusted source of health information.
Please make sure Case:[3351885] is in the subject line of all correspondence.
For Longer Life,
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History of Vitamin D
Historical Review
Man is reported to have been aware since early antiquity of the substance we now
know as vitamin D. The first scientific description of a vitamin D-deficiency, namely
rickets, was provided in the 17th century by both Dr. Daniel Whistler (1645) and
Professor Francis Glisson (1650). The major breakthrough in understanding the
causative factors of rickets was the development in the period 1910 - 1930 of nutrition
as an experimental science and the appreciation of the existence of vitamins.
Considering the fact that now we accept that the biologically active form of vitamin D,
namely 1a,25(OH)2-vitamin D3, is a steroid hormone, it is somewhat ironic that vitamin
D, through a historical accident, became classified as a vitamin. It was in 1919/20 that
Sir Edward Mellanby, working with dogs raised exclusively indoors (in the absence of
sunlight or ultraviolet light), devised a diet that allowed him to unequivocally establish
that the bone disease, rickets was caused by a deficiency of a trace component
present in the diet. In 1921 he wrote, "The action of fats in rickets is due to a vitamin or
accessory food factor which they contain, probably identical with the fat-soluble
vitamin." Furthermore, he established that cod liver oil was an excellent antirachitic
agent.
Shortly thereafter E.V. McCollum and associates observed that by bubbling oxygen
through a preparation of the "fat-soluble vitamin" they were able to distinguish
between vitamin A ( which was inactivated) and vitamin D (which retained activity). In
1923 Goldblatt and Soames clearly identified that when a precursor of vitamin D in the
skin (7-dehydrocholesterol) was irradiated with sunlight or ultraviolet light, a
substance equivalent to the fat-soluble vitamin was produced. Hess and Weinstock
confirmed the dictum that "light equals vitamin D". They excised a small portion of
skin, irradiated it with ultraviolet light, and then fed it to groups of rachitic rats. The
skin that had been irradiated provided an absolute protection against rickets, whereas
the unirradiated skin provided no protection whatsoever; clearly, these animals were
able to produce by uv irradiation adequate quantities of "the fat-soluble vitamin",
suggesting that it was not an essential dietary trace constituent. In parallel studies,
Steenbock and Black at the Biochemistry Department of the University of Wisconsin
found that rat food which was irradiated with ultra violet light also acquired the
property of being antirachitic. However, because of the rapid rise of the science of
nutrition -- and the discovery of the families of water-soluble and fat-soluble vitamins -
- it rapidly became firmly established that the antirachitic factor was to be classified as
a vitamin.
The chemical structures of the vitamins D were determined in the 1930s in the
laboratory of Professor Adolf Otto Reinhold Windaus at the University of Göttingen in
Germany. Professor Windaus had some 55 doctoral and postdoctoral chemists
working on the 'vitamin D project'. Professor Windaus received a Nobel Prize in
Chemistry in 1928 for his work on sterols and their relationship to vitamins.
Vitamin D2 which could be produced by ultraviolet irradiation of ergosterol was
chemically characterized in 1932. Vitamin D3 was not chemically characterized until
1936 when it was shown to result from the ultraviolet irradiation of 7dehydrocholesterol. Virtually simultaneously, the elusive antirachitic component of
cod liver oil was shown to be identical to the newly characterized vitamin D3. These
results clearly established that the antirachitic substance vitamin D was chemically a
steroid, more specifically a seco-steroid.
Key reference citations:
Whistler, D. Morbo puerili Anglorum, quem patrio idiomate indigenae vocant The
Rickets. Lugduni Batavorum 1-13 (1645).
Glisson, F. De Rachitide sive morbo puerili, qui vulgo The Rickets diciteur, London 1416 (1650).
Glisson, F. A treatise of the rickets being a disease common to children. London 1-373
(1668).
Mellanby, E. and Cantag, M.D. Experimental investigation on rickets. Lancet 196:407412 (1919).
Mellanby, E. Experimental rickets. Medical Research (G.B.), Special Report Series
SRS-61:1-78 (1921).
Hess, A. Influence of light on the prevention of rickets. Lancet 2:1222 (1922).
McCollum, E.V., Simmonds, N., Becker, J.E. and Shipley, P.G. Studies on experimental
rickets. XXI. An experimental demonstration of the existence of a vitamin which
promotes calcium deposition. J. Biol. Chem. 53:293-312 (1922).
Goldblatt, H. and Soames, K.N. A study of rats on a normal diet irradiated daily by the
mercury vapor quartz lamp or kept in darkness. Biochem. J. 17:294-297 (1923).
Steenbock, H. and Nelson, M. T. Fat-soluble vitamins. XIX. The induction of calcifying
properties in a rickets-producing ration by radiant energy. Methods Enzymol. 62:209216 (1924).
Steenbock, H. The induction of growth promoting and calcifying properties in a ration
by exposure to light. Science 60:224-225 (1924).
Windaus, A., Linsert, O. Luttringhaus, A. and Weidlinch, G. Uber das krystallistierte
Vitamin D2. Justis. Liebigs. Ann. Chem. 492:226-231 (1932).
Brockmann, H. Die Isolierung des antirachitischen Vitamins aus Thunfischleberol. H.S.Zeit. Physiol. Chem. 241:104-115 (1936).
Crowfoot-Hodgkin, D., Webster, M.S. and Dunitz, J.D. Structure of calciferol. Chem.
Industry 1148-1149 (1957).
Solecki, R.S. Shanidar: The Humanity of Neanderthal Man, New York: Knopf. pp. 1-252
(1971).
Article was Last Updated: November 2011.
Chemistry
Chemistry of Vitamin D
The structures of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol)
and their provitamins are presented in Figure 1 on the right.
Vitamin D is a generic term and indicates a molecule of the general structure shown for rings
A, B, C, and D with differing side chain structures. The A, B, C, and D ring structure is
derived from the cyclopentanoperhydrophenanthrene ring structure for steroids. Technically
vitamin D is classified as a seco-steroid. Seco-steroids are those in which one of the rings has
been broken; in vitamin D, the 9,10 carbon-carbon bond of ring B is broken, and it is
indicated by the inclusion of "9,10-seco" in the official nomenclature.
Vitamin D (calciferol) is named according to the revised rules of the International Union of
Pure and Applied Chemists (IUPAC). Because vitamin D is derived from a steroid, the
structure retains its numbering from the parent compound cholesterol. Asymmetric centers are
designated by using the R,S notation; the configuration of the double bonds are notated E for
"entgegen" or trans, and Z for "zuzammen" or cis. Thus the official name of vitamin D3 is
9,10-seco(5Z,7E)-5,7,10(19)cholestatriene-3b-ol, and the official name of vitamin D2 is 9,10seco(5Z,7E)-5,7,10(19), 22-ergostatetraene-3b-ol.
Vitamin D3 can be produced photochemically by the action of sunlight or ultraviolet light
from the precursor sterol 7-dehydrocholesterol which is present in the epidermis or skin of
man and most higher animals. The chief structural prerequisite of a provitamin D is that it be
a sterol with a D5,7 diene double bond system in ring B (Figure 2 to the left). The conjugated
double bond system in this specific location of the molecule allows the absorption of light
quanta at certain wavelengths in the UV range; this can readily be provided in most
geographical locations by natural sunlight (or UV-B). This initiates a complex series of
transformations ( partially summarized above in Fig. 1) that ultimately results in the
appearance of vitamin D3. Thus, it is important to appreciate that vitamin D3 can be
endogenously produced and that as long as the animal (or human) has access on a regular
basis to sunlight there is no dietary requirement for this vitamin.
References
Crowfoot-Hodgkin, D., Webster, M.S. and Dunitz, J.D. Structure of Calciferol. Chem.
Industry 1148-1149 (1957).
Calverley, M.J. and Jones, G. Vitamin D. In: Antitumor Steroids, edited by Blickenstaff, R.T.
San Diego: Academic Press, pp. 193-270 (1992).
Ikekawa, N. and Ishizuka, S. Molecular structure and biological activity of vitamin D
metabolites and their analogs. In: Molecular Structure and Biological Activity of Steroids.
Boca Raton: CRC Press, pp. 293-316 (1993).
Zhu, G.-D and Okamura, W.H. Synthesis of vitamin D (calciferol). Chem. Rev. 95:1877-1952
(1995).
Ma,Y.; Khalifa,B.; Yee,Y.K.; Lu,J.; Memezawa,A.; Savkur,R.S.; Yamamoto,Y.;
Chintalacharuvu,S.R.; Yamaoka,K.; Stayrook,K.R.; Bramlett,K.S.; Zeng,Q.Q.;
Chandrasekhar,S.; Yu,X.P.; Linebarger,J.H.; Iturria,S.J.; Burris,T.P.; Kato,S.; Chin,W.W.;
Nagpal,S. Identification and characterization of noncalcemic, tissue-selective,
nonsecosteroidal vitamin D receptor modulators J. Clin.Invest.116:892-904 (2006).
Zhang,F.; Nunes,M.; Segmuller,B.; Dunphy,R.; Hesse,R.H.; Setty,S.K. Degradation
chemistry of a Vitamin D analogue (ecalcidene) investigated by HPLC-MS, HPLC-NMR and
chemical derivatization J. Pharm. Biomed. Anal. 40: 850-863 (2006).
Article Last Updated: November 2011.
Nutritional Aspects of Vitamin D
Introduction
A "vitamin" by definition is a substance regularly required by the body in small
amounts but which the body cannot make and is, therefore, required to be supplied in
the daily diet. Technically the molecular species classified as vitamin D3 is not really a
vitamin because it can be produced by exposure of the skin to sunlight (see section
on Chemistry). However, for nutritional and public health reasons, vitamin D3
continues to be classified officially as a vitamin (see section on History of Vitamin D).
Nutritional Aspects
The World Health Organization had responsibility for defining the "International Unit"
of vitamin D3. Their most recent definition, provided in 1950 states that "the
International Unit of vitamin D recommended for adoption is the vitamin D activity of
0.025 micrograms (25 nanograms) of the international standard preparation of
crystalline vitamin D3". Thus, 1.0 IU of vitamin D3 is 25 nanograms, which is
equivalent to 65.0 pmoles. With the discovery of the metabolism of vitamin D3 to other
active seco-steroids, particularly 1α,25(OH)2D3, it was recommended that 1.0 unit of
1α,25(OH)2D3 be set equivalent in molar terms to that of the parent vitamin D3. Thus,
1.0 unit of 1α,25(OH)2D3 has been operationally defined to be equivalent to 65 pmoles.
The vitamin D requirement for healthy adults has never been precisely defined. Since
vitamin D3 is produced in the skin after exposure to sunlight, the human does not
have a requirement for vitamin D when sufficient sunlight is available. However,
vitamin D does become an important nutritional factor in the absence of sunlight. It is
known that a substantial proportion of the U.S. population is exposed to quite
suboptimal levels of sunlight especially during the winter months; it is likely that
during these intervals that a regular dietary supply of vitamin D3 should be provided.
In addition to geographical and seasonal factors, ultraviolet light from the sun may
also be blocked by air pollution. The tendency to wear clothes, to live in cities where
tall buildings block adequate sunlight from reaching the ground, to live indoors, to use
synthetic sunscreens that block ultraviolet rays, and to live in geographical regions of
the world that do not receive adequate sunlight, all contribute to the inability of the
skin to biosynthesize sufficient amounts of vitamin D3. Under these conditions
vitamin D becomes a true vitamin in that it must be supplied in the diet on a regular
basis.
Since vitamin D3 can be endogenously produced by the body and since it is retained
for long periods of time by vertebrate tissue, it is difficult to determine with precision
the minimum daily requirements for this seco-steroid. The requirement for vitamin D is
also known to be dependent on the concentration of calcium and phosphorus in the
diet, the physiological stage of development, age, sex, degree of exposure to the sun,
and the amount of pigmentation in the skin.
In November of 2010, , the Institute of Medicine's (IOM) special committee of 15
experts from the US and Canada issued its report for the citizens of both countries
defining the formal Dietary Reference Intakes (average daily doses) of vitamin D and
calcium required for good health. Their recommendation for vitamin D is that from
ages 1 to 70, people need to consume no more than 600 International Units (IU) per
day. For individuals 70 or older, the recommendation is 800 IU/day to maintain strong
bone. This is only a modest adjustment of the very conservative advice rendered by
the 1997 IOM committee of 200 – 600 IU/day, depending upon age.
In the United States, adequate amounts of vitamin D can readily be obtained from the
diet and from casual exposure to sunlight. However, in some parts of the world where
food is not routinely fortified and sunlight is often limited during some periods of the
year, obtaining adequate amounts of vitamin D becomes major problem. The 13th and
14th Vitamin D Workshops reported in white papers that two thirds of the world
population has a vitamin D deficiency.
Vitamin D3 versus Vitamin D2
For decades since the determination of the chemical structures of vitamin D3 and
vitamin D2 in the 1930's it has been assumed that both vitamins had equivalent
biological activity in humans. This was based on biological determination in rats of
their comparative antirachitic activity. However in 1997, the IOM vitamin D reference
intake publication for vitamin D, serum 25-hydroxyvitamin D [25(OH)D], rather than
antirachitic activity, was defined as the functional indicator of vitamin D status.
In a 2010 paper by R. Heaney and coworkers it was reported that vitamin D3 is
approximately 87% more potent in raising and maintaining serum 25(OH)D levels than
was vitamin D2. In addition, vitamin D3 produced a 2- to 3-fold greater storage of
vitamin D than does equimolar D2. For
neither was there evidence of sequestration in fat, as had been postulated for doses in
this range.
Thus the authors felt that given the greater potency and lower cost, vitamin D3 should
be the preferred choice for correcting vitamin D deficiency in humans.
Food Sources
Animal products constitute the bulk source of vitamin D that occurs naturally in
unfortified foods. Salt water fish such as herring, salmon, sardines, and fish liver oils
are good sources of vitamin D3. Small quantities of vitamin D3 are also derived from
eggs, veal, beef, butter, and vegetable oils while plants, fruits, and nuts are extremely
poor sources of vitamin D. In the United States, artificial fortification of foods such as
milk (both fresh and evaporated), margarine and butter, cereals, and chocolate mixes
help in meeting the RDA recommendations.
References:
Heaney,R.P.; Recker,R.R.; Grote,J.; Horst,R.L.; Armas,L.A. Vitamin D3 is more potent
than vitamin D2 in humans J.Clin.End.Metab.93: 447-452 (2011).
Vieth, R.., Why the minimum desirable serum 25-hydroxyvitamin D level should be 75
nmol (30 ng/ml), Best Practice & Research- Clinical endocrinology & Metabolism,
25:681-692 (2011).
Bouillon, R.., Why modest but widespread improvement of vitamin D status is the best
strategy. Best Practice & Research- Clinical endocrinology & Metabolism, 25:693692702 (2011).
Institute of Medicine (2011) Dietary Reference Intakes for Calcium and Vitamin D.
Washington, DC: National Academies Press.
Norman, A.W. and Bouillon, R. Vitamin D nutritional policy needs a vision for the
future. Exp. Biol. Med. 235:1034-1045 (2010).
Henry, H.L., Bouillon, R., Norman, A.W., Gallagher, J.C., Lips, P., Heaney, R.P., Vieth,
R.,Pettifor, J.M., Dawson-Hughes, B., Lamberg-Allardt, C.J., and Ebeling, P.R. 14th
Vitamin D Workshop consensus on vitamin D nutritional guidelines. J. Steroid
Biochem. Mol. Biol. 121:4-6 (2010).
Norman, A.W. From Vitamin D to hormone D: Fundamentals of the vitamin D endocrine
system essential for good health. Amer. J. Clin. Nutrition. 88(2):4915-4995 (2008).
Vieth, R., Bischoff-Ferrari, H., Boucher, B., Dawson-Hughes, B., Garland, C., Heaney,
R., Holick, M., Hollis, B., Lamberg-Allardt, C., McGrath, J., Norman, A., Scragg, R.,
Whiting, S., Willett, W., and Zittermann, A. The urgent need to recommend an intake of
vitamin D that is effective. Am. J. Clin. Nutr. 2007 85: 649-650 (2007).
Norman, A.W., Henry, H.L. Vitamin D In: Present Knowledge in Nutrition, 9th Edition,
(Bownam, B.A. and Russell, R.M.), International Life Sciences Institute, Washington
D.C. Chapter 12, pp 198-210 (2006).
Subcommittee on the Tenth Edition of the RDAs, Food & Nutrition Board, Commission
on Life Sciences and National Research Council. Recommended dietary allowances,
Washington, D.C.: National Academy Press. Ed. 10th pp. 1-285 (1989).
Dietary reference intakes for calcium, magnesium, phosphorus, vitamin D, and
fluoride. Food and Nutrition Board, Institute of Medicine. Washington, DC: National
Academy Press (1997).
Article Last Updated: November 2011.
Biochemistry and Physiology of Vitamin D
Biochemistry and Physiology of the Vitamin D Endocrine System
A detailed study of the biochemical mode of action of the fat-soluble vitamin D was not
possible until the availability in the 1960s of preparations of high specific activity radioactive
vitamin D. As a consequence of efforts in several laboratories a new model emerged in the
late 1960’s to describe the biological mechanisms of action of vitamin D3. This model is
based on the concept that, in terms of its structure and mode of action, vitamin D is similar to
the classic steroid hormones, e.g. aldosterone, testosterone, estradiol, progesterone, cortisol,
and ecdysterone.
As summarized in the figure on the left, the existence of the vitamin D endocrine system is
now firmly established.
The key elements of the vitamin D endocrine system include the following:
(a) In the skin, photoconversion of 7-dehydrocholesterol to vitamin D3 or dietary intake
of vitamin D3.
(b) Metabolism of vitamin D3 by the liver to 25(OH)D3; this the major form of vitamin D
circulating in the blood compartment.
(c) Functioning of the kidney as an endocrine gland, to metabolize 25(OH)D3 to produce
the two principal dihydroxylated vitamin D metabolites, namely 1a,25(OH)2D3 and
24R,25(OH)2D3.
(d) Systemic transport of the dihydroxylated metabolites 1a,25(OH)2D3 and
24R,25(OH)2D3 to distal target organs by the plasma vitamin D binding protein (DBP).
(e) Binding of the dihydroxylated metabolites, particularly 1a,25(OH)2D3, to a receptor a
that is localized in the nucleus and plasma membrane of t the target organs followed by
the subsequent generation of appropriate biological responses (both genomic and rapid
responses).
An additional key component in the operation of the vitamin D endocrine system is the
plasma vitamin D binding protein (DBP) that carries the hydrophobic vitamin D3 and all of its
metabolites through the circulatory system to their various target organs. A target organ, by
definition will have the vitamin receptor, the VDR.
Since 1971, research efforts have largely focused upon understanding how 1a,25(OH)2D3
generates biological responses. From 1960 – 2021approximately 25,000 scientific papers
were published that used the term vitamin D either in the title or abstract. By comparison, the
biological actions of 24R,25(OH)2D3 have been relatively less studied. However, evidence
has been presented to support the view that the combined presence of both 1a,25(OH)2D3 and
24R,25(OH)2D3 are required to generate the complete spectrum of biological responses
attributable to the parent vitamin D.
Metabolism of Vitamin D
Thus, vitamin D3 is, in reality, a prohormone and is not known to have any intrinsic biological
activity itself. It is only after vitamin D3 is metabolized, first into 25(OH)D3 in the liver, and
then into 1a,25(OH)2D3 and 24R,25(OH)2D3 by the kidney, that biologically active molecules
are produced. In toto some 37 vitamin D3 metabolites have been isolated and chemically
characterized.
The key kidney enzymes, the 25(OH)D3-1-hydroxylase and the 25(OH)D3-24-hydroxylase, as
well as the liver vitamin D3-25-hydroxylase, are all known to be cytochrome P-450 mixedfunction oxidases. Both of the renal enzymes are localized in mitochondria of the proximal
tubules of the kidney. Mixed-function oxidases use molecular oxygen as the oxygen source
instead of water. Mitochondrial mixed-function oxidases are composed of three proteins that
are integral components of the mitochondrial membrane; they are renal ferredoxin reductase,
renal ferredoxin, and cytochrome P-450.
The most important point of regulation of the vitamin D endocrine system occurs through the
stringent control of the activity of the renal 1-hydroxylase. In this way the production of the
hormone 1a,25(OH)2D3 can be modulated according to the calcium and other endocrine needs
of the organism. The chief regulatory factors are 1a,25(OH)2D3 itself, parathyroid hormone
(PTH), and the serum concentrations of calcium and phosphate. The most important
determinant of the 1-hydroxylase activity is the vitamin D status of the animal. When
circulating concentrations of 1a,25(OH)2D3 are low, production of 1a,25(OH)2D3 by the
kidney is high, and when circulating concentrations of 1a,25(OH)2D3 are high, the output of
1a,25(OH)2D3 by the kidney is sharply reduced.
Actions of the vitamin D receptor:
1a,25(OH)2D3working with its VDR is known to selectively activate ≈ 3% of the some 22,000
genes of the human genome. The regulation of gene transcription by 1a,25(OH)2D3 is known
to be mediated by interaction of this ligand with its personal nuclear receptor protein, termed
the VDR. The VDR is known to occur in over 35 different cell types. 1a,25(OH)2D3 when
bound to the VDR regulates the transcription of numerous proteins. In addition, the VDR is
known to localize with the plasma membrane of the target cell where it initiates rapid
responses (e.g. opening of chloride or calcium channels or stimulating exocytosis). A number
of excellent articles have appeared describing the current understanding of how the VDR
regulates both gene transcription and rapid responses.
References
References for lay persons:
Norman, A.W., Henry, H.L. Vitamin D In: Present Knowledge in Nutrition, 9th Edition,
(Bownam, B.A. and Russell, R.M.), International Life Sciences Institute, Washington D.C.
Chapter 12, pp 198-210 (2006).
Comprehensive references to review articles covering all aspects of vitamin D with particular
emphasis on 1a,25(OH)2D3:
Vitamin D, 3rd Ed. Edited by Feldman, D., Pike, J.W, Adams, J.S. San Diego, Academic
Press, pp. 1-2081 (2011).
Henry, H.L., Regulation of vitamin D metabolism, Best Practice & Research- Clinical
endocrinology & Metabolism, 25:531-541 (2011).
Haussler, M.R., Jurutka, P.W., Mizwicki, M., & Norman, A.W., Vitamin D receptor (VDR)mediated actions of 1a,25(OH)2-vitamin D3: Genomic and non-genomic mechanisms. Best
Practice & Research- Clinical endocrinology & Metabolism, 25:543-559 (2011).
Bouillon,R.; Carmeliet,G.; Verlinden,L.; van Etten,E.; Verstuyf,A.; Luderer,H.F.; Lieben,L.;
Mathieu,C.; Demay,M., Vitamin D and human health: Lessons from vitamin D receptor null
mice, Endocr.Rev.6: 726-776 (2008).
Pike,J.W.; Meyer,M.B.; Watanuki,M.; Kim,S.; Zella,L.A.; Fretz,J.A.; Yamazaki,M.;
Shevde,N.K., Perspectives on mechanisms of gene regulation by 1,25-dihydroxyvitamin D3
and its receptor, J.Steroid Biochem.Mol.Biol., 103: 389-395 (2007).
Norman, A.W. Vitamin D Receptor (VDR): New assignments for an already busy receptor.
Endocrinology 147: 5542-5548 (2006).
Bouillon, R., Okamura, W.H. and Norman, A.W. Structure-function relationships in the
vitamin D endocrine system. Endocr. Rev. 16:200-257 (1995).
Disease and Vitamin D
The figure to the right summarizes the contributions of vitamin D to good health. Over
the past decade, four lines of investigation have collectively yielded striking new
insights into the many newly appreciated actions of vitamin D. These include the
following: (i) a broad range of molecular and cellular effects of 1a,25(OH)2D3; (ii)
experimental studies in the VDR-KO mouse model; (iii) several large observational
epidemiological studies in subjects with variable nutritional vitamin D status ; and (iv)
prospective randomized intervention studies with vitamin D.
Consequently, evidence has accumulated that beside the calcium homeostasis
system (intestine, kidney, bone and the parathyroid gland) there are five additional
physiological systems where VDR + 1α,25(OH)2D generates essential biological
responses; see the first column under the header of Physiological Systems.. These
include the immune system (both innate and adaptive), pancreas and glucose and fat
metabolism, heart-cardiovascular, muscle and brain systems as well as the control of
the cell cycle in virtually all cells and thus of the disease process of cancer
Acting through the VDR, 1a,25(OH)2D can produce a wide array of favorable biological
effects that collectively are projected to contribute to the improvement of human
health.; see the second column under the header Biological Responses. The third
column under the header VitaminD Deficiency Associated Diseases identifies for each
physiological system some of the disease states that are associated with an
inadequate vitamin D nutritional status. The supporting information for this figure
have been published in Norman, A.W. and Bouillon, R. Vitamin D nutritional policy
needs a vision for the future. Exp. Biol. Med. 235:1034-1045 (2010).
Conceptually, human clinical disorders related to vitamin D can be considered as
those arising because of (a) altered availability of vitamin D; (b) altered conversion of
vitamin D3 to 25(OH)D3; (c) altered conversion of 25(OH)D3 to 1a,25(OH)2D3 and/or
24R,25(OH)2D3; (d) variations in end organ responsiveness to 1a,25(OH)2D3 or possibly
24R,25(OH)2D3; and (e) other conditions of uncertain relation to vitamin D. Thus, the
clinician/nutritionist/biochemist is faced with a problem, in a diagnostic sense, of
identifying parameters of hypersensitivity, antagonism, or resistance (including
genetic aberrations) to vitamin D or one of its metabolites as well as identifying
perturbations of metabolism that result in problems in production and/or delivery of
the hormonally active form, 1a,25(OH)2D3. A detailed consideration of this area is
beyond the scope of this presentation. There are many scientific publications; a list of
recent summary articles are available at the end of this presentation.
Drug Forms of 1a,25(OH)2D3
As a consequence of the significant scientific advances in the understanding of how
vitamin D generates biological responses [principally via 1a,25(OH)2D3], a number of
new drug forms of 1a,25(OH)2D3 have been generated by pharmaceutical companies.
The table below summarizes these new drugs and the relevant pharmaceutical
company, and identifies the clinical circumstance for which their use has been
authorized.
Drug Forms of Vitamin D Analogs
Compound
Name
Generic Name
Commerci
al Name
Pharmaceutical
Company
Effective
Daily Dose Approv
(microgram ed Use
s)*
Compound
Name
Generic Name
Commerci
al Name
Pharmaceutical
Company
Effective
Daily Dose Approv
(microgram ed Use
s)*
1α,25(OH)2D3
CALCITRIOL
ROCALTR ROFFMAN-LA
OL
ROCHE
0.5-1.0
RO,
HP, Ob
1α,25(OH)2D3
CALCITRIOL
CALCIJEX ABBOTT
0.5 (i.v.)
HC
1α,25(OH)2-19PARICALCITOL
nor-D2
ZEMPLAR ABBOTT
2.8-7 (eod) SHP
1α,24(OH)2D3
BONALFA
TACALCITOL
TEIJIN LTD.JAPAN
1α,24S(OH)222-ene-24CALCIPOTRIENE
cyclopropyl-D3
DOVONEX LEO-DENMARK
1α,24S(OH)222-ene-24CALCIPOTRIENE
cyclopropyl-D3
DOVONEX
WESTWOODSQUIBB
40-80
(topical)
PP
40-80
(topical)
PP
40-80
(topical)
PP
1α-OH-D3
ALFACALCIDOL
ONE-ALFA LEO-DENMARK
1-2
RO,
HP, O,
VDRR
1α-OH-D3
ALFACALCIDOL
ALPHA-D3 TEVA-ISRAEL
0.25-1.0
RO, O,
HC, HP
1α-OH-D3
ALFACALCIDOL
ONEALFA
0.25-1.0
RO, O
1α-OH-D3
ALFACALCIDOL
ONEALFA CHUGAI-JAPAN
0.25-1.0
RO, 0
1α-OH-D2
HECTORO
DOXERCALCIFEROL
GENZYME
L
10
4x/WEEK
(i.v.)
SHP
25(OH)D3
CALCIFEDIOL
CALDERO
ORGANON-USA
L
50-500
RO
25(OH)D3
CALCIFEDIOL
ROUSSELDEDROGY
UCLAFL
FRANCE
50-500
RO
200-1000
RO
TEIJIN LTD.JAPAN
DIHYDROTACHYSTE HYTAKER
10,19WINTHROP
OL
dihydrotachyste ROL3
Compound
Name
Generic Name
Commerci
al Name
Pharmaceutical
Company
Effective
Daily Dose Approv
(microgram ed Use
s)*
rol3
1α,25(OH)2-22MAXACALCITOL
oxa-D3
OXAROL
5-10
3x/WEEK
(i.v.)
SHP
1α,25(OH)226,27-F6-D3
FALECALCITRIOL
SUMMITOMO
FULSTAN PHARMACEUTIC
0.15-0.34
TABLETS ALSJAPAN
HC,
SHP,
RO
FALECALCITRIOL
TAISHO
HORNEL PHARMACEUTIC
0.15-0.35
TABLETS ALSJAPAN
HC,
SHP,
RO
1a,25(OH)226,27-F6-D3
CHUGAI-JAPAN
The key to the approved uses of the vitamin D analogs is as follows: RO = renal
osteodystrophy, O = postmenopausal osteoporosis; PP = plaque psoriasis; HC =
hypocalcemia (frequently present in patients with renal osteodystrophy who are
subjected to hemodialysis); HP = hypoparathyroidism and associated hypocalcemia
which may frequently be encountered in patients with hypoparathyroidism,
pseudohypoparathyroidism or in circumstances of post-surgical hypoparathyroidism;
SHP = secondary hyperparathyroidism associated with renal osteodystrophy; VDRR =
vitamin D-resistant rickets.
a
Oral dose unless otherwise indicated; eod = every other day
b
The use of Rocaltrol for postmenopausalosteoporosis is approved in Argentina,
Australia, Austria, Czech Republic, Columbia, India, Ireland, Italy, Japan, Malaysia,
Mexico, New Zealand, Peru, Philippines, South Korea, South Africa, Switzerland,
Turkey, and the United Kingdom.
NOTE: This Table 1 was published in Present Knowledge in Nutrition, 9th edition by A.
W. Norman & H..L. Henry (Bohman, B. A and Russell, R. M.) International Life Sciences
Institute, Washington D.C.; Chapter 12, pp. 198- 210 (2006).
References
Vitamin D, 3rd Ed. Edited by Feldman, D., Pike, J.W, Adams, J.S. San Diego, Academic
Press, pp. 1-2081 (2011).
Holick, M.F., Binkley, N.C., Bischoff-Ferrari, H.A., Gordon, C.M., Hanley, D. A., Heaney,
R. P., Murad, M. H., and Weaver, C. M., Evaluation, treatment and prevention of vitamin
D deficiency: An Endocrine Society clinical practice guideline. J. Clin. Endoctinol.
Metab. 96: 1911-1930 (2011).
Lappe, J.M., The role of vitamin D in human health: A paradigm shift, J. EvidenceBased Complementary & Alternative Medicine, 16:58-72 (2011).
Haussler, M.R., Jurutka, P.W., Mizwicki, M., & Norman, A.W., Vitamin D receptor (VDR)mediated actions of 1a,25(OH)2-vitamin D3: Genomic and non-genomic mechanisms.
Best Practice & Research- Clinical endocrinology & Metabolism, 25:543-559 (2011).
Henry, H.L., Regulation of vitamin D metabolism, Best Practice & Research- Clinical
endocrinology & Metabolism, 25:531-541 (2011).Best Practice & Research- Clinical
endocrinology & Metabolism, 25:543-559 (2011).
Bouillon,R.; Carmeliet,G.; Verlinden,L.; van Etten,E.; Verstuyf,A.; Luderer,H.F.;
Lieben,L.; Mathieu,C.; Demay,M., Vitamin D and human health: Lessons from vitamin
D receptor null mice, Endocr.Rev.6: 726-776 (2008).
Melamed, ML, Michos, ED, Post, W, Astor, B. 25-hydroxyvitamin D levels and the risk
of mortality in the general population. 6 168: 1629-1637, 2008.
Pike,J.W.; Meyer,M.B.; Watanuki,M.; Kim,S.; Zella,L.A.; Fretz,J.A.; Yamazaki,M.;
Shevde,N.K., Perspectives on mechanisms of gene regulation by 1,25dihydroxyvitamin D3 and its receptor, J.Steroid Biochem.Mol.Biol., 103: 389-395
(2007).
Bouillon, R, Verstuyf, A, Mathieu, C, Van, CS, Masuyama, R, Dehaes, P, Carmeliet, G.
Vitamin D resistance.6 20: 627-645, 2006,
H.P. and Norman, A.W. The role of the vitamin D endocrine system in health and
disease. New Engl. J. Med. 320:980-991 (1989).
Vitamin D and Milk
Prepared by Professor Anthony W. Norman;
Department of Biochemistry & Biomedical Sciences
University of California, Riverside CA 92521
(December 12, 2000 & updated in 2011)
Purpose of this statement:
The objective of this presentation is to provide a brief descriptions of vitamin D's chemistry,
nutritional importance, sources, production and presence in milk. This will first require a
review of the biological and nutritional background on vitamin D, which is a precursor of a
steroid hormone [1a,25(OH)2D3] in higher animals, including humans.
What is a vitamin?
A vitamin is a substance (a specific organic molecule) whose presence is crucial to the normal
every day life and functions of animals. However vitamins can not be directly produced by
the animal's body. Accordingly, the daily requirements for each vitamin must be met through
regular dietary intake of appropriate quantities of the vitamin(s). There are two general
chemical categories of vitamins based on their solubility: water soluble vitamins (the B
vitamins and others) and fat soluble vitamins (A, D, E and K).
What is a hormone?
A hormone is a chemical messenger that is produced and secreted by specific glands and cells
within the body of animals. After secretion of the hormone, it is transported through the
bloodstream to designated target organs where the hormone by binding to its specific personal
receptor delivers its "message" to that set of cells. These cells then promptly produce
biological responses specific for that hormone.
What is vitamin D and why is it important:
Chemistry: There are two chemical forms of vitamin D, namely vitamin D2 (sometimes
referred to as ergocalciferol) and vitamin D3 (sometimes referred to a cholecalciferol). The
natural form of vitamin D for animals and man is vitamin D3; it can be produced in their
bodies from cholesterol and 7-dehydrocholesterol. An alternative vitamin D2 is commercially
prepared from ergosterol that is present in yeast.
The molecular structure of vitamin D is closely allied to that of the classical steroid hormones,
e.g. cortisol, estradiol, progesterone, aldosterone, and testosterone (3). All steroid hormones
and vitamin D3 are chemically related to the well known sterol cholesterol. Cholesterol in
animals and man is a precursor substance for all steroid hormones and as well vitamin D3.
Technically the molecule called vitamin D3 is not really a vitamin because it can be produced
by exposure of the skin (higher animals and humans) to ultraviolet light or sunlight. The skin
of many animals and man has a high concentration of the sterol cholesterol which is converted
by enzymes in the skin to the sterol 7-dehydrocholesterol. Exposure of skin (including human
skin) to sunlight for regular intervals results in the photochemical conversion of 7dehydrocholesterol into vitamin D3. This sunlight- generated vitamin D3 is a precursor of the
steroid hormone 1a,25(OH)2D3. Under these circumstances vitamin D3 is not a vitamin
because it has been produced by the body (with the assistance of sunlight). However, if the
animal or man lives in the absence of sunlight (e.g., Alaska in the winter) or exclusively
indoors, then there is indeed an absolute regular requirement for the fat soluble vitamin D,
that must be met through proper dietary intake.
Therefore for nutritional and public health reasons, vitamin D3 continues to be classified even
today in 2012 officially as a vitamin. Thus many vitamin capsules and food sources including
cows milk are supplemented with vitamin D3 to improve their nutritional value. In the 1940's
this milk supplementation process reduced the incidence rate of juvenile rickets by 85% in the
United States.
Importance: Vitamin D3 is essential for life in higher animals. Classically vitamin D3 has
been shown to be one of the most important biological regulators of calcium metabolism
through stimulating the absorption of calcium from food across the intestine and participating
in the incorporation of the absorbed calcium into the skeleton (2). These important biological
effects are only achieved as a consequence of the metabolism of vitamin D into a family of
daughter metabolites, including 1a,25(OH)2-vitamin D3 [1a,25(OH)2D3]. 1a,25(OH)2D3, is
considered to be a steroid hormone because the general mechanism by which it produces the
biological responses attributed to vitamin D is similar to those of steroid hormones (3;4).
It has become increasingly apparent since the 1980s that 1a,25(OH)2D3 also plays an
important multidisciplinary role in tissues not primarily related to mineral metabolism, e.g.
activation of the immune system, both innate and adaptive, in the pancreas where it facilitates
insulin secretion, in muscle where it improves muscle strength, and in the heart and
cardiovascular systems, where it is concerned with heart muscle function and blood pressure
regulation.,
Vitamin D Deficiency: The classic deficiency state resulting from a dietary absence of
vitamin D3 or lack of ultraviolet (sunlight) exposure is the bone disease called rickets in
children or osteomalacia in adults. The clinical features of rickets and osteomalacia depend
upon the age of onset. The classical skeletal disorder of rickets includes deformity of the
bones, especially in the knees, wrists, and ankles, as well as associated changes in the rib joint
functions, which have been termed by some as the rachitic rosary (1). A regular access to
vitamin D3 throughout life is important to facilitate the normal absorption into the body of
dietary calcium which, in turn, is essential for normal bone health and may diminish or
prevent the onset in the elderly of the bone disease osteoporosis.
Requirements for vitamin D:
Since vitamin D3 is produced in the skin after exposure of 7-dehydrocholesterol to sunlight,
the human does not have a requirement for vitamin D when sufficient sunlight is available.
Man's tendency to wear clothes, to live in cities where tall buildings block adequate sunlight
from reaching the ground, to live indoors, to use synthetic sunscreens that block ultraviolet
rays, and to live in geographical regions of the world that do not receive adequate sunlight, all
contribute to the inability of the skin to biosynthesize sufficient amounts of vitamin D3 (5).
Thus, vitamin D3 does become an important nutritional factor in the absence of sunlight. It is
known that a substantial proportion of the U.S. population is exposed to suboptimal levels of
sunlight. This is particularly true during winter months (6;7). Under these conditions, vitamin
D becomes a true vitamin which dictates that it must be supplied in the diet on a regular basis.
Since vitamin D3 can be produced by the body and since it is retained for long periods of time
by animal tissues, it has been difficult to determine with precision the minimum daily
requirements for this fat soluble vitamin. The requirement for vitamin D3 is also known to be
dependent on the age, sex, degree of exposure to the sun, season, and the amount of
pigmentation in the skin (8).
The current "adequate intake" allowance of vitamin D recommended in 2010 by the Food and
Nutrition Board of the US Institute of Medicine is 600 IU/day (15 µgrams/day) for children
and adult males and females up to age 70 (9). For adults greater than 70 years, the
recommended intake is 800 IU (20 µgrams/day).The adequate allowance for pregnancy and
lactation is set at 600 IU/day (15 µg/day). These recommendations are all summarized in a
2010 publication from the Food and Nutrition Board of the Institute of Medicine (9).
In the United States adequate amounts of vitamin D3 can readily be obtained from the diet
and/or from casual exposure to sunlight. The ultraviolet exposure can be as little as 3 X per
week exposure of the face and hands to ambient sunlight for 20 minutes (10). However, in
some parts of the world where food is not routinely fortified and sunlight is often limited
during some periods of the year, obtaining adequate amounts of vitamin D becomes more of a
problem. As a result, the incidence of rickets in these countries is higher than in the United
States.
What are the sources of vitamin D for humans?
Animal products constitute the primary source of vitamin D that occurs naturally in
unfortified foods. Salt water fish such as herring, salmon, sardines, and fish liver oils are good
sources of vitamin D3. Small quantities of vitamin D3 are also found in eggs, veal, beef,
butter, and vegetable oils while plants, fruits, and nuts are extremely poor sources of vitamin
D. In the United States, fortification of foods such as milk (both fresh and evaporated),
margarine and butter, cereals, and chocolate mixes help in meeting the adequate intake (RDA)
recommendations (11). Because only fluid milk is fortified with vitamin D, other dairy
products (cheese, yogurt, etc.) only provide the vitamin that was produced by the animal
itself.
How is vitamin D produced commercially for food supplementation>
When the critical importance to human health of a regular dietary access to vitamin D3 was
understood (in the 1930's), milk suppliers realized it would be advantageous to their
customers' health to market milk which had been supplemented with vitamin D3. Thus there
developed in the 1940's, and continues to the present, a large business of industrial production
of vitamin D3 used for the supplementation of foods for human consumption: milk (both
homogenized and evaporated), some margarine and breads. Since the 1960's vitamin D3 has
been used also for the supplementation of farm animal and poultry food.
In 1973 in the United States some 290 trillion (290 x 10-12) International Units of vitamin D3
was manufactured and sold for over 3 million dollars. This vitamin D3 is the equivalent of
approximately 8 tons.
The commercial production of vitamin D3 is completely dependent on the availability of
either 7-dehydrocholesterol or cholesterol. 7-Dehydrocholesterol can be obtained via organic
solvent extraction of animal skins (cow, pig or sheep) followed by an extensive purification.
Cholesterol typically is extracted from the lanolin of sheep wool and after thorough
purification and crystallization can be converted via a laborious chemical synthesis into 7dehydrocholesterol. It should be appreciated that once chemically pure, crystalline 7dehydrocholesterol has been obtained, it is impossible to use any chemical or biological tests
or procedures to determine the original source (sheep lanolin, pig skin, cow skin, etc.) of the
cholesterol or 7-dehydrocholesterol.
Next the crystalline 7-dehydrocholesterol is dissolved in an organic solvent and irradiated
with ultraviolet light to carry out the transformation (similar to that which occurs in human
and animal skin) to produce vitamin D3. This vitamin D3 is then purified and crystallized
further before it is formulated for use in dairy milk and animal feed supplementation. The
exact details of the chemical conversion of cholesterol to 7-dehydrocholesterol and the
method of large-scale ultraviolet light conversion into vitamin D3 and subsequent purification
are closely held topics for which there have been many patents issued (3).
Historically, the major producers of vitamin D3 used for milk and other food supplementation
were the companies F. Hoffman La Roche, Ltd (Switzerland) and BASF (Germany). Today
much of the commercially produced vitamin D2 is manufactured in China.
What is the source of vitamin D in milk?
Milk from all lactating animals, including humans, contains vitamin D3 that has been
produced photochemically from 7-dehydrocholesterol present in the skin. In cow's milk it has
been determined that the concentration of vitamin D3 in milk provided by the cow is roughly
35-70 International Units per quart as determined via biological assay (12) and approximately
50-80 International Units as determined by modern chemical mass spectrometric procedures
(13). However these are rather low levels of vitamin D3 from the perspective of providing the
600 IU per day as recommended by the Food and Nutrition Board of the Institute of Medicine
in 2010.. Accordingly, as discussed above, the business practice of supplementing cows milk
with chemically synthesized vitamin D3 was initiated. At the present time almost all milk sold
commercially in the United States has 400 IU of chemically synthesized vitamin D3 added
per quart. Any vendor of milk for human consumption containing added vitamin D3 is
required by the US Food and Drug Administration (FDA) to include a notice on the milk
carton label. Usually this label states "400 IU of added vitamin D3". However it is not
required by law to indicate either the manufacturer of the added vitamin D3 or the sources of
the cholesterol and 7-dehydrocholesterol used for its production.
It is a fact that most milk sold in the US will contain vitamin D3 with two origins. (a) That
vitamin D3 made by the cow using sunlight to irradiate 7-dehydrocholesterol present in her
skin. (b) That vitamin D3 made by a chemical process and then added to the cow milk as a
nutritional supplement. It is simply not possible to distinguish the origins of the two vitamin
D3 preparations by any biological or chemical procedure, because they are the same
molecular structure. Further, there is no legal requirement for the manufacturer of the vitamin
D3 formulated for human food supplementation to specify the animal sources of the precursor
molecules that were employed in the synthesis of the D vitamin.
If a "food product" is construed to include a chemically pure substance that is the same in all
animal species, then those individuals with strict religious reasons for avoiding food products
from a particular species have, in the instance of milk and vitamin D3, a dilemma.
Selected references:
Also the WEB sites for the Vitamin D Workshop and provides other general information
related to vitamin D.
Reference List
14. Norman,A.W. and Litwack,G.L. Hormones, Academic Press, San Diego,
CA.(1997).
15. Norman,A.W. Vitamin D: The calcium homeostatic steroid hormone., Academic
Press, New York.(1979).
16. # Bouillon,R., Okamura,W.H., and Norman,A.W. Structure-function relationships
in the vitamin D endocrine system. Endocr.Rev. 16 (1995) 200-257.
17. Norman,A.W.: Vitamin D. In Present knowledge in nutrution (PKN7). Ziegler,E.E.
and Filer,L.J., Eds., International Life Sciences Institute, Washington (1996) pp.
120-129 .
18. Holick,M.F. Environmental factors that influence the cutaneous production of
vitamin D. Am.J.Clin.Nutr. 61 Suppl. (1995) 638S-645S.
19. Webb,A.R. and Holick,M.F. The role of sunlight in the cutaneous production of
vitamin D3. Ann.Rev.Nutr. 8 (1988) 375-399.
20. Webb,A.R., Pilbeam,C., Hanafin,N., and Holick,M.F. An evaluation of the relative
contributions of exposure to sunlight and of diet to the circulating
concentrations of 25-hydroxyvitamin D in an elderly nursing home population
in Boston. Am.J.Clin.Nutr. 51(6) (1990) 1075-1081.
21. Harris,S.S. and Dawson-Hughes,B. Seasonal changes in plasma 25hydroxyvitamin D concentrations of young American black and white women.
Am.J.Clin.Nutr. 67 (1998) 1232-1236.
22. Food and Nutrition Board. Dietary reference intakes: A risk assessment model
for establishing upper intake levels for nutrients. 1998) , 1-71. Washington, D.C.,
National Academy Press, Institute of Medicine.
23. Adams,J.S., Clemens,T.L., Parrish,J.A., and Holick,M.F. Vitamin-D synthesis
and metabolism after ultraviolet irradiation of normal and vitamin-D-deficient
subjects. New Engl.J.Med. 306 (1982) 722-725.
24. Collins,E.D. and Norman,A.W.: Vitamin D In Handbook of vitamins. Machlin,L.J.,
Ed., Marcel Dekker, New York (1990) pp. 59-98 .
25. Hollis,B.W., Roos,B.A., and Lambert,P.W.: Vitamin D compounds in human and
bovine milk In Advances in nutritional research. Draper,H.H., Ed., Plenum
Press, New York (1994) pp. 59-75 .
26. Adachi,A. and Kobayashi,T. Identification of vitamin D3 and 7dehydrocholesterol in cow's milk by gas chromatography-mass spectrometry
and their quantitation by high-performance liquid chromatography.
J.Nutr.Sci.Vitaminol. 25 (1979) 67-78.