Vitamin D Dilemmas
Recent research by Thomas Littlejohn in “Neurology- September 2 2014” have strongly
confirmed that low Vitamin D levels are associated with an increased risk of dementia and
Alzheimers Disease, adding more fuel to the debate about the problems of low Vitamin D.
It
was thought that this provided a crucial role for vitamin D in neuronal function.
The authors propose that Vitamin D and its metabolites mediate the synthesis of various
neurotransmitters including acetylcholine, catecholamines, serotonin, and dopamine. Vitamin
D also helps maintain neurite outgrowth and promote synaptic plasticity, influences
neurotransmitter synthesis, protects against oxidative stress and mitochondrial dysfunction,
reduces the proinflammatory response, and may regulate ageing.
Search or recent literature is very confusing, with basically little evidence to substantiate
supplementation except in people with very low levels, with now the confusion about cognitive
decline. Or is it?
In many of the areas we have been working in, eg FMS, migraine, IBS, low Vitamin D levels
are the norm, and given this is the Gold Coast, this is a surprising finding.
Elevated levels of
Uric acid also turn up in this group, and in many, elevated homocysteine, which is thought to
be proinflammatory and associated with a higher vascular risk (over 9 mmmol/l, not the
quoted 15 mmol/l which is an average, not normal).
It seems likely to me, and worthy of
some decent research, that it is the problem in the methylation pathway with its consequent
increased oxidative stress that may be at the real bottom of the increased dementia, and the
low Vitamin D simply just another thing we find in these diseases.
At this stage though, I
would recommend Vitamin D supplementation if you are low.
Much has been made about supplementation for a wide range of problems. I have
summarized a small sample of recent publications reviewed through Journal Watch from the
New England Journal of Medicine.
Vitamin D Supplementation Does Little to Improve Asthma Control
David J. Amrol, MD reviewing Castro M et al. JAMA 2014 May 28.
No need to check vitamin D levels in patients with uncontrolled asthma.
Vitamin D Blood Levels and Supplementation and Cause-Specific Death
Paul S. Mueller, MD, MPH, FACP reviewing Chowdhury R et al. BMJ 2014 Apr 1.
Vitamin D3 seems like the better choice for supplementation.
Alopecia Areata and Hidradenitis Suppurativa: The Vitamin D Connection
Craig A. Elmets, MD reviewing Aksu Cerman A et al. Br J Dermatol 2014 Mar 21. Kelly G et
al. Br J Dermatol 2014 Mar 5.
Patients with certain autoimmune disorders of the skin should be screened for vitamin D
deficiency.
The Evidence on Photoprotection and Vitamin D
Craig A. Elmets, MD reviewing Kannan S and Lim HW. Photodermatol Photoimmunol
Photomed 2014 Jan 9.
Less protection or more supplementation?
Careful evaluation of vitamin D status, especially in those at high risk or who avoid the sun, is
necessary to prevent the orthopedic consequences of vitamin D deficiency. Most studies
showed that sunscreens used normally do not have a major effect on vitamin D production.
Normalization of vitamin D status is difficult, if not impossible, to achieve by increasing sun
exposure or limiting sunscreen use, especially in darkly pigmented people who live farther
from the equator or in heavily polluted cities and in most people during the winter months.
Thus, recommending that patients spend a few minutes in the sun or limit sunscreen use is
unlikely to significantly raise vitamin D levels. Supplements are a much better way to achieve
vitamin D sufficiency.
Another Benefit of High Vitamin D Levels: Lower risk for diverticulitis
Douglas K. Rex, MD reviewing Maguire LH et al. Clin Gastroenterol Hepatol 2013 Dec.
A high level of vitamin D was protective against diverticulitis in patients with uncomplicated
diverticulosis.
Vitamin D Supplements Don't Prevent Respiratory Infections
Abigail Zuger, MD reviewing Rees JR et al. Clin Infect Dis 2013 Nov 15.
Occurrence and duration of colds and flu-like illness were unaffected by oral supplementation.
When It Comes to Bone, Vitamin D Supplementation Falls Short
Bruce Soloway, MD reviewing Reid IR et al. Lancet 2013 Oct 11.
In a large meta-analysis, vitamin D supplementation generally did not increase bone-mineral
density. In general, this study showed no significant increase in bone-mineral density with
vitamin D supplementation. Such a result is consistent with the understanding that vitamin D
acts primarily to increase gut absorption of calcium (not directly on bone metabolism), and
these results support the Institute of Medicine's conclusion that adults with baseline 25hydroxyvitamin D levels >20 ng/mL do not require supplementation. http://www.jwatch.org/na32572/2013/10/22/when-it-comes-bone-vitamin-d-supplementationfalls-short#sthash.Zikrso9I.dpuf
Randomized Controlled Trial of Various Doses of Supplemental Vitamin D in Infancy
Cornelius W. Van Niel, MD reviewing Gallo S et al. JAMA 2013 May 1. Abrams
SA. JAMA 2013 May 1.
For now, 400 IU still seems to be the best daily dose.
Does Vitamin D in Pregnancy Affect Maternal and Neonatal Outcomes?
Diane J. Angelini, EdD, CNM, FACNM, FAAN, NEA-BC reviewing Aghajafari F et
al. BMJ 2013 Mar 26. Lawlor DA et al.Lancet 2013 Mar 19.
Vitamin D insufficiency during pregnancy was associated with maternal and neonatal
morbidities, but did not affect bone density in children.
Although observational data suggest associations between vitamin D deficiency during
pregnancy and adverse outcomes, both for women and their offspring, the need for vitamin D
during pregnancy remains controversial. Canadian investigators conducted a meta-analysis
of 31 studies assessing the effects of maternal serum vitamin D on maternal and neonatal
outcomes. Another study concerned the effects of maternal vitamin D on bone density in
offspring.
The meta-analysis showed that pregnant women with vitamin D insufficiency (<75 nmol/L)
were at significantly elevated risk for preeclampsia and gestational diabetes. Analysis limited
to studies that reported birth variables showed a significant association between maternal
vitamin D insufficiency (defined in these studies as <37.5 nmol/L) and small-for-gestationalage infants. Low birth weight, but not birth length or head circumference, was also associated
with low maternal vitamin D. Findings in the second study (a prospective, population-based
study of 3960 mother-offspring pairs in southwest England) showed no association between
the mothers' vitamin D levels during any trimester and bone mineral density in their children
(mean age, 10 years).
- See more at: http://www.jwatch.org/wh201304250000006/2013/04/25/does-vitamin-dpregnancy-affect-maternal-and#sthash.eZH9kel3.dpuf
Correcting Low Vitamin D Levels in Obese Adolescents Improves Insulin Sensitivity
Alain Joffe, MD, MPH, FAAP reviewing Belenchia AM et al. Am J Clin Nutr 2013 Feb 13.
Adolescents who took 4000 IU of vitamin D3 daily had lower fasting insulin levels and insulin
resistance than controls.
The Effect of Milk Intake on Vitamin D and Iron Levels in Children
Mary Wu Chang, MD reviewing Maguire JL et al. Pediatrics 2013 Jan.
Consuming 2 cups of milk per day is sufficient to maintain healthy vitamin D levels without
depleting iron levels for most children at northern latitudes.
No Benefit of Vitamin D Supplementation for Knee Osteoarthritis
Thomas L. Schwenk, MD reviewing McAlindon T et al. JAMA 2013 Jan 9.
A 2-year study might have been too short, but results still are discouraging.
Short-Term Correction of Vitamin D Deficiency in Healthy Young Women
Allan S. Brett, MD reviewing Goswami R et al. J Clin Endocrinol Metab 2012 Dec.
Supplementation raised 25-hydroxyvitamin D levels substantially, but with no physical
benefits.
Vitamin D's Effect on Calcium Absorption
Allan S. Brett, MD reviewing Gallagher JC et al. J Clin Endocrinol Metab 2012 Oct.
Supplemental vitamin D enhanced calcium absorption very little among women with mild
vitamin D insufficiency.
Do Vitamin D Supplements Improve Cardiovascular Risk Factors?
Allan S. Brett, MD reviewing Wood AD et al. J Clin Endocrinol Metab 2012 Oct.
Supplements did not improve lipid levels, blood pressure, or C-reactive protein levels.
A Link Between Vitamin D and Vitiligo
Craig A. Elmets, MD reviewing Li K et al. Br J Dermatol 2012 Oct.
These findings may explain why treatments are effective in some, but not all, vitiligo patients.
Vitamin D Does Not Prevent Upper Respiratory Tract Infections
Thomas L. Schwenk, MD reviewing Murdoch DR et al. JAMA 2012 Oct 3. Linder
JA. JAMA 2012 Oct 3.
No benefit of supplementation was noted, either in incidence or severity of URTIs.
Vitamin D Supplementation Does Not Reduce Depression Risk in Older Women
Peter Roy-Byrne, MD reviewing Bertone-Johnson ER et al. Am J Epidemiol 2012 Jul 1.
Vitamin D and Calcium Supplementation in Older Adults
Allan S. Brett, MD reviewing Avenell A et al. J Clin Endocrinol Metab 2012 Feb.
A randomized trial found no effect on cancer or vascular mortality.
No Link Between Vitamin D Levels and Risk for COPD Exacerbations
Jamaluddin Moloo, MD, MPH reviewing Kunisaki KM et al. Am J Respir Crit Care Med 2012
Feb 1. Lehouck A et al. Ann Intern Med 2012 Jan 17.
Two studies were consistent in showing a lack of association.
Vitamin D and Calcium Supplements: What Do the Data Show? Who Should Be
Treated?
Craig A. Elmets, MD reviewing Chung M et al. Ann Intern Med 2011 Dec 20.
Vitamin D and calcium supplementation may lower fracture risk in some individuals, but data
regarding its effects on cancer are inconclusive.
Which Vitamin D Supplement Boosts Levels More — D2 or D3?
Allan S. Brett, MD reviewing Binkley N et al. J Clin Endocrinol Metab 2011 Apr. Heaney RP et
al. J Clin Endocrinol Metab2011 Mar.
D3 (cholecalciferol) has the edge.
New Institute of Medicine Recommendations on Vitamin D
Craig A. Elmets, MD reviewing Ross AC et al. J Clin Endocrinol Metab 2010 Nov 29.
Evidence is lacking for extraskeletal health benefits of vitamin D; most people in the U.S. and
Canada have adequate serum 25-hydroxyvitamin D levels.
Health Effects of Vitamin D: The “D”-bate Goes On
Craig A. Elmets, MD reviewing Llewellyn DJ et al. Arch Intern Med 2010 Jul 12. Grey A et
al. Arch Intern Med 2010 Jul 12.
Does vitamin D deficiency itself underlie the association with cognitive decline (and other
conditions), or does it reflect an unhealthy lifestyle?
Vitamin D Concentration and Risk for Colorectal Cancer
Paul S. Mueller, MD, MPH, FACP reviewing Jenab M et al. BMJ 2010 Jan 21.
Risk was lower when serum concentration was higher.
References:
Mittlejohns, Thomas., Henley, William., Lang, Ian et al, Vitamin D and the Risk of Dementia
and Alzheimers Disease: Neurology,
http://www.neurology.org/content/early/2014/08/06/WNL.0000000000000755.full.ht
ml
http://www.jwatch.org/