VITAMINS
Definition and Classification
Non-caloric organic nutrients
 Needed in very small amounts
 Facilitators – help body processes
proceed; digestion, absorption,
metabolism, growth etc.
 Some appear in food as precursors or
provitamins

Definition and Classification

2 classes

Fat soluble:

Water soluble:
Definition and Classification

Fat soluble vitamins
Found in the fats and oils of food.
 Absorbed into the lymph and carried in
blood with protein transporters =
chylomicrons.
 *Stored in liver and body fat and can
become toxic if large amounts are
consumed.

Definition and Classification

Water soluble vitamins
Found in vegetables, fruit and grains, meat.
 Absorbed directly into the blood stream
 Not stored in the body and toxicity is rare.
Alcohol can increase elimination, smoking,
etc. cause decreased absorption.

Fat Soluble Vitamins

Vitamin A


3 forms: retinol (stored in liver), retinal, retinoic acid
Roles in body:





Regulation of gene expression
Part of the visual pigment rhodopsin, maintains clarity of
cornea (yes eating carrots is good for your eyesight)
Required for cell growth and division - epithelial cells,
bones and teeth
Promotes development of immune cells, especially
“Natural Killer Cells”
Antioxidant
Fat Soluble Vitamins

Vitamin A

Deficiencies cause:
Night blindness, xerophthalmia (keratin deposits
in cornea), muscular degeneration.
 Skin and mucous membrane dryness and
infection, keratin deposits.
 Anemia
 Developmental defects – bones, teeth, immune
system, vision

Fat Soluble Vitamins

Vitamin A

Toxicities (RetinA/Accutaine, single large
doses of supplements, eating excessive
amounts of liver) cause:
Fragile RBCs, hemorrhage
 Bone pain, fractures
 Abdominal pain and diarrhea
 Blurred vision
 Dry skin, hair loss
 Liver enlargement

Fat Soluble Vitamins

Vitamin A

DRI: 700(women)-900(men)
micrograms/day, UL 3000 micrograms/day
Snapshot 7-1, p, 219
Fat Soluble Vitamins

Vitamin D – precursor is cholesterol,
converted by UV from sunlight exposure,
therefore is a “non-essential” vitamin.

Roles:
Increases calcium absorption in bone, intestines,
kidney. Promotes bone growth and
maintenance.
 Stimulates maturation of cells – heart, brain,
immune system, etc.

Fat Soluble Vitamins

Vitamin D
Deficiencies: rickets (children),
osteomalacia (adults). What are some of
the causes of deficiencies?
 Toxicities (5X DRI)

Loss of calcium from bone and deposition in soft
tissues.
 Loss of appetite, nausea and vomiting,
psychological depression.

Bowed legs – Characteristic of
rickets
Beaded ribs –
Characteristic
of rickets
Fig. 7-5b, p. 222
Fat Soluble Vitamins

Vitamin D
DRI – 5 micrograms/day for ages 19-50, 10
for ages 51-70, 15 for ages >70.
 Sources, see snapshot 7.2

Snapshot 7-2, p, 223
Fat Soluble Vitamins

Vitamin E – tocopherol, *alpha-, beta -,
gamma-, and delta
Roles:
Antioxidant (protects polyunsaturated fats)
 Prevention of damage to lungs, RBCs, WBCs
(immunity), heart
 Necessary for normal nerve development

Fat Soluble Vitamins

Vitamin E

Deficiencies (decreased absorption of fatsliver disease, low fat diets)
Premature babies – fragile RBCs (hemolysis)
 Loss of muscle coordination, vision, immune
functions


Toxicities (more than 1000 milligrams/day)

Increases the effects of anticoagulants
(Coumadin, Warfarin)
Fat Soluble Vitamins

Vitamin E
DRI 15 milligrams/day (alpha-tocopherol)
 Sources, see snapshot 7.3

Snapshot 7-3, p, 226
Fat Soluble Vitamins

Vitamin K – produced by bacteria in large
intestine

Roles




Promotes synthesis of blood clotting proteins (**Interferes
with Coumadin)
Bone formation
Deficiencies are rare but seen in infants, after
prolonged antibiotic therapy, and in patients with
decreased bile production.
Toxicities (>1000 mg/day): rupture of RBCs and
jaundice
Fat Soluble Vitamins

Vitamin K
DRI: 90(women) – 120(men)
micrograms/day
 Sources, see snapshot 7.4

Snapshot 7-4, p, 228
Water Soluble Vitamins

8 B vitamins – Tender Romance Never Fails with 6 to 12
Beautiful Pearls (Thiamin, Riboflavin, Niacin,
Folate, B6, B12, Biotin, and Pantothenic
acid)
Aid in metabolism of and energy release
from carbohydrates, lipids, amino acids.
 Mode of action – coenzymes or parts of
coenzymes that are necessary for the
proper activity of enzymes, fig 7.9

Compounds
Without the coenzyme, compounds A
and B don’t respond to the enzyme.
A
B
Active site
Enzyme
With the coenzyme in place, compounds
A and B are attracted to the active site
on the enzyme, and they react.
A
B
Vitamin
Coenzyme
Enzyme
The reaction is completed with the
formation of a new product. In this case,
the product is AB.
The product AB is released.
A B
Enzyme
A B
New product
Enzyme
Fig. 7-9a, p. 233
Brain and
other tissues
metabolize
carbohydrates.
Muscles and
other tissues
metabolize
protein.
Liver and other
tissues
metabolize fat.
Bone tissues
make new
blood cells.
Digestive
tract
lining
replaces
its cells.
Fig. 7-10, p. 234
Water Soluble Vitamins

Thiamin and Riboflavin


Roles – energy metabolism in cells, part of nerve
cell membranes.
Deficiencies




Beri beri, edema &/or muscle weakness
Alcohol abuse – Wernicke-Korsakoff syndrome
DRI thiamin:1.1(women) – 1.2(men) mg/day;
riboflavin 1.1(women) – 1.3(men) mg/day
Sources: All food groups except fats and oils
Snapshot 7-6, p, 236
Snapshot 7-7, p, 237
Water Soluble Vitamins

Niacin – can be produced from the
amino acid tryptophan.
Roles: energy metabolism
 Deficiencies: Pellagra – dermatitis,
diarrhea, dementia, death
 Toxicities: prevents blood clotting, causes
liver damage, enhances action of Coumadin

Water Soluble Vitamins

Niacin

DRI 14(women) -16(men) mg/day
Meats
 Some vegetables and grains

Snapshot 7-8, p, 238
Water Soluble Vitamins

Folate
Role: required for synthesis of DNA
 Deficiencies (drug interactions, smoking)

Anemia
 Decreased immunity
 Decreased digestive and cardiovascular function
 Colon and cervical cancers
 *Neural tube defects, & other birth defects

Water Soluble Vitamins

Folate
Toxicities (>1000 mg/day): rare, interferes
with anticancer drugs.
 DRI 400 milligrams/day
 Sources, snapshot 7.8

Snapshot 7-9, p, 240
Water Soluble Vitamins

Vitamin B12 (requires intrinsic factor for
absorption)
Roles: works with folate, part of insulating
sheath around nerves.
 Deficiencies:

Pernicious anemia
 Paralysis
 Nerve damage in fetus

Water Soluble Vitamins

Vitamin B12
DRI 2.3 micrograms/day
 Sources, see snapshot 7.9


Meat and dairy
Snapshot 7-10, p, 242
Water Soluble Vitamins

Vitamin B6

Roles:

Conversion of amino acids to other amino acids

Ex.: Tryptophan to niacin
Synthesis of hemoglobin and neurotransmitters
 Release of glucose from glycogen
 Immune function
 Promotes steroid hormone activity
 Development of nervous system

Water Soluble Vitamins

Vitamin B6

Deficiencies
Anemia
 Dermatitis
 Muscle weakness
 Behavioral problems
 Heart disease


Toxicities (>100 mg/day) – muscle
weakness, nerve damage
Water Soluble Vitamins

Vitamin B6
DRI 1.3 milligrams/day
 Sources, see snapshot 7.10

Meat and dairy
 Vegetables and fruits

Snapshot 7-11, p, 243
Water Soluble Vitamins

Biotin and Pantothenic acid

Roles:
Metabolism of carbohydrates, fats and proteins
 Synthesis of lipids, neurotransmitters, steroid
hormones, hemoglobin.

Water Soluble Vitamins

Vitamin C, ascorbic acid – history of
controversy

Roles:
Connective tissue development, collagen
 Antioxidant
 Promotes iron absorption, immunity
 Protects vitamin E

Water Soluble Vitamins

Vitamin C






Deficiency – Scurvy (skin and mucous membrane
damage), anemia.
Toxicity (> 2grams/day) – pro-oxidant, activates
oxidizing agents.
DRI – 75(w) – (90(m) milligrams/day. Increased for
smokers.
Sources, see snapshot 7.11
Notes: can interfere with diagnostic tests for
diabetes, and blood clotting
Prevents colds
Snapshot 7-5, p, 232