VITAMINS
There are 13 vitamins – 2 groups – water soluble
- fat soluble
Water-soluble vitamins (B-complex and C)
 Turnover is rapid - ~ 48 hours
 Excessive intake generally excreted (tend not to be
toxic)
 Function as coenzymes i.e. they work with one or more
enzymes that allow a chemical reaction to occur
 RDA(Recommended Dietary Allowance) depends on
1.
Age group, sex
2.
Pregnancy, lactation
3.
Bioavailability
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4.
Stability of vitamin i.e. some vitamins are
unstable when exposed to heat, light and even air.
Deficiencies of Water-Soluble Vitamins
Deficiency problems occur over a period of time when an
individual goes from ample supply of a vitamin to a vitamindeficient diet:
 Sufficient supply of vitamin in body tissue
 Tissue levels of vitamin decline steadily
 After about 3 – 4 weeks
Enzyme activity decreases
 After 6 – 8 weeks
Outward signs of deficiency appear (skin, tongue
Lesions, diarrhea, muscle fatigue)
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THE B COMPLEX VITAMINS
Most of the B vitamins are involved in the breakdown
of carbohydrates, fats and protein for fuel (energy
releasers).
1. Vitamin B1 – Thiamin
 Helps turn carbohydrates into energy
 Needed for muscle co-ordination and a healthy
nervous system
 Deficiency  Beriberi (muscle fatigue, balance, heart disease, death)
2. Vitamin B2 – Riboflavin
 Helps body release energy from carbohydrates,
fat and protein
 Deficiency  general fatigue,
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3. Vitamin B3 – Niacin
 Helps body release energy from carbohydrates,
fat and protein
 Needed for healthy nervous system and mucous
membranes
 Deficiency  Pellagra
(dermatitis, diarrhea ,dementia ------ death)
4. Vitamin B6 – Pyridoxine
 Helps body use carbohydrates and protein
 Needed for healthy nervous system
 Helps body make non-essential amino acids, which
then make body cells
 Deficiency  muscle fatigue,diarrhea, anemia
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5. Vitamin B12 and Folate
These two vitamins work together and their roles are
similar:
 Help build red blood cells
 Important role in DNA, RNA replication
 Help body use carbohydrates, fat, an protein
 Important for healthy nervous system
 Deficiency – Anemia characterized by large,
immature blood cells; B12 deficiency may also
result in damaged nervous system; folate
deficiency may lead to serious birth defects.
 **B12 different from other water-soluble vitamins
in that it can be stored in liver for up to 1 year;
also B12 can ONLY be obtained from animals.
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5. Vitamin C (ascorbic acid)
 Important for production of the protein collagen (a
structural glue-like protein that makes up 25% of
total protein)
 Antioxidant –prevents oxidation of poly fats
 Aids in iron absorption
 Helps body heal wounds and resist infection
 Deficiency  Scurvy, characterized by:
o Bleeding gums, loose teeth
o Painful joints, fragile bones
o Haemhorrages under the skin
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FAT-SOLUBLE VITAMINS
 Found in fatty part of body (cells and tissues)
 Turnover very slow – months therefore can take years
before deficiency symptoms show up
 Excesses stored in body, therefore can be toxic
Vitamin A
 Low-level light vision
 Maintenance of epithelial (covering tissue) cells (SKIN)
 Growth of new bones
 Antioxidant
 Deficiency – infections, blindness, stunted growth
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Vitamin D
 Regulates calcium absorption and mineralization of bones
and teeth
 Regulates blood levels of calcium
 Deficiency  Rickets (soft bones)
Vitamin E
 Antioxidant
 Deficiency  hemolytic anemia (rare)
Vitamin K
 Blood clot formation
 Involved in mineralization of bone
 Deficiency – rare because intestinal bacteria make some
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