VITAMINS
Three key characteristics of a compound as a vitamin
1. It must be a vital organic substance that is not energy-producing which is usually
necessary in only very small quantities
2. It cannot be manufactured by the body
3. Its absence or underutilization causes a specific deficiency syndrome
Other terms for vitamins: accessory food factor, advitant, biocatalyst, catalin, ergin, exogenous
hormones, nutrillite, vitamer, vitazyme
CLASSIFICATION OF VITAMINS
• Vitamins are usually grouped according to their solubility in either fat or water
A. Fat Soluble
o Vitamins A, D, E, and K
o Can be stored in the body, hence deficiency tends to develop slowly
o Functions are generally related to structural activities
General Properties of Fat-Soluble Vitamins
- Soluble in fat or fat solvent
- Excess is stored in the body
- Not absolutely needed in the diet
- These vitamins have precursors
- Fairly stable to heat as in cooking
- Absorbed in the intestines together with lipids
- Requires bile for absorption
B. Water Soluble
o Vitamins C and the B-complex family
o Absorbed and transported in aqueous medium
o Not stored to a large extent
o The B vitamins function mainly as coenzyme factors
o Vitamin C is a structural component
General Properties of Water-Soluble Vitamins
- Soluble in water
- Minimal storage of dietary excesses
- Excreted in the urine
- Deficiency symptoms often develop rapidly
- Must be supplied every day in the diet
- Generally, they do not have precursors
-
ANTIVITAMINS
- Certain compounds are structurally related to vitamins but do not have vitamin activity.
These compounds which interfere with the normal functioning of vitamins by:
1. Competitive inhibition
2. Inactivation
3. Destruction
Three key characteristics of a compound as a vitamin
1. It must be a vital organic substance that is not energy-producing which is usually
necessary in only very small quantities
2. It cannot be manufactured by the body
3. Its absence or underutilization causes a specific deficiency syndrome
Other terms for vitamins: accessory food factor, advitant, biocatalyst, catalin, ergin, exogenous
hormones, nutrillite, vitamer, vitazyme
CLASSIFICATION OF VITAMINS
• Vitamins are usually grouped according to their solubility in either fat or water
A. Fat Soluble
o Vitamins A, D, E, and K
o Can be stored in the body, hence deficiency tends to develop slowly
o Functions are generally related to structural activities
General Properties of Fat-Soluble Vitamins
- Soluble in fat or fat solvent
- Excess is stored in the body
- Not absolutely needed in the diet
- These vitamins have precursors
- Fairly stable to heat as in cooking
- Absorbed in the intestines together with lipids
- Requires bile for absorption
B. Water Soluble
o Vitamins C and the B-complex family
o Absorbed and transported in aqueous medium
o Not stored to a large extent
o The B vitamins function mainly as coenzyme factors
o Vitamin C is a structural component
General Properties of Water-Soluble Vitamins
- Soluble in water
- Minimal storage of dietary excesses
- Excreted in the urine
- Deficiency symptoms often develop rapidly
- Must be supplied every day in the diet
- Generally, they do not have precursors
-
ANTIVITAMINS
- Certain compounds are structurally related to vitamins but do not have vitamin activity.
These compounds which interfere with the normal functioning of vitamins by:
1. Competitive inhibition
2. Inactivation
3. Destruction
