Vitamins (Lipid soluble)

Metabolic activity

Vitamin A (Retinol, retinal and retinoic acid)

Oxidation-reduction activity, visual cycle, necessary for normal synthesis of chondrotin sulphate.

Vitamin D ( D­₂– ergocalciferol, D₃– cholecalciferol)

Absorption of calcium from intestine

Necessary for calcification of bone matrix.

Vitamin E (α- tocopherol)

Inhibits autooxidation of unsaturated fatty acids.

Vitamin K (Phylloquinine)

Necessary for hepatic synthesis of proconvertin.

Vitamins (Water soluble)

Metabolic activity

Thiamine (B₁)

Decarboxylation of pyruvic acid.

Transketolase reaction of hexose-monophosphate shunt.

Riboflavin (B₂)

Biosynthesis of flavin nucleotide (FAD, FMN)

Used in oxidation-reduction reactions.

Nicotinamide

Component of pyrimidine nucleotides (DPN and TPN)

Necessary for biological oxidation-reduction

Pyridoxine/ pyridoxal/pyridoxamine (B₆)

Amino acid metabolism

Active transport across cell membrane

Pantothenic acid

Component of acetyl coenzyme A

Acyl carrier protein

Folic acid

Cofactor in active-methyl or one-carbon metabolism

Choline

Necessary for synthesis of lecithin

Lipid metabolism

Biotin

Necessary for incorporation of CO₂ into organic compounds

Cyanocobalamin (B₁₂)

Glutamic acid metabolism

Certain alcohol and synthesis of nucleic acid

Vitamin C (ascorbic acid)

Oxidation-reduction reactions