Vitamin A is converted to retinol in the eye and is also responsible for the stability of cellular membranes.

Vitamin D₃ plays a major role in the regulation of calcium and phosphate plasma concentrations.

Vitamin E functions as an antioxidant and free radical agent particularly for the unsaturated fatty acids in the phospholipids of cell membranes.

Vitamin B₁ acts as a co-enzyme in the breakdown of glucose and glycogen.

Vitamin B₂ Sodium Phosphate is phosphorylated to form the co-enzymes Riboflavin-5-phosphate and Flavin Adenine Dinucleotide (FAD) which act as hydrogen recipients and donors.

Vitamin B₆ is converted to pyridoxal phosphate which functions as a co-enzyme with the transaminases and decarboxylases in the metabolism of proteins and amino acids.

Nicotinamide is converted to the essential co-enzymes. Nicotinamide Adenine Dinucleotide (NAD) and Nicotinamide Adenine Dinucleotide Phosphate (NADP).

Pantothenol or pantothenic acid is converted to Co-ensyme A which has a key role in the metabolism of carbohydrates and amino acids and in the synthesis of fatty acids, steroids and acetyl co-enzyme A.

Vitamin B₁₂ is required for the synthesis of nucleic acid components, synthesis of red blood cells and the metabolism of propionate.

Vitamins are essential for the proper operation of numerous physiologica functions.