Effect of Carbohydrates, Fat and Proteins on Vitamin Requirements

•Dietary carbohydrates, fats and proteins influence the requirements of some vitamins. Some examples:

•Thiamin: Carbohydrates present in the diet require thiamin for their metabolism, as thiamin pyrophosphate (TPP) is a coenzyme for the oxidative decarboxylation of pyruvic acid, the main breakdown product of carbohydrate.

•Thiamin is not required for the oxidation of fat. Hence, the presence of excess fat in diet decreases, while the presence of excess carbohydrates increases thiamine requirements.

•Riboflavin: The riboflavin requirements have been found to be proportional to the protein content of the diet in experimental animals.

•Niacin: Tryptophan present in proteins is converted to niacin in the body. A part of the niacin requirements is met by the above process. Hence, tryptophan present in proteins can serve as a source of niacin.

•Pyridoxine (Vitamin B6): The requirements of vitamin B6 are influenced by both the quantity and quality of dietary proteins and fats.

•The pyridoxine requirements are directly proportional to the protein content of the diet. Supplementation of dietary proteins increases pyridoxine requirements.

•On the other hand, addition of essential fatty acids to a low pyridoxine diet offers protection against the development of the deficiency sign of pyridoxine deficiency.

•Vitamin A, E and K: Vitamin K deficiency diet develop signs of vitamin K deficiency in rats when vitamin A intake is increased. Administration of vitamin E helps to increase the storage of vitamin A in liver.