Nutrition Facts

What is the importance of niacin?

Niacin or nicotinic acid belongs to B-complex group of vitamins and is essential vitamin for maintaining optimal health. Niacin is required for metabolism of the major constituents of food namely proteins, fats and carbohydrates. Niacin is also essential for smooth functioning of nervous system, GIT (gastrointestinal system) and also for maintaining normal texture of skin or maintaining skin health.

In which way niacin differs from other B-complex group of vitamins?

Niacin differs from other B-complex group of vitamins in that it is produced from an essential amino acid “tryptophan” which serves as a precursor of niacin (in other words a single chemical step of tryptophan produces niacin). Another way niacin differ from other B-complex group of vitamins is that niacin is not excreted in the urine as such (as niacin), unlike other B-complex group of vitamins which are excreted in urine without undergoing any change. Niacin is excreted in the urine as in two of its major metabolites namely N-methyl-nicotinamide and N-methyl-pyridone.

What are the food sources of niacin?

As mentioned earlier, niacin is produced from essential amino acid tryptophan, so any food source which is rich in tryptophan is a good source of niacin. Food sources which are rich in niacin are liver, meat, kidney, fish, poultry, and legumes, peanuts etc. many of the foods are poor in niacin but are rich in tryptophan and can act as good source of niacin e.g. milk, as milk proteins are rich in niacin. Many cereals and grains (e.g. maize) have niacin in “bound form” and niacin is not available for use and can not act as source despite having good quantity of niacin in bound form.

Niacin is formed from tryptophan with just single chemical step. To produce 1 mg of niacin, approximately 60 mgs of tryptophan is required.

The daily recommended requirement of riboflavin is 0.6 mg per 1000 Kcal of energy intake. If a person is consuming 3000 Kcal of energy per day he/she will require approximately 1.8 mg of riboflavin per day. There is no body store of riboflavin and it has to be consumed daily to prevent deficiency disorders of riboflavin. Vitamin-health is incomplete without recommended intake of riboflavin every day.

Deficiency of riboflavin:

The deficiency of riboflavin is known as “ariboflavinosis”. Deficiency of riboflavin is common in many areas of the world. It is more common, especially in the developing countries where rice is the staple food. The reason is, riboflavin is destroyed during cooking of rice as riboflavin is a water soluble vitamin. Ariboflavinosis is sometimes used as an index of malnutrition (state of nutrition) during clinical survey of malnutrition.

The most common symptom associated with riboflavin deficiency is angular stomatitis (inflammation of angle of the mouth) and this occurs frequently among malnourished children (so used as index of malnutrition in malnutrition surveys). Other clinical signs of riboflavin deficiency are glossitis, nasolabial deformity etc. But these are not specific signs of riboflavin deficiency, unlike angular stomatitis.

In many under developed countries the sub-clinical deficiency of riboflavin (hypo riboflavinosis) is present in as many as 80% of the children among lower income groups. Sub clinical riboflavin deficiency is determined by a test known as “erythrocyte glutathione reductase activation test”. Hyporiboflavinosis do not incapacitate the child even if it is very severe, but it can cause many problems of function, especially neurological functions like impaired neuromotor function, impaired wound healing and increased susceptibility to develop cataract (possibly).

Deficiency of riboflavin generally occurs along with deficiency of other B-complex group of vitamins and presents as a part of multiple vitamin deficiency syndrome. But fortunately deficiency of riboflavin is becoming uncommon even in developing countries due to diversification of diet.

Riboflavin is the second among B complex group of vitamins to be identified and so named as vitamin B₂. The main use of riboflavin is in cellular oxidation. Riboflavin also plays a very important role in maintaining the structural integrity of the mucosal layers of the body. In the energy metabolism Riboflavin plays as a co-factor with many enzymes and is essential in maintaining vitamin-health of individuals.

Richest food sources of Riboflavin:

Among plant and animal foods the richest sources of Riboflavin are green leafy vegetables, eggs, liver, milk and kidneys.

Plant sources of Riboflavin:

Riboflavin is widely distributed in the plant kingdom. But some of the plant foods are particularly rich in Riboflavin like green leafy vegetables. Other plant sources of Riboflavin are different cereals (whole as well as milled, unlike thiamin which is present mainly in whole cereals and very less in milled cereals). Pulses are not very rich source, but it can be important source if consumed in larger quantity, as is seen in countries like India and other south Asian countries. The Riboflavin contents of pulses can be increased significantly by germination. For germination pulses (with husk) are soaked in water for approximately 24 hours and cooked after that. Excess cooking can cause loss of riboflavin in the foods.

Animal (meat) sources of Riboflavin:

Many animal foods are rich in Riboflavin. Examples of rich animal sources of Riboflavin are all type of meat, eggs (especially hens egg), liver (especially sheep liver), milk (especially cow’s milk) etc.