Nutrition Facts

Deficiency of niacin causes pellagra. Pellagra was once a widespread disease, especially in certain areas. It was highly prevalent in certain poor regions of the world due to malnutrition. At present pellagra has declined significantly throughout the world, but pellagra is still prevalent in some parts of the world like Western parts of Asia and Southern parts of Africa, as in these regions poor people sustain only on maize and little else and in the maize niacin is present in the “bound” form and not available for use by human body. Human body can not free the bound form of niacin from maize.

Pellagra is traditionally a disease of maize eating regions, where maize is the staple diet and it occurs among poor people as they eat mainly maize and very little else and do not get enough niacin from other food sources (as they consume very little of other foods). That is why pellagra is still prevalent in many maize eating areas of the world where poverty is still predominant.

Although pellagra is predominantly a disease of maize eating regions in some parts of India (like in some segment of Telangana area of Andhra Pradesh State of India) pellagra is reported. In a study it was found that the pellagra in that area is due to consumption of Sorghum vulgare (locally known as jowar) as staple diet and traditionally people are pure vegetarians in the area and do not consume milk or foods of other animal origin. In the study it was found that there is excess of an amino acid leucin in Sorghum vulgare or jowar, which cause imbalance in amino acids and excess leucin interfere with conversion of tryptophan to niacin, thereby causing deficiency of niacin and consequently pellagra results.

What are the symptoms of pellagra?

Pellagra is characterized by Diarrhea, Dermatitis and Dementia (loss of memory or unable to remember), classically known as three D’s. Other symptoms of pellagra includes glossitis (inflammation of the tongue and the tongue becomes enlarged), stomatitis (inflammation of the lips which also becomes enlarged) etc. The dermatitis of pellagra occurs only in those areas or parts of the skin which is exposed to sunlight and generally is symmetrical. The common areas where dermatitis occurs in pellagra are face, hands, legs and the back. Along with dementia, other mental changes like irritability, delirium, depression etc. can occur in pellagra.

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.