n of amino acids from the intestine and kidney (Carson-DeWitt 2004).
Niacin is part of the B vitamins or the vitamin B complex, a group of water-soluble vitamins. Niacin is found in foods such as yeast, liver, meat, fish, legumes, and whole-grain cereals (Carson-DeWitt 2004).
Tryptophan is an amino acid found in most proteins. It is classified as an "essential amino acid" since it cannot be synthesized by the human body from other compounds through chemical reactions and thus has to be taken in with the diet. Tryptophan is found in soybeans, meat, poultry, fish, and eggs. If one's diet contains these foods, one's need for niacin from other sources will be reduced (Haas 1992). Conversion of tryptophan to niacin is insufficient by itself to fully meet the demands for this vitamin, but it can help forestall pellagra. Lack of tryptophan, however, such as dependence on food of low tryptophan content such as maize (corn), can contribute to this niacin-deficiency disease.
Pellagra can be common in people who obtain most of their food energy from corn, since untreated corn is a poor source of niacin. Corn is also a poor source of tryptophan. This disease can be common among people who live in rural South America where corn is a staple.
It is one of several diseases of malnutrition common in Africa. It was also endemic in the poorer states of the U.S. South, like Mississippi and Alabama, as well as among the inmates of jails and orphanages, where it was studied by Joseph Goldberger who conducted experiments in the penal colony in Rankin. Alkali treatment of the corn corrects the niacin deficiency, and this was a common practice in Native American cultures that grew corn. Pellagra was common among prisoners of Soviet labor camps, the infamous Gulag. It can be found in cases of chronic alcoholism.
The relationship between leucine and pellagra is unclear (Bapurao and Krishnaswamy 1978).
Pellagra causes a number of symptoms affecting the skin, mucous membranes, central nervous system, and gastrointestinal tract. Common symptoms include:
- High sensitivity to sunlight
- Dermatitis, alopecia, oedema
- Smooth, beefy red glossitis
- Red skin lesions
- Mental confusion and memory loss
- Ataxia, paralysis of extremities, peripheral neuritis
- Eventually dementia
The main results of pellagra can easily be remembered as "the four D's": diarrhea, dermatitis, dementia, and death (Hegyi et al. 2004).
Early patients may have only a light skin rash, but over time the skin becomes progressively thickened and pigmented, and may slough off in places. The mouth and tongue, and sometimes the vagina, may become progressively swollen, red, and thickened. There may be abdominal pain, nausea, and vomiting, and bloody diarrhea (Carson-DeWitt 2004).
There are a number of mental changes associated with pellagra. This includes insomnia, fatigue, and apathy, progressing to memory loss, confusion, depression and hallucination (Carson-DeWitt 2004). There also may be impressions as being painful, annoying bright lights, odors intolerance, dizziness after sudden movements, restlessness, tenseness and a desire to quarrel (Cleary and Cleary 1989). There may be the development of involuntary grasping and sucking movements and variations in level of consciousness (Carson-DeWitt 2004).
Diagnosis, treatment, and prognosis
Diagnosis is based on patient diet history as well as patients recollection of symptoms. There are no chemical tests, but the patient can be placed on a diet sufficient in niacin and seeing the response of the patient (Carson-DeWitt 2004).
Treatment of pellagra involves supplementing the diet, often with a form of niacin called niacinamide, since pure niacin has unpleasant side effects. It can be given orally or by injection (Carson-DeWitt 2004). The frequency and amount of niacinamide administered depends on the degree to which the condition has progressed.
Untreated, the disease will continue progressing and can kill within four or five years. Death often is due to complications from infections, blood loss, sever encephalophatic syndrome, or massive 