Vitamin pellagra

Many molecular diseases that have arisen in the course of evolution have been controlled in a somewhat similar manner. Human beings require many vitamins. Pellagra is an example of a vitamin deficiency disease—a molecular disease that originated through a mutation, perhaps millions of years ago, and was then cured by the heterotrophic process of eating other organisms that manufacture the vitamin. Scurvy and other avitaminoses are also diseases of this sort. It is not customary for us to admit that we have these diseases, because we treat them as a matter of habit by eating what is called a proper diet. 

Our word vitamin was coined m 1912 m the belief that the substances present m the diet that prevented scurvy pellagra beriberi rickets and other diseases were vital amines In many cases that belief was confirmed certain vitamins did prove to be amines In many other cases however vitamins were not amines Nevertheless the name vitamin entered our language and stands as a reminder that early chemists recognized the crucial place occupied by amines m biological processes... 

In this period, the empirical healing of certain diseases by foods was estabUshed. Examples (3) were the treatment of night blindness (vitamin A deficiency) with hver ia many cultures over centuries, of beriberi (vitamin deficiency) by use of unpoHshed rice by the Japanese navy, of scurvy (vitamin C deficiency) by citms fmits ia the British navy or piae needle extracts by North American natives, and pellagra (niacia deficiency) by a dietary shift away from corn-based foods ia many countries. Other, nondietary empirical treatments iavolved, eg, exposure of children ia northern latitudes to sunlight to cute tickets (vitamin D deficiency) (4). 

Niacin is recommended to alleviate pellagra, a disease caused by a deficiency of this vitamin. 

The water-soluble vitamins comprise the B complex and vitamin C and function as enzyme cofactors. Fofic acid acts as a carrier of one-carbon units. Deficiency of a single vitamin of the B complex is rare, since poor diets are most often associated with multiple deficiency states. Nevertheless, specific syndromes are characteristic of deficiencies of individual vitamins, eg, beriberi (thiamin) cheilosis, glossitis, seborrhea (riboflavin) pellagra (niacin) peripheral neuritis (pyridoxine) megaloblastic anemia, methyhnalonic aciduria, and pernicious anemia (vitamin Bjj) and megaloblastic anemia (folic acid). Vitamin C deficiency leads to scurvy. 

Niacin was discovered as a nutrient during studies of pellagra. It is not strictly a vitamin since it can be synthesized in the body from the essential amino acid tryptophan. Two compounds, nicotinic acid and nicotinamide, have the biologic activity of niacin its metabolic function is as the nicotinamide ring of the coenzymes NAD and NADP in oxidation-reduction reactions (Figure 45-11). About 60 mg of tryptophan is equivalent to 1 mg of dietary niacin. The niacin content of foods is expressed as mg niacin equivalents = mg preformed niacin + 1/60 X mg tryptophan. Because most of the niacin in cereals is biologically unavailable, this is discounted. 

June, 1912 Casimir Funk, a Polish biochemist working in London, England, wrote a review article in which he elaborated on the fact that diseases such as scurvy, beri-beri, rickets and pellagra had long been known to be associated with the dietary. Funk said that these diseases could be prevented or cured by adding certain organic substances to the diet, substances he called vitamines. 0 )... 

The last of the B vitamins to be identified in the water-soluble vitamin complex from milk was pyridoxine, vitamin B6 (Birch and Gyorgy, 1936). This was needed to prevent a type of dermatitis in rats which was different from pellagra or acrodynia and could be accompanied by convulsions. Much of the early work on the mode of action of this vitamin came from experiments on microbial metabolism (Chapter 6). 

Pellagra in the United States is now very rare, the consequence of the good work of Joseph Goldberger and others and of more balanced diets and the vitamin fortification of many foods. 

Oxidation of nicotine with chromic acid led to the isolation of pyridine-3-carboxylic acid, which was given the trivial name nicotinic acid. We now find that nicotinic acid derivatives, especially nicotinamide, are biochemically important. Nicotinic acid (niacin) is termed vitamin B3, though nicotinamide is also included under the umbrella term vitamin B3 and is the preferred material for dietary supplements. It is common practice to enrich many foodstuffs, including bread, flour, corn, and rice products. Deficiency in nicotinamide leads to pellagra, which manifests itself in diarrhoea, dermatitis, and dementia. 

Nicotinate and nicotinamide, together referred to as niacin, are required for biosynthesis of the coenzymes nicotinamide adenine dinucleotide (NAD"") and nicotinamide adenine dinucleotide phosphate (NADP" ). These both serve in energy and nutrient metabolism as carriers of hydride ions (see pp. 32, 104). The animal organism is able to convert tryptophan into nicotinate, but only with a poor yield. Vitamin deficiency therefore only occurs when nicotinate, nicotinamide, and tryptophan are all simultaneously are lacking in the diet. It manifests in the form of skin damage (pellagra), digestive disturbances, and depression. 

Pyridoxine is indicated in vitamin B deficiency, for the treatment of some pyridoxine responsive anemia s and for isoniazid-induced neuropathy. It may relieve symptoms of pellagra when niacin fails. Long-term administration of large doses may produce neurotoxicity manifesting itself in progressive peripheral sensory neuropathy. 

Nicotine forms a number of metabolites in the body, mainly in the liver. Approximate 75% of nicotine is oxidized to cotinine, which is the primary nicotine metabolite. Cotinine can be measured in the blood, urine, and saliva and this is used as a measure of nicotine exposure in tobacco users and in those exposed to secondhand smoke. The oxidation of nicotine also produces nicotinic acid. Nicotinic acid is vitamin B3 and has the common name niacin. Niacin deficiency results in a disease called pellagra, which is found in certain malnourished populations. Pellagras symptoms include dermatitis, diarrhea, sensitivity to light, and dementia. 

The classical niacin deficiency disease is pellagra, which is characterized by symptoms including diarrhoea, dermatitis, dementia and eventually death. High-protein diets are rarely deficient in niacin since, in addition to the preformed vitamin, such diets supply sufficient tryptophan to meet dietary requirements. Large doses of niacin can cause the dilation of capillaries, resulting in a painful tingling sensation. 

Dietary Deficiency of Niacin, the Vitamin Form of NAD and NADP, Causes Pellagra... 

Niacin (nicotinic acid, nicotinamide) has the active forms NAD and NADPH. It functions in electron transfer. A deficiency of niacin causes pellagra, which is characterized by der matitis, diarrhea, and dementia. There is no known toxicity for this vitamin. High doses of niacin are used to treat hyperlipidemia. 

Two vitamins, nicotinamide and pyridoxine (vitamin B6), are pyridine derivatives. Nicotinamide participates in two coenzymes, coenzyme I (65 R = H) which is known variously as nicotinamide adenine dinucleotide (NAD) or diphosphopyridine nucleotide (DPN), and coenzyme II (65 R = P03H2) also called triphosphopyridine nucleotide (TPN) or nicotinamide adenine dinucleotide phosphate (NADP). These are involved in many oxidation-reduction processes, the quaternized pyridine system acting as a hydrogen acceptor and hydrogen donor. Deficiency of nicotinamide causes pellagra, a disease associated with an inadequately supplemented maize diet. Nicotinic acid (niacin) and its amide are... 

Riboflavin was found to be most responsible for the stimulation of rat growth, while vitamin B6 was needed to prevent a facial dermatitis or "rat pellagra." Pantothenic acid was especially effective in curing a chick dermatitis, while nicotinamide was required to cure human pellagra. Biotin was required for growth of yeast. 

Pellagra - DYES, NATURAL] (Vol 8) - [VITAMINS - NIACINE,NICOTINAMIDEANDNICOTINIC ACID] (Vol 25) - [WHEAT AND OTHER CEREAL GRAINS] (Supplement) -vitamins as treatment [VITAMINS - SURVEY] (Vol 25)... 

VITAMIN B2 (Riboflavin). Some earlier designations for this substance included vitamin G, lactoflavin, hepatoflavin, ovoflavin, veidoflavin. The chemical name is 6,7-dimcthyl-9-d-l ribityl isolloxazine. Riboflavin is a complex pigment with a green fluorescence. Riboflavin deficiency frequently accompanies pellagra and the typical lesions of both nicotinic acid and riboflavin deficiency are found in that disease. See also Niacin. 

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