Niacin vitamin deficiency

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. 

L12. Ludovici, P. P., and Axelrod, A. E., Circulating antibodies in vitamin-deficiency states. Fteroylglutamic acid, niacin-tryptophan, vitamins B12, A, and D deficiencies. Proc. Soc. Exp. Biol. Med. 77, 526-530 (1951). 

NAD+, derived from niacin and coenz)rme A, derived from pantothenic acid. Obviously, a deficiency in any of these vitamins would seriously reduce the amount of acetyl CoA that our cells could produce. This, in turn, would limit the amount of ATP that the body could make and would contribute to vitamin-deficiency diseases. Fortunately, a well-balanced diet provides an adequate supply of these and other vitamins. 

As mentioned, some patients have documented deficiencies of several vitamins. Indeed, isolated clinically significant deficiency of a single vitamin is probably rare. Yet the import of multiple deficiencies is not always clear. Even for the best recognized avitaminoses, such as pellagra or the Wernicke-Korsakoff syndrome, defects in cognition are attributable to lack of more than just the one classically implicated vitamin. Deficiency of multiple water soluble vitamins pertains especially to alcoholics, to the elderly, and to severely ill hospitalized patients. For example, low folate stores, combined with inadequate niacin and thiamine, probably contribute to the chronic memory disorder of alcoholism. 

The criteria for the diagnosis of vitamin deficiency are specific for every single vitamin. However, some common rules can be applied to most of the B vitamins. First, it has to be stated that, in clinical practice, some vitamins (biotin, pantothenic acid, niacin) are hardly ever measured and therefore data on vitamin status are hardly available. Other vitamins like folate and cobalamin are measured regularly using commercial assays. 

Since the start of the enrichment program in 1941, the available supplies of the B vitamins— thiamin, riboflavin, and niacin—and of iron in the national diet have increased. The enrichment program has played a significant role in the practical elimination of the vitamin deficiency diseases ariboflavi-nosis, beriberi, and pellagra, and of simple iron deficiency anemia. 

The possibility that vitamins might have physiological functions beyond the prevention of deficiency diseases was first recognized in 1955 with the finding (8) that niacin can affect semm cholesterol levels in humans. An explosion of research (9—11) in the intervening years has been aimed at estabUshing optimal vitamin levels and anticipating the health consequences. 

In terms of amino acids bacterial protein is similar to fish protein. The yeast s protein is almost identical to soya protein fungal protein is lower than yeast protein. In addition, SCP is deficient in amino acids with a sulphur bridge, such as cystine, cysteine and methionine. SCP as a food may require supplements of cysteine and methionine whereas they have high levels of lysine vitamins and other amino acids. The vitamins of microorganisms are primarily of the B type. Vitamin B12 occurs mostly hi bacteria, whereas algae are usually rich in vitamin A. The most common vitamins in SCP are thiamine, riboflavin, niacin, pyridoxine, pantothenic acid, choline, folic acid, inositol, biotin, B12 and P-aminobenzoic acid. Table 14.4 shows the essential amino acid analysis of SCP compared with several sources of protein. 

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. 

A vitamin is defined as an organic compound that is required in the diet in small amounts for the maintenance of normal metabofic integrity. Deficiency causes a specific disease, which is cured or prevented only by restoring the vitamin to the diet (Table 45-1). However, vitamin D, which can be made in the skin after exposure to sunhght, and niacin, which can be formed from the essential amino acid tryptophan, do not stricdy conform to this definition. 

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. 

The answer is B. While all of the listed conditions are consistent with lethargy and developmental defects, the lactic acidosis rules out pyruvate kinase deficiency. Thiamine and niacin deficiencies are unlikely due to the lack of effect of vitamin supplementation. Excess pyruvate is the source of the elevated alanine in the serum. The clinical findings are thus consistent with pyruvate carboxylase deficiency, which is associated with severe hypoglycemia due to fasting due to impaired gluconeogenesis. 

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. 

Other vitamins—vitamin R6 and niacin—complement folic acid. Vitamin R6 deficiency apparently causes chromosome breaks by the same mechanism as folate deficiency.43 Niacin is... 

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