Definitions for niacinˈnaɪ ə sɪn
This page provides all possible meanings and translations of the word niacin
niacin, nicotinic acid(noun)
a B vitamin essential for the normal function of the nervous system and the gastrointestinal tract
A water-soluble vitamin, a component of vitamin B complex, found in meat, yeast, and dairy products; it is essential to metabolism.
Niacin is an organic compound with the formula C 6H 5NO 2 and, depending on the definition used, one of the 40 to 80 essential human nutrients. Niacin is one of five vitamins associated with a pandemic deficiency disease: niacin deficiency, vitamin C deficiency, thiamin deficiency, vitamin D deficiency, vitamin A deficiency. Niacin has been used for over 50 years to increase levels of HDL in the blood and has been found to modestly decrease the risk of cardiovascular events in a number of controlled human trials. This colorless, water-soluble solid is a derivative of pyridine, with a carboxyl group at the 3-position. Other forms of vitamin B3 include the corresponding amide, nicotinamide, where the carboxyl group has been replaced by a carboxamide group, as well as more complex amides and a variety of esters. Nicotinic acid and niacinamide are convertible to each other with steady world demand rising from 8500 tonnes per year in 1980s to 40,000 in recent years. Niacin cannot be directly converted to nicotinamide, but both compounds could be converted to NAD and NADP in vivo. Nicotinic acid, nicotinamid, and tryptophan are co-factors for nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate. NAD converts to NADP by phosphorylation in the presence of the enzyme NAD+ kinase. NADP and NAD are coenzyme for many dehydrogenases, participating in many hydrogen transfer processes. NAD is important in catabolism of fat, carbohydrate, protein and alcohol as well as cell signaling and DNA repair and NADP mostly in anabolism reaction such as fatty acid and cholesterol synthesis. High energy requirements or high turnover rate organs are usually the most susceptible to their deficiency. Although the two are identical in their vitamin activity, nicotinamide does not have the same pharmacological effects as niacin. Nicotinamide does not reduce cholesterol or cause flushing. Nicotinamide may be toxic to the liver at doses exceeding 3 g/day for adults. Niacin is a precursor to NAD+/NADH and NADP+/NADPH, which play essential metabolic roles in living cells. Niacin is involved in both DNA repair, and the production of steroid hormones in the adrenal gland.
U.S. National Library of Medicine
A water-soluble vitamin of the B complex occurring in various animal and plant tissues. It is required by the body for the formation of coenzymes NAD and NADP. It has PELLAGRA-curative, vasodilating, and antilipemic properties.
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