Vitamin B3
Niacin
Year of discovery: 1937 | Conrad Elvehjem
Niacin acts as a coenzyme in energy transfer reactions, especially in the metabolism of glucose, fats and alcohol. Niacin is similar to the coenzyme riboflavin in that it transfers hydrogen molecules (and their electrons) during metabolic reactions. It also protects against neurological degeneration. Niacin is unique in that it can also be synthesized from the amino acid tryptophan. It comes in two forms: niacinamide and nicotinic acid.
Main sources of vitamin B3
The main sources are offal (liver), fish, meat, milk, eggs, whole grains, legumes, fruits (avocados, figs, dates, dried prunes) and nuts. Other: synthesized from tryptophan.
Bioavailability of vitamin B3
Absorption of niacin depends on the food source. Niacin from meat, liver, beans and products enriched with it is highly bioavailable. About 30% of the niacin in grains is bioavailable. Additional niacin content can be released if foods are subjected to alkaline treatment (lime water / calcium hydroxide). Compared to other water-soluble vitamins, niacin is less susceptible to a decrease in its content in the food product during food storage. It is quite resistant to heat, so it will withstand not very long cooking times. Like other water-soluble vitamins, it leaches into water during cooking.
Risks associated with insufficient or excessive intake of vitamin B3
People whose energy needs are not met by an adequate diet are at risk of deficiency. The situation is similar in people whose staple diet is based mainly on (unprocessed) corn or barley, as well as in compulsive alcoholics. Severe niacin deficiency causes a disease called pelagra, and its symptoms are skin inflammation, diarrhea, dementia and eventually death. The risk of overconsumption is unlikely if niacin is taken from food sources. Consumption of niacin in the form of nicotinic acid from multiple sources in large amounts, including dietary supplements, pharmaceutical doses and fortified foods, can cause side effects such as hot flashes, nausea and vomiting, liver damage, blurred vision and impaired glucose tolerance.
