History and discovery of vitamin B3 (niacin)

Pellagra was first described in Spain by Don Gaspar Casal in 1735 after the introduction of maize into Europe from the America. Pellagra has sometimes been called the disease of the four Ds – dermatitis, diarrhoea, dementia and death.

In the 1920s, Goldberger in the United States reported that pellagra and black tongue in dogs responded to treatment with animal protein and also to boiled protein-free extracts of yeast.

Niacin was first described by chemist Hugo Weidel in 1873. It was extracted by Casimir Funk in 1912 while he was trying to find a cure for another disease known as beriberi, but he thought it to be thiamine.

Casimir Funk abandoned his work after finding that nicotinic acid had no effect on beriberi.

In 1915, American epidemiologist and US Public Health Service officer Joseph Goldberger conducted a classic series of observational and experimental studies in humans, combined with an extensive series of experiments with an animal model of the condition (black tongue in dogs).

Afterward, Conrad Elvehjem a biochemist from Wisconsin in 1937 extracted an active ingredient from livers that was referred as ‘pellagra-preventing factor’ and the ‘anti-black tongue factor’ called niacin.

In general, it has been termed as ‘vitamin PP,’ ‘vitamin P-P,’ and ‘PP factor.’ The name niacin comes from nicotinic acid + vitamin, to distance itself from the word nicotine, which the public knows as a toxic chemical found in tobacco.
History and discovery of vitamin B3 (niacin)

Functions of niacin in human body

Niacin (also known as vitamin B3) is the generic name for nicotinic acid (pyridine-3-carboxylic acid), nicotinamide (niacinamide or pyridine-3-carboxamide), and related derivatives, such as nicotinamide riboside.

Niacin is required for cell respiration and helps in the release of energy and metabolism of carbohydrates, fats and proteins, proper circulation, maintenance of healthy skin, functioning of the nervous system and normal secretion of bile and stomach fluids. Niacin is important for the development and function of the cells.

A sufficient intake of vitamin B3 (niacin) is important as it helps the body to
• convert food into glucose, used to produce energy
• produce macromolecules, including fatty acids and cholesterol
• DNA repair and stress responses.

Niacin is found in multivitamin/multimineral supplements. It is also available in B-complex dietary supplements and supplements containing only niacin. The two main forms of niacin in dietary supplements are nicotinic acid and nicotinamide.
Functions of niacin in human body

Niacin: An essential human nutrient

Niacin (also known as “vitamin B3” or “vitamin PP”) is the generic descriptor for two vitamers, nicotinic acid (pyridine-3-carboxylic acid) and nicotinamide (nicotinic acid amide).

Niacin is quickly and easily absorbed from the intestinal tract and distributed extensively to body tissue after being hepatically metabolized. It is converted by the body to its active coenzyme forms, nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate.

NAD and NADP where their oxidized forms, that is, NAD+ and NADP+ play an essential role in many biochemical reactions. The two coenzymes are required for oxidative reactions crucial for energy production, but they are also substrates for enzymes involved in non-redox signaling pathways, thus regulating biological functions, including gene expression, cell cycle progression, DNA repair and cell death.

Niacin is a B vitamin that's made and used by human body to turn food into energy. It is required for cell respiration and helps in the release of energy and metabolism of carbohydrates, fats and proteins, proper circulation, maintenance of healthy skin, functioning of the nervous system and normal secretion of bile and stomach fluids.

Niacin also helps the body make sex- and stress-related hormones and improves circulation and cholesterol levels.

Clinical evidence of niacin deficiency includes fatigue, poor appetite, diarrhea, irritability, headache, emotional instability and possible memory loss. These may lead to changes in the skin, mucosa of the mouth, stomach and intestinal tract and the nervous system.
Niacin: An essential human nutrient

Food sources of vitamin B3

Niacin, also known as vitamin B3, the third water-soluble vitamin discovered. Niacin is the generic term for nicotinic acid (pyridine 3-carboxylic acid) and nicotinamide (nicotinic acid amide). Both are used to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) which play essential roles for the development and function of living cells in human body.

Niacin is found naturally in many foods, and is added to some foods.
• Poultry, beef, pork, anchovies and fish
• Some types of peanuts, nuts, legumes, and grains
• Enriched and fortified foods, such as many breads and cereals
• Whole grains and whole meal wheat flour

In general, food rich in protein, with the exception of tryptophan-poor grains (e.g., corn, wheat), can satisfy some of the requirement for niacin. Important food sources of tryptophan are meat, milk and eggs.

The amino acid tryptophan contributes as much as two thirds of the niacin activity required by adults in typical diets.

Peanut butter is an excellent source of niacin. Fruits and vegetables provide useful amounts, depending upon the dietary intake. Other useful sources are whole grain cereals, bread, tea, and coffee.

Human milk contains a higher concentration of niacin than cow’s milk. In plants, especially in mature cereal grains like corn and wheat, niacin may be bound to sugar molecules in the form of glycosides, thus significantly reducing niacin bioavailability.

B3 (niacin) is important as it helps the body to
• convert food into glucose, used to produce energy
• produce macromolecules, including fatty acids and cholesterol
• DNA repair and stress responses.

Most people in the United States get enough niacin from the foods they eat. Niacin deficiency is very rare in the United States.
Food sources of vitamin B3

Lack of niacin can cause pellagra

Pellagra results from a niacin and/or tryptophan deficient diet which produces psychosis and dementia, among other symptoms. Niacin, known as vitamin B3, is a water-soluble, vitamin of the B complex group of vitamins.

The earliest description of pellagra was that of the Spanish physician Don Gaspar Casal in 1763.Casal recorded all the clinical characteristics and ascribed the disease to the unbalanced diets, based on maize, of poor peasants in the Asturia region of Spain. The next description of the disease came from Italy in 1771 when pellagra was given its name, meaning "rough skin".

Pellagra mostly found in parts of India, China, and Africa where corn or maize as a staple food. The characteristic manifestations appear as dermatitis, diarrhea and dementia ("the three Ds") and can lead to death (the fourth D).

Causes of pellagra can be divided into primary and secondary. Primary pellagra is due to dietary deficiency. High leucine content in corn/maize prevents conversion of tryptophan to niacin, leading to deficiency of niacin. Secondary pellagra is due to defective absorption or metabolism of niacin/tryptophan.

Early neurological symptoms associated with pellagra include anxiety, depression, and fatigue; later symptoms include apathy, headache, dizziness, irritability and tremors. In early cases the manifestations are psychoneurotic; later, lesions affect the nerves. As the disease advances, patients become confused, disoriented, and delirious, then comatose and stuporous, and finally die.

Mental aberrations may pass to dementia: about 4-10 % of chronic pellagra patients developmental symptoms.

In the western world, it is almost eradicated due to fortification of flour with niacin.

Lack of niacin can cause pellagra