In the search to find the cause of pellagra, a common disease in 18th and early 19th century Spain, Italy and America, researchers stumbled upon nicotinamide (or niacin, as it has become generically known).
Niacin, or vitamin B3 as it used to be called, was the solution. The shortage of this vitamin, which can be found in protein-rich foods, was fully recognised as the cause of pellagra by 1937.
More recently, it was found that a precursor of niacin, called tryptophane, is also involved in the prevalence of the disease. Tryptophane is an amino acid (in other words, one of the building blocks of protein).
Tryptophane is called a "precursor", because dietary tryptophane can be converted into niacin in the body.
Niacin is one of the B-complex vitamins, all of which play an essential role in metabolism.
Like all the other B-complex vitamins and vitamin C, niacin is water-soluble. The B-complex vitamins are grouped together because of their similar physical properties and their presence in similar food sources.
Because of the close inter-relationship between the B-complex vitamins, it is important to note that the inadequate intake of one of the vitamins can result in the impaired utilisation of the others.