Nicotinic acid plays a crucial role in the cellular process
called respiration. Respiration is the process by which
nutrients (specifically sugar, or glucose) and oxygen are taken
in, chemical reactions take place, energy is produced and
stored, and carbon monoxide and wastes are given off. This
process is absolutely central to basic cell functioning, and
thus the functioning of the body as a whole. Niacin is a B
vitamin found in such foods as yeast, liver, meat, fish, whole-
grain cereals and breads, and legumes. Niacin can also be
produced within the body from the essential amino acid called
tryptophan. Dietary requirements for niacin depend on the age,
gender, size, and activity level of the individual. Niacin
requirements range from 5 mg in infants up to 20 mg in certain
adults. Causes and symptoms Pellagra can be either primary or
secondary. Primary pellagra results when the diet is extremely
deficient in niacin-rich foods. A classic example occurs in
geographic locations where Indian corn (maize) is the