Niacin, or vitamin B-3 is a generic term used to refer to two different compounds,
nicotinic acid and niacinamide. Either form is converted in the body to the
physiologically active forms that are required in many metabolic processes.
Niacin is involved in the metabolism of carbohydrates, protein and fat and the
generation of energy from foods. Niacin is needed in the formation of red blood cells and
some hormones, and in the metabolism of some drugs and toxicants. Niacin is also required
in the production of hydrochloric acid.
Niacin also supports normal central nervous system function and is important to the
health of the skin and helps maintain normal digestive tract function.
Niacin can be manufactured in the body from the essential amino acid
Niacin deficiency is a disease called pellagra. Pellagra is the disease of the three
Ds, diarrhoea, dermatitis, and dementia. Niacin deficiency affects every cell, especially
where there is rapid cell turnover, such as the skin, GI tract, and nervous system.
Some characteristics of pellagra include decreased energy and problems maintaining the
integrity of the skin and intestinal tract. Symptoms include weakness and fatigue,
anorexia, indigestion, and skin irregularities. These can progress to canker sores,
nausea, vomiting, and diarrhea. Reduced stomach acid production will contribute to
malabsorption of a number of nutrients including fat, and fat soluble vitamins. The
neurological symptoms initially are irritability, insomnia, with headaches and can
progress to extreme anxiety, depression and psychosis.
Niacin, in the form of nicotinic acid can produce a niacin flush. This is a redness,
warmth, and itching to the skin. This typically happens when the dosage is 50 mg or
higher. The flush is the result of vasodilation. While some find this feeling
uncomfortable, it is harmless.
Nicotinic acid stimulates circulation, helps maintain normal blood pressure and blood
triglyceride levels. Nicotinic acid is very effective at lowering LDL cholesterol while
raising HDL cholesterol, both of which support normal cholesterol levels.
Niacin has been important to the field of orthomolecular nutrition for its use
supporting the higher functions of the brain and cognition. While niacin was originally
helpful for the dementia of pellagra, high doses have been used to support normal mood and
psychological function. This continues to be a controversy, though there are some studies
that showed promising results.