Vitamin B3 - Niacin

There are several forms of vitamin B3. Nicotinic acid (which is also known as niacin) is very closely related to the other compound nicotinamide or niacinamide. They all have vitamin B3 activity but nicotinic acid has rather specific effects on cholesterol metabolism.

Although vitamin B3 was discovered in 1911 its full role as a vitamin was not appreciated until 1937. Classical deficiencies of vitamin B3 produces pellagra (a condition characterized by dermatitis, diarrhea and dementia).

The functions of vitamin B3 (niacin)

Vitamin B3 is important for:

the proper functioning of the nervous system and therefore the brain;
the health of the skin;
improving circulation;
the metabolism of carbohydrates, fats and proteins;
making sex hormones, and cortisol, thyroxine and insulin;
the production of hydrochloric acid; and
the normal secretion of bile and digestive fluids.

Vitamin B3 is available in two forms, niacin and niacinamide. The body's need for vitamin B3 is satisfied by either form, but in doses larger than those obtained from food, they have very different effects in the body.

Niacin lowers LDL cholesterol and triglycerides, increases beneficial HDL cholesterol, increases circulation, improves brain function by improving the oxygen carrying ability of the red blood cells, regulates blood flow in memory tissue, and has the ability to mobilize fat from cells into the blood. Niacin also strengthens GABA, which is a calming neurotransmitter. The niacin form of B3 can cause flushing of the skin.

Niacinamide does not cause flushing, will not lower cholesterol or improve circulation, but has other benefits. It has been used since the 1940's to reduce insulin requirements of diabetics and has been found to be very effective in the treatment of osteoarthritis.

The symptoms and signs of a vitamin B 3 deficiency

A severe deficiency of vitamin B3 and the amino acid tryptophan will result in pellagra, which manifests itself in marked dermatitis, dementia, and diarrhea. A moderate deficiency can cause these symptoms to a lesser degree including:

insomnia,
tired all the time syndrome (T.A.T.),
poor appetite,
digestive problems,
muscle weakness,
irritability,
skin problems,
mouth sores, and
psychiatric disturbances (vitamin B3 deficiency has been linked to schizophrenia and depression).

Therapeutic uses

Vitamin B3 is used in the following conditions:

menstrual pain and irregularities,
skin problems,
migraine headaches,
circulatory problems and high blood pressure,
vertigo in Meniere's syndrome,
tinnitus (ringing or booming sensation in one or both ears)
mouth ulcers,
high cholesterol,
some types of diabetes, and
wheezing in asthmatics.

Food sources of vitamin B3

Niacin is found in: brewer's or nutritional yeast, liver, broccoli, carrots, cheese, eggs, fish, raw milk, peanuts, potatoes, tomatoes, dandelion greens, and wheat germ.

How much do you need?

It is best to take vitamin B3 as part of vitamin B complex and increase your intake if you are pregnant, breast feeding, in your child bearing years or on the contraceptive pill. 50-100 mg is usually adequate although higher doses may be recommended for particular conditions.

Contraindications - When NOT to take extra B3

Those suffering from diabetes, glaucoma, gout, liver disease, or peptic ulcers should use niacin supplements cautiously.

Consuming over 500 mg per day for an extended length of time may result in liver damage.

Special notes

Alcohol inhibits the metabolism of niacin and sleeping pills, estrogen and food processing will destroy the vitamin.
High doses of nicotinic acid and nicotinamide can alter liver function tests, changes which quickly reverse when treatment is stopped or the dosage reduced.
Some studies indicate that doses higher than 500 mg may cause some liver damage.

References

Bland, J. 1996, Contemporary Nutrition. J & B Associates.

Davies, S. and A. Stewart., 1997, Nutritional Medicine. Pan.

Holden, S., Hudson, K., Tilman, J. & D. Wolf, 2003, The Ultimate Guide to Health from Nature. Asrolog Publication.

Pressman, A. and S. Buff, 2000, The Complete Idiot's Guide to Vitamins and Minerals. (2nd Ed.) Alpha Books.

Soothill, R. 1996, The Choice Guide to Vitamins and Minerals. A Choice Book Publication.

Sullivan, K. 2002, Vitamins and Minerals: A Practical Approach to a Health Diet and Safe Supplementation. Harper Collins.