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The Benefits of Vitamin B3 (niacin)
By: Dr. Obikoya
Vitamin B3 is a water-soluble vitamin vital for energy
release in tissues and cells. It belongs to the B complex group of vitamins. It
is also called the pellagra-preventive vitamin, or vitamin PP, because an
adequate amount in the diet prevents pellagra, a chronic disease characterized
by skin lesions, gastrointestinal disturbance, and nervous symptoms.
Niacin, aka Vitamin B3, comes in two basic interchangeable forms — niacin
(also called nicotinic acid) and niacinamide (also called nicotinamide). A
variation on niacin, called inositol hexaniacinate, is also available in
supplements. Some doctors recommend inositol hexaniacinate for people who need
large amounts of niacin because it has not been linked with any of the usual
niacin toxicity in scientific research.
Like vitamin Like vitamin B1 (thiamine) and vitamin B2 (riboflavin), it is a
coenzyme involved in the metabolism of carbohydrates and acts to catalyze the
oxidation of sugar derivatives and other substances.
Niacin, which was identified as a pellagra preventive in 1937. We need about 10
to 20 milligrams per day (1 milligram = 0.001 gram) of nicotinic acid. In the
intestinal tract, the amino acid tryptophan can be converted to niacin by
bacterial action and thus can serve as a source for part of the niacin we need.
This explains scientists' early observation that the protein in such foods as
eggs and milk, both poor sources of niacin, can nevertheless prevent or cure
pellagra in humans.
Niacin is one of the most stable vitamins. It helps form NAD (nicotinamide
adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate),
coenzymes which are involved in the release of energy and food. These compounds
help to maintain a healthy nervous and digestive system. Vitamin B3 is essential
for normal growth and for healthy skin.
Vitamin B3 is required for the proper function of more than 50 enzymes. Without
it, your body would not be able to release energy or make fats from
carbohydrates. Vitamin B3 is also used to make sex hormones and other important
chemical signal molecules.
A deficiency of niacin causes pellagra, the first symptom of which is a
sunburn-like eruption that breaks out where the skin is exposed to sunlight.
Later symptoms are a red and swollen tongue, diarrhea, mental confusion,
irritability, and, when the central nervous system is affected, depression and
mental disturbances.
The body makes niacin from the amino acid tryptophan. Megadoses of niacin have
been used to treat schizophrenia. In large amounts, sometimes more than 1,000
milligrams a day, niacin has been shown to reduce LDL cholesterol (the 'bad'
cholesterol that clogs the heart's arteries) and triglycerides and raise HDL
cholesterol (the 'good' cholesterol that prevents hardening of the artery
walls)1. Niacin has been used extensively in preventing and treating
arteriosclerosis. Additionally, good evidence suggests that a special form of
niacin, inositol hexaniacinate, can improve walking distance in intermittent
claudication. It may also reduce symptoms of Raynaud's phenomenon.
High-dose niacinamide is helpful in preventing type 1 (childhood-onset)
diabetes2 and reducing symptoms of osteoarthritis3 However, you should only take
increased doses of niacin under the supervision of a physician as too large
doses over long periods may cause liver damage.
Women should have 15 milligrams each day and men should have 15 to 19 milligrams
each day. Tryptophan is an amino acid that serves as a Vitamin B3 equivalent.
Sixty milligrams of tryptophan is equal to 1 milligram of vitamin B3.
Doses of over 150mg of the nicotinic acid form may cause temporary flushing of
the skin in some people. Upper safe level: nicotinamide - 450mg (long term
usage); 1500 mg (short term usage). Nicotinic acid - 150mg (long term usage);
500mg (short term usage)
The antituberculosis drug isoniazid (INH) impairs the
conversion of tryptophan to niacin, and may produce symptoms of niacin
deficiency.
When used as therapy for a specific disease, niacin, niacinamide, and inositol
hexaniacinate are taken in dosages much higher than nutritional needs, about 1
to 4 g daily. Because of the risk of liver inflammation at these doses, medical
supervision is essential.
For prevention of diabetes in children, the usual dosage of niacinamide is 25 mg
per kilogram body weight per day. There are 2.2 pounds in a kilogram, so a
40-pound child would get about 450 mg daily. Medical supervision is essential
before giving your child long-term niacinamide treatment.
Many people experience an unpleasant flushing sensation and headache when they
take niacin. These symptoms can usually be reduced by gradually increasing the
dosage over several weeks or by using slow-release niacin. However, slow-release
niacin appears to be more likely to cause liver inflammation than other forms.
Inositol hexaniacinate may also cause less flushing than plain niacin, and if
you take an aspirin along with niacin, the flushing reaction will usually
decrease.
References
1. Guyton JR, Goldberg AC, Kreisberg RA, et al. Effectiveness of once-nightly
dosing of extended-release niacin alone and in combination for
hypercholesterolemia. Am J Cardiol 82: 737–743, 1998.
2. Elliott RB, Pilcher CC, Fergusson DM, et al. A population based strategy to
prevent insulin-dependent diabetes using nicotinamide. J Pediatr Endocrinol
Metab 9: 501–509, 1996.
3. Jonas WB, Rapoza CP, and Blair WF. The effect of niacinamide on
osteoarthritis: a pilot study. Inflamm Res 45: 330–334, 1996.
