Vitamin (water-soluble)

• UK RNI 18 mg
• US RDA 19 mg

Functions

• Conversion of carbohydrate to energy
• DNA synthesis
• Health of skin, nerves, brain and digestive system
• Synthesis of fatty acids and steroids.

Good food sources

• Beef liver
• Chicken
• Meat
• Nuts
• Peanuts
• Salmon and other oily fish
• Sunflower seeds
• Wholegrains

Deficiency symptoms

• Depression
• Dermatitis
• Fatigue
• Insomnia
• Irritability
• Loss of appetite
• Muscle weakness
• Red, swollen tongue

Low levels of several B vitamins have been found in psychiatric patients and in senile dementia.

Preventing deficiency

See Vitamin B1. Alcohol severely inhibits vitamin B3 bioavailability. In many grains (particularly wheat and corn), vitamin B3 occurs in the form of a complex which cannot be digested or absorbed if the grain is unprocessed. Wheat requires baking with alkaline baking powder, and corn requires soaking in alkaline lime water before vitamin B3 is released.

Comments

See Vitamin B1. Some cases of severe vitamin B3 deficiency are indistinguishable from schizophrenia, and Dr Abram Hoffer in Canada has pioneered the treatment of schizophrenia using vitamin B3 megadoses, with many successes. Experiences of World War II ex-POWs from Japanese camps suggest that the longer and more severe a B3 deficiency, the higher the corrective dosages needed to restore normal function. Some schizophrenics may need more than 600 mg B3 per day, but this should be under the care of a specialist practitioner.

Oestrogens reduce the rate of conversion of tryptophan to vitamin B3, which means that when this vitamin is lacking, women in their child-bearing years are twice as likely as men to develop deficiency-related problems. Two enzymes required for the conversion are dependent on vitamins B2 and B6, so that deficiencies of either of these vitamins could also lead to vitamin B3 deficiency.

Vitamin B3 is also supplemented in large doses by many people for a cholesterol-lowering effect. However this approach does not address the possible causes of the high cholesterol, and holistic practitioners generally prefer to investigate these first.

SUPPLEMENTATION

In research studies, Vitamin B3 supplements have been found to:

• Act as a mild antihistamine
• Help relieve tinnitus
• Reduce cholesterol levels
• Reduce insulin requirements in some diabetics
• Reduce period (menstrual) pains
• Reduce the symptoms of schizophrenia when used in megadoses
• Reduce wheezing in asthmatics

Preferred form and suggested intake

See Vitamin B1. Vitamin B3 is available in two forms: the acid form (niacin, also known as nicotinic acid) and the amide form (niacinamide, also known as nicotinamide). The term niacin is often used as an umbrella for both forms. In most cases the preferred form for supplementation is the amide form. The acid form can produce an unpleasant 'flushing' effect as it causes the release of histamine.

Cautions

Doses of more than 500 mg vitamin B3, especially in timed-release form, have been linked with a few cases of liver damage.