Vitamin B3

niacin

Vitamin B3 helps to break down protein,fat and carbohydrate into the simpler substances needed for the release of energy. It stimulates the circulation, reduces cholesterol levels, and helps in the creation if several hormones, includin8 cortisone and the sex hormones. As well as enhancing normal brain function, vitamin B3 keeps the skin and digestive tract healthy, and is thought to have a role in protecting against cancer.

Availability in food

Vitamin B3 is derived from two compounds: nicotinic acid and niacinamide. Both forms are easily absorbed from the small intestine and have broadly similar actions, although nicotinic acid, in high doses, appears to lower cholesterol.

Vitamin B3 is readily obtainable from nuts, pig's liver, soy flour, wheat, peanut butter and potatoes. There is little or no loss in cooking, but up to 90 per cent can be lost from whole grains when they are milled. Food manufacturers often add vitamin B3 to their products to replace this loss.

What if your intake is too low?

Even if the diet contains inadequate vitamin B3, deficiency is unlikely as B3 can be manufactured in the body, provided the diet is otherwise adequate. If the diet is extremely poor over a long period mental changes, such as irritability, loss of memory and confusion can occur. The skin develops an unpleasant, dry roughness, particularly on the areas exposed to the sun. The tongue becomes painful and cracked, and there are digestive upsets including diarrhoea and loss of appetite. These are the symptoms of pellagra, which can be fatal if left untreated.

When extra may be needed

  • If you regularly consume moderate or large amounts of alcohol
  • If you do not eat enough protein

(Pregnant and breastjeeding women should consult a doctor, midwife, or qualified nutritional therapist bifore taking any vitamin or mineral supplements.)

Can too much be toxic?

High doses of nicotinic acid (up to 6g a day) can reduce cholesterol levels and have also been used to clear the body of organic poisons, such as certain pesticides. However, since high doses can also cause liver damage, they should only be taken under medical supervision. Fortunately, the liver heals itself when the high intake of nicotinic acid is reduced.

If taken in excess of about 200mg, nicotinic acid, but not nicotinamide, dilates the blood vessels in the skin and produces flushing. It can also cause the blood pressure to drop. In younger people, a lower dose (50mg three times a day) to treat or prevent chilblains, can also cause a fall in blood pressure. To be safe, experts recommend that if you have any medical condition you should consult your doctor before taking vitamin B3 supplements in excess of 50mg per day.

Using a supplement

If you wish to take a supplement, vitamin B3 is best taken as part of a balanced B-vitamin table or capsule, unless your doctor or nutritional health practioner advises otherwise. If vitamin C is also present it helps to prevent vitamin B3 from being chemically degraded.

Producing your own vitamin B3

Ample vitamin B3 is available for those who eat animal protein as part of a well-balanced diet that contains adequate amounts of vitamin C, iron, and vitamins B1, B2 and B6. These nutrients are the raw materials that can be used by the body to make its own supply of vitamin B3 from an amino acid called tryptophan. This amino acid is abundantly present in both milk and eggs.

Vegans, however, have to take greater care to eat foods that contain sufficient vitamin B3, as plant proteins can be deficient in the amino acid tryptophan as well as being poor sources of vitamin B3. An example is sweetcorn (corn, maize). This grain is deficient in tryptophan and only contains a limited amount of vitamin B3 and that limited amount is in a form that cannot be used by the body without special treatment. Native American Indians knew that pre-treating sweetcorn (corn, maize) by soaking it in ash water prevented the onset of the disease that is now known as pellagra. However, poor white immigrants to the United States in the late nineteenth and early twentieth centuries did not know this and, since their diet consisted largely of untreated cornmeal, the immigrants developed pellagra. In fact, the resulting skin changes of early pellagra are what gave rise to the expression 'rednecks' which became a general term to describe these immigrant field workers.