Nicotinic acid, niacin and niacinamide are names for the vitamin substance B3. Vitamin B3 is reference for two forms:
- The acid form (nicotinic acid)
- The amide form (nicotinamide)
Niacin is an American name synonymous with nicotinic acid and niacinamide is an American name synonymous with nicotinamide. All forms are referred to as vitamin B3, which is a member of the
B complex group of water-soluble vitamins. The two forms have very different characteristics.
Nicotinic acid has a vasodilatory action and is concerned with:
- blood circulation
- the reduction of cholesterol and fats
- maintaining health of digestive organs and nervous system
- general health of the brain, skin and tongue.
- It is also a precursor to the amide form.
Nicotinamide is concerned with:
- the breakdown of carbohydrates, fats and protein
- energy production
While nicotinic acid is converted to the amide form nicotinamide, the reverse is not true. Therefore, in certain uses like reducing blood fats and cholesterol or in circulatory vasodilatory conditions, only the acid form is beneficial. The amide form would be non-effective in these cases.
In this text niacin is used as the name for B3 except where the acid or the amide form needs to be specified.
Niacin is known as an energy vitamin and is more stable than the other two energy vitamins, thiamin and riboflavin. These three nutrients are related since they all belong to the B complex group and share the same function – that of converting food to energy.
B3 was first discovered because of the serious disease called pellagra, which was rife in the early part of the 20th century, particularly in the southern states of America. It is still widespread in many other parts of the world where diet is poor, which shows how important diet is to health.
Nicotinic acid is made in the body from the amino acid L-tryptophan, although the little that is produced in this way is insufficient to prevent a deficiency occurring. For this reason, nicotinic acid can be officially termed a vitamin because it fulfils the following criteria: – it can be made in body tissue but not in quantities to prevent deficiency and so must be provided in the diet from food.
Deficiency of niacin will produce clinical symptoms. Symptoms and signs of deficiency can be cured or reversed by administering the appropriate vitamin.
Foods that contain the highest levels of nicotinic acid are yeast extract and dried brewer’s yeast. Other foods that contain substantial amounts are:
- liver, kidney, beef, lamb, pork and chicken
- fish (white fleshed and oily)
- dairy produce: eggs, milk, cheese and yoghurt
- wholemeal bread, wheat bran and wheatgerm,
- oat flakes, maize and rice
- citrus fruits, dried fruits, bananas and nuts
- potatoes, root vegetables, green leafy vegetables and pulses
- Instant coffee, whether it is decaffeinated or not, contains nicotinic acid but should not be considered a significant source.
Vitamin B3 is a stable vitamin and is lost primarily because of its water solubility. Water used in boiling, poaching or braising should be used to make gravy or sauce so that some of the nutrient in the water will be retained.
Processing and refining also reduces the potency of vitamin B3 to some extent. Excessive consumption of simple carbohydrates (foods high in sugar and refined flour) can deplete the body’s reserves of niacin. Drugs used to treat leukaemia also have an adverse effect on vitamin B3.
Additional intake may be required by alcoholics, those with tobacco addiction, arthritics, and people with high blood cholesterol or with a family history of atherosclerosis.
Severe signs of deficiency are the symptoms of pellagra which include dry, cracked, scaly skin that becomes red and inflamed and diarrhoea, mental confusion, memory loss and nervous tension. The name of the disease ‘pellagra’ means ‘rough skin’ in Italian and that is the common first symptom of deficiency.
Other symptoms can include insomnia, irritability, stress and depression, all of which are related to the nervous system. Intestinal upsets, nausea, vomiting and inflammation of the mouth may also occur.
B3 (Niacin) works synergistically with other B complex nutrients and should be taken with other members of the group unless it is being taken for specific therapeutic purposes.
Thiamin (B1) and pyridoxine (B6) are particularly important to B3 in the body in connection with nervous problems. Both of these vitamins are involved in the conversion of L-tryptophan to nicotinic acid.