Niacin (B3)

Like some other B vitamins, niacin is needed to convert food into energy. It’s a water-soluble vitamin and should be eaten every day.

Where can I get it?

Niacin is an unusual vitamin because your body can make a certain amount itself, from an amino acid called tryptophan (found in foods containing protein).

In this country most people eat a lot of protein, which provides enough tryptophan to convert to niacin. Some foods contain tryptophan as well as niacin – peanuts are a good source of both.

If low amounts of niacin and tryptophan are eaten in the diet there’s a risk of niacin deficiency (called ‘pellagra’). Although unusual in this country in otherwise healthy people, it’s sometimes seen in people with a very low overall food intake.

Pellagra causes rough skin and a sore, swollen tongue, digestion problems and diarrhoea and, in very advanced cases, it can cause headaches, confusion and dementia - even death, if it’s not treated.

Good sources of niacin or tryptophan (sometimes called ‘niacin equivalents’) include meat, fish, peanuts and fortified cereals. Milk and dairy products, vegetables and coffee also provide niacin.

How much should I eat?

It’s recommended that men consume 17mg a day and women consume 13mg a day. You’ll easily get all you need from a varied, balanced diet.

Supplements aren’t advised because it’s not fully understood what the effects may be, although some research suggests it may be harmful if very high amounts are taken over a long period.

A small bag of plain peanuts and raisins provides around
5 ½ mg; a portion (140g) of grilled mackerel has around 18mg.

What does it do?

Niacin helps to convert the food you eat into energy and it also helps to keep the nervous system and digestive system healthy.

Although the B vitamins contribute to similar systems, one vitamin can't replace another – the systems are extremely complex and there are lots of separate stages. A particular vitamin may help complete just one stage of a whole process.