Vitamin B3 (niacin)

Men need around 17 milligrams a day and women, around 13 milligrams of vitamin B3 (niacin) per day.

The 2014 UK National Diet and Nutrition Survey found that for vitamin B3 (niacin), average daily intakes from food were well above the recommended level for most people with less than 0.5 per cent failing to meet targets. Cereals and cereal products were the largest contributor of niacin for younger children.

Vitamin B3 (niacin) helps to release energy from the foods we eat, it is essential for many basic reactions in the body and helps to maintain the nervous system and keep skin healthy.

There are two forms of niacin: nicotinic acid and nicotinamide, both of which are found in food. The amino acid tryptophan (a component of some proteins) is also converted by our bodies to nicotinamide.

Taking high doses of nicotinic acid supplements (over 200 milligrams daily) can cause skin flushes and taking extremely high doses (3-6 grams daily) can be toxic to the liver and lead to liver damage. In 2024, a study published in Nature Medicine suggested that people with higher levels of niacin in their blood may be more at risk of a heart attack or stroke, possibly because too much of the vitamin inflames blood vessels.

Government guidelines say that taking 17 milligrams or less of nicotinic acid supplements a day or 500 milligrams or less of nicotinamide supplements a day is unlikely to cause any harm.

No, a healthy vegan diet containing the foods below on a daily basis will cover your needs.

The best plant sources of vitamin B3 (niacin) include nutritional yeast, peanuts, fortified vegan breakfast cereals, quinoa, muesli, yeast extract (Marmite/Vegemite), wild rice, wholemeal spaghetti, corn on the cob, brown rice and acorn squash.

Nutritional yeast is a food additive that can be used as a condiment or ingredient. It is made from yeast grown on molasses and then harvested, washed and heated to kill or ‘deactivate’ it. It doesn’t froth or grow like baking yeast as it is inactive. It is sold in tubs of flakes that can be sprinkled on dishes or added to sauces. Very popular with vegans, it even has its own nickname – nooch! A 5g teaspoon of nutritional yeast provides 100-130 per cent of your daily requirement of niacin. Buy one that’s fortified with vitamin B12 to cover all bases!

You should be able to get all the niacin you need from your daily diet but it can’t be stored in the body, so you need it in your diet every day.

Skin lesions on skin exposed to sunlight and/or pressure, diarrhoea, in extreme cases also loss of mental capacity. The disease caused by severe niacin deficiency and characterises by these symptoms is called pellagra.

Source: Public Health England: McCance and Widdowson’s The Composition of Foods Integrated Dataset, *Engevita, Marigold Health Foods Ltd.

Some news reports suggested that niacin supplements might help reduce miscarriages and/or genetic abnormalities in infants. However, it is very early days for this research and more research will need to be done before making any firm recommendations for niacin.

The government do recommend that all women who are considering pregnancy take a 400 micrograms of folic acid tablet every day until the 12th week of pregnancy. This is one of the most important vitamins for pregnancy. It’s also a good idea to eat more foods containing folate, such as green leafy vegetables, fortified breakfast cereals, soya foods (tempeh, tofu and soya milk). For an extra boost include some yeast extract (Marmite) and nutritional yeast. They also recommend that pregnant women and women who are breastfeeding all take vitamin D supplements of 10 micrograms a day.

The National Institute for Health and Care Excellence (Nice) says that there is no evidence that anything other than folic acid and vitamin D are needed as supplements in pregnancy. The use of multi-vitamin supplements is not recommended as these often contain vitamin A which can cause birth defects.