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Why we need vitamin B3

Healthy woman holding dog

Niacin – or vitamin B3 – helps the body produce energy and is vital for the nervous system. It also keeps us functioning well psychologically and is great for our skin.

What happens if I don’t get enough vitamin B3?

In most developed countries, most people get plenty of vitamin B3. In fact, on average, we have just over twice as much as the recommended daily intake (RDI). It’s easy for us to meet and exceed the RDI because it’s found in a wide range of foods. It can also be made in the body from a protein building block called tryptophan (the amino acid also used to make mood-boosting serotonin). As the RDI is based on the amount we need to prevent a deficiency of that nutrient, there’s no need to worry if we get more of it through eating a healthy balanced diet.

New concerns

Nevertheless, there are fresh worries that pellagra – the disease caused by a deficiency of vitamin B3 – may be on the increase in Western countries, due to more people following fad diets or suffering from eating disorders. Early signs include loss of appetite, fatigue, stomach pain, vomiting and irritability. In the later stages, symptoms are often characterised by the three Ds: diarrhoea, dermatitis and dementia.

How much vitamin B3 do I need each day?

The Nutrient Reference Value (NRV) for vitamin B3, which you’ll see on food labels, is 16mg. But there are more detailed guidelines in the vitamin B3 needs at specific ages and stages in life such as in pregnancy and breastfeeding women.

Supplement safety

Niacin intakes from food don’t have any negative effects, but high doses from supplements can have a toxic effect, causing skin flushes and itching, nausea, gastric problems such as an upset stomach or diarrhoea and, in the long run, could lead to diabetes and liver damage. Look out for niacin on supplement labels in the form of nicotinamide or nicotinic acid: doses of below 500mg nicotinamide or 17mg nicotinic acid are unlikely to cause harm but remember, you’re probably getting more than enough niacin from food.

You may have read that nicotinic acid can help lower cholesterol. However, due to the side effects, it’s rarely prescribed. It certainly isn’t a substitute for cholesterol-lowering medication, so if you have high cholesterol, talk to your GP before taking any supplements containing niacin (especially in the form of nicotinic acid).

Everday foods for B3

FoodWeight in mg
1 (125g) grilled chicken breast27.5
140g grilled mackerel21.7
100g lamb's liver (raw weight)20.7
140g grilled salmon17.9
125g grilled rump steak17.3
125g can sardines in tomato sauce13.4
2 slices lean roast pork leg (80g)13.1
140g grilled haddock11.6
2 slices well-done lean roast beef (80g)11.1
100g lean minced beef (raw weight)9.4
200g cooked wholemeal pasta6
30g unsalted peanuts5.8
30g bran flakes5.4
150g cooked couscous5
150g cooked brown rice4.8
100g cottage cheese3.6
200g baked beans3.4
1 Weet-Bix/Weetabix/Wheat biscuit3.2
100g Quorn3
30g sunflower seeds2.7
1tbsp peanut butter2.6
1 slice wholemeal bread2.4
80g raw mushrooms2.4
30g reduced-fat cheddar2.3
1 egg2.1
80g frozen peas2
First published: Nov 2016