What is niacin (vitamin B3)?

Written by Catherine Saxelby on Wednesday, 18 February 2015.
Tagged: health, healthy eating, nutrition, vitamins

What is niacin (vitamin B3)?
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Niacin is the common name for the two compounds, nicotinic acid and nicotinamide (or niacinamide) and is often referred to as vitamin B3. It is vital for your health and is one of the most commonly added “fortification vitamins” found in foods such as breakfast cereals and breads.

What does niacin do in the body?

Niacin is involved in many vital functions including:

  • the release of energy from food
  • the metabolism of carbohydrate, protein and fat
  • the repair of DNA and mobilization of calcium
  • helping the body’s cells absorb oxygen
  • interacting with enzymes to process the body’s fuel
  • being essential for growth.

How much niacin do I need?

Because of niacin’s role in energy metabolism, an individual’s niacin requirement is based on their overall energy requirements. As a rough guide, use the RDIs* below.


2 mg as preformed niacin found naturally in breast milk (0-6 months) AI**

4 mg (7-12 months) AI**


6 mg (1-3 yrs)

8 mg (4-8 yrs)

12 mg (9-13 yrs)

Older children

14 mg girls (14-18 yrs)

16 mg boys (14-18 yrs)


14 mg

18 mg during pregnancy

17 mg during lactation


16 mg

**AI means Adequate Intake (used when there are no RDIs)

* Recommended Dietary Intakes

mg means milligrams     Source: NRVs from NHMRC Australia and New Zealand 2006

Niacin can also be formed in the body from the amino acid tryptophan which can be found in animal proteins, seafood including prawns, sardines and salmon, as well as dairy foods like milk, cheese and yoghurt. The combination of preformed niacin and that contributed by tryptophan is measured as ‘niacin equivalents'.

What is the safe upper limit of niacin intake from all sources per day?

    (niacin as nicotinamide)


150 mg (1-3 yrs)

250 mg (4-8 yrs)

500 mg (9-13 yrs)

Older children

750 mg (14-18 yrs)

Adults (men and women*)

900 mg

*It is not possible to establish the safe level during pregnancy and lactation, but the source of intake should be from food only.

Safe upper limit of niacin intake from fortified foods or supplements per day

    (niacin as nicotinic acid)


10 mg (1-3 yrs)

15 mg (4-8 yrs)

20 mg (9-13 yrs)

Older children

30 mg (14-18 yrs)


35 mg

30 mg (14-18 yrs) during pregnancy and lactation

35 mg (19-50 yrs) during pregnancy and lactation


35 mg

Where to find niacin

Niacin is found in a number of foods, notably protein foods like meat, poultry and fish (particularly in organ meats or offal), legumes (especially peanuts), whole (unrefined) grains, nuts, seeds and in eggs and cow’s milk. The niacin in meats is more bioavailable than that in grains but for the non-meat eaters, legumes are a good source of niacin.

As a side note, if you have inadequate iron, riboflavin or vitamin B6 levels, niacin is less bioavailable altogether. Have a look at our posts on ironand riboflavin to see that you are eating enough of their rich food sources. 

Here’s a list of the Top 20 richest food sources of niacin, both natural and fortified:

  1. Hand holding Chicken drumstickYeast spread e.g. Vegemite, Marmite
  2. Unprocessed rice or wheat bran
  3. Breakfast cereal / biscuits fortified with niacin
  4. Beverage powder fortified with niacin e.g. Acktavite, Milo, Ovaltine
  5. Peanuts, raw or roasted
  6. Chicken breast
  7. Sunflower seeds
  8. Liver
  9. Yellowfin tuna steaks
  10. Veal cutlets
  11. Muesli, natural or toasted
  12. Anchovies, canned and drained
  13. Chilli powder
  14. Bacon, lean part (‘eye’)
  15. Sundried tomatoes
  16. Ham
  17. Tuna, canned and drained
  18. Cocoa powder
  19. Wheat germ
  20. Tahini (ground sesame seeds)

Easy ways get your recommended day's intake of 14 - 16mg niacin:

It’s relatively easy to get enough niacin as the vitamin is widely distributed in protein foods as well as being added to fortified cereals and breads – niacin is one of the four vitamins added to most fortified products. Look for the word ‘niacin’ under Vitamins on the Ingredient List on the food label.

Most breakfast cereals are fortified with niacin at the level of 25 per cent of the average adult’s RDI or 2.5mg per serve or bowl as well as with the other B vitamins like B1, B2 and folate.

Refined food such as sugar, oils and many processed foods have little or none.

Here are 6 easy ways to get enough niacin:

90g grilled chicken breast 15mg
150g grilled beef 14mg
75g canned tuna (10mg), 1 cup canned chick peas (2.5), ½ cup canned corn (1.5) 14mg
2 Tb peanut butter (11.4), 4 Vita-Weats (1.8), 1 fresh peach (1.8) 15mg
Bowl or 50g niacin-fortified breakfast cereal (11.5) with 1 Tbsp sunflower seeds (2.0) plus 200ml reduced fat milk (2.3) 16mg
250ml cappuccino with reduced fat milk (7.7), 1 slice wholegrain bread (1), 1 tsp Vegemite (8) 17mg

      Source: Foodworks and NUTTAB 2010 database

Deficiency signs of niacin

Niacin deficiency can cause fatigue, diarrhoea, dermatitis and in severe cases, mental disorders such as depression, delirium or dementia.

A deficiency of this vitamin causes a disease known as pellagra, which causes inflammation of the skin on exposure to sunlight. It was first seen in populations that had corn (maize) as their staple food because the form of niacin found in corn, unlike other cereals, is not well absorbed.

Treatment for high cholesterol

Niacin, as a high-dose supplement, has proven very effective at lowering high blood levels of LDL-cholesterol and triglycerides.

The dose used ranges from 1500 mg to 3000 mg a day as nicotinic acid, which is hundreds of times more than the recommended dietary intake from food.

This should only be taken under your doctor’s supervision as it has side effects such as flushing of the skin due to the dilating of blood vessels in the face not to mention itchy skin, rashes, upset stomach and headaches. If taken for too long, it can lead to gout and liver damage. 

Catherine Saxelby About the author

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