Niacin
(Vitamin B3)

Traditionally Niacin was used as a generic term for a group of vitamin compounds (nicotinic acid and nicotinamide) that help to prevent pellagra (a niacin deficient disease), however more recently niacin has been shown to be an important cofactor in many energy transfer reactions assisting in energy production, fat and carbohydrate metabolism and several other metabolic processes.

The roles of niacin and riboflavin in cell metabolism are closely related and deficiency in both vitamins is regularly seen in the same individual. A deficiency in Vitamin B6 can also lead to a niacin deficiency as vitamin B6 assists in the synthesis of niacin from tryptophan, an amino acid found in animal and vegetable proteins.

The adverse health effects of a deficiency in niacin ranges from mouth sores and diarrhoea which can occur as a result of a mild deficiency, to the development of pellagra in a more severe cases. Pellagra is a disease that is characterised by the 3 D's; diarrhoea, dementia and dermatitis, however in severe cases it can also cause death.

The richest sources of niacin are liver and kidney, however smaller concentrations of niacin are also found in other red meats, poultry, fish, yeast, peanuts, bran and wholemeal wheat.

There is growing evidence that a diet supplemented with niacin well above the recommended dietary levels has a beneficial role in managing cholesterol and reducing the risk of cardiovascular disease, however such high doses also have adverse side effects and should only be done only under the advice and supervision of a doctor. Other recent studies have also suggested that niacin plays an important role in enhancing the sensitivity to insulin which may assist in the management of insulin resistant disorders such as type 2 diabetes.

Possible Additional Benefits of Niacin³:

• Possible cancer inhibitor.
• Large doses well above the RDI (ie 100-200 x RDI) have pharmacological effects such as improving blood cholesterol levels may reduce the risk of cardiovascular disease.

Recommended Dietary Intake for Niacin

Please refer to the following definitions when interpreting these recommendations:

RDI-Recommended Daily Intake
The average daily intake level that is sufficient to meet the nutritional requirements of nearly all (97-98%) health individuals in a particular life stage and gender group.

AI-Adequate Intake (used when an RDI cannot be determined)
The average daily nutrient intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate.

UL-Upper Limit of Intake
The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases.

RECOMMENDATIONS BY LIFE STAGE AND GENDER - Niacin

* Not possible to establish, source of intake from breast milk, formula or food only
** Not possible to determine, source of intake should be from food only

Source: National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Department of Health and Ageing, Canberra 2006, copyright Commonwealth of Australia reproduced by permission.

Niacin back to Vitamins

References:
1. Mann, J., Truswell, S. Essentials of Human Nutrition. Oxford Medical Publications, New York 2000.
2. MacWilliam, L.D. Comparative Guide to Nutritional Supplements. Northern Dimensions Publishing 2005.
3. Wahlqvist, M.L., et al. Australia and New Zealand: Food and Nutrition. 2nd Ed. Allen and Unwin, Sydney 2002.
4. The Merck Manual of Medical Information 2nd Ed. Beers, M.H., Fletcher, A. J., Jones T. J., Porter, R., Berkwits, M., et al., editors. Pocket Books Reference 2003.
5. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Department of Health and Ageing, Canberra 2006, copyright Commonwealth of Australia reproduced by permission.

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