The Norwegian Scientific Committee for Food Safety proposes that 10 mg nicotinic acid and 900 mg nicotinamide per day is used as tolerable upper intake levels for adults in Norway.
The proposal corresponds with the tolerable upper intake levels set by the former Scientific Committee for Food in EU in 2002. VKM has not considered recent literature, as it was not included in the terms of reference from the Norwegian Food Safety Authority.
The background for this assessment is that the Norwegian Food Safety Authority will establish new maximum limits for niacin in food supplements. The two main forms of niacin - vitamin B3 - are nicotinic acid and nicotinamide.
The intake of nicotinic acid and nicotinamide from the diet is considered to be without risks of adverse health effects. The proposed tolerable upper intake levels therefore apply only to the intake of nicotinic acid and nicotinamide from food supplements.
Adverse effects from high intakes
Severe niacin deficiency, pellagra, may cause symptoms such as fatigue, headache, apathy, increased pigmentation in the skin after exposure to sunlight, vomiting and diarrhoea.
A moderately high intake of nicotinic acid from food supplements, i.e. more than 35 mg per day, may cause side effects such as redness, burning itching on the face, arms and chest and stomach irritation. Very high doses of nicotinic acid, i.e. 3000 mg per day or more over a long period of time, for example in subjects taking cholesterol-lowering drugs, may at worst lead to liver failure.
It is not shown that intake of nicotinamide causes such side effects. Generally, nicotinamide is considered to have low toxicity.
The assessment is conducted by the Panel on Nutrition, Dietetic Products, Novel Food and Allergy.