The Norwegian Scientific Committee for Food Safety (VKM) has, at the request of the Norwegian Food Safety Authority (NFSA), assessed the risk associated with magnesium in food supplements. VKM has evaluated upper tolerable intake levels for magnesium and high and low intakes in the Norwegian population.
Pending establishment of common maximum limits in the EU, the NFSA is evaluating the national maximum limits for vitamins and minerals in food supplements. This risk assessment is the scientific basis for NFSA's evaluation of national limits for magnesium.
Magnesium salts in food supplements may cause osmotic diarrhoea which is the most frequently reported adverse effect. However, these effects are considered relatively mild. No tolerable upper intake level (UL) has been established for magnesium intake from food sources for the reason that no adverse effects have been recognised in healthy populations.
The tolerable upper intake level varies between countries. In 1997 the Institute of Medicine suggested that the upper intake level for magnesium in food supplements in adults to be 350 mg/day.
VKM found no results to support an alteration of this UL. VKM therefore suggests a UL of 350 mg magnesium in food supplements per day in adults which is in accordance with the UL suggested by (IOM, 1997). This UL will also cover the recommended intakes for the adult population.
Children 1-3 years
Children 3-10 years
Children (10-<14 years)
Adolescents (14-<18 years)
Adults (≥18 years)
According to the habitual dietary intakes of magnesium estimated from nationwide dietary surveys in Norway, about 25 percent of adults have intakes of magnesium below the recommendations from food and supplements. Almost the same percentage was below the recommended intakes among 9-year-old children, while approximately 70 percent of 13-year-olds had an intake of magnesium below the recommendations.
It should be noted that the intakes have been estimated with use of different dietary survey methods for the different age categories and a comparison of estimates across age groups can be misleading and has a high degree of uncertainty.
The VKM Panel on Nutrition, Dietetic Products, Novel Food and Allergy has been responsible for the risk assessment.