Assessment of Iron Intake in Relation to Tolerable Upper Intake Levels

ABSTRACT

The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has, at the request of the Norwegian Food Safety Authority (Mattilsynet; NFSA), assessed the intake of iron in the Norwegian population in relation to tolerable upper intake levels (ULs). The existing maximum limit for iron in food supplements is 27 mg/day. VKM has also conducted scenario calculations to illustrate the consequences of amending the maximum limit to 5, 10, 20, 30, 40 or 50 mg/day. Iron deficiency is one of the most common nutritional disorders in the world. Individuals with increased iron demand such as growing children and pregnant women, those who experience blood loss such as menstruating women are particularly at risk for the consequences or iron deficiency. Iron deficiency can lead to fatigue and anaemia. The most common adverse effects of iron supplementation are reversible gastrointestinal symptoms. Chronic iron excess can lead to iron overload which is associated with several irreversible severe health outcomes such as cancers and cardiovascular diseases. Up to 1% of the population have a genetic trait that leads to accumulation of iron and renders them more vulnerable to iron excess. An adult needs approximately 10 mg iron per day to overcome daily loss. The tolerable upper intake level (UL) for iron in adults range from 45 to 60 mg/day. However, all previous reports acknowledge the challenges in defining upper levels. The Expert Group on Vitamins and minerals (EVM), UK report provided a guidance level (GL) of 17 instead of a UL and the Nordic Nutrition Recommendations (NNR) (2012) suggested an UL of 60 mg/day, but did not suggest any clear upper levels for children. Institute of Medicine (IOM), US (2001) gives the most substantiated tolerable upper intake levels based on gastrointestinal effects, which is 40 mg/day for infants and children, regardless of age, and 45 mg/day for adolescents and adults. The Joint FAO/WHO Expert Committee on Food Additives 2003 (JECFA) also took the potential serious effects of iron overload into account and suggested a GL of 50 mg/day in adults or 0.8 mg/kg per day in children and adolescents. Because the risks and consequences from overload are significant and potentially serious, VKM suggests that the GL from JECFA (2003) is used. Using the GL from JECFA (2003), none of the suggested doses can be given to 2 or 4-yearold children, 9 year olds can add 5 mg iron from supplements, 13 year olds 20, and adults 30 mg without exceeding the guidance levels.