Science - May 20, 2010

Marathon runners consume too much iron

Athletes often consume iron supplements because a lack of blood is bad for performance. Men in particular take in too much, rather than too little, according to research carried out by the Division of Human Nutrition.

Wageningen food researcher Michael Zimmermann and his Swiss colleague examined iron levels in the blood of 170 runners who participated in the Zurich marathon. They found that two of the 127 male marathon runners had low iron levels, compared with twelve out of 43 female runners. Five men and eleven women had iron deficiency. In contrast, nineteen men (fifteen percent) and two women (five percent) had excessive iron in their blood. An excess of iron is bad for the health in the long run. The researchers caution about the widespread use of iron supplements among athletes in this month's European Journal of Clinical Nutrition. They advise athletes to consume supplements only if the doctor has detected low iron levels or if they have anaemia.