What Is the Scientific Evidence for Iron?
A double-blind, placebo-controlled trial of 42 non-anemic women with evidence of slightly low iron reserves found that iron supplements significantly enhanced sports performance . 36 Participants were put on a daily aerobic training program for the latter 4 weeks of this 6-week trial. At the end of the trial, those receiving iron showed significantly greater gains in speed and endurance as compared to those given placebo. In addition, a double-blind, placebo-controlled study of 40 non-anemic elite athletes with mildly low iron stores found that 12 weeks of iron supplementation enhanced aerobic performance. 37 Benefits with iron supplementation were observed in other double-blind trials as well also involving mild low iron stores. 51,52 However, other studies failed to find significant improvements, 53-55 suggesting that the benefits of iron supplements for non-anemic, iron-deficient athletes is small at most.
