Daily iron supplementation significantly improves maximal and submaximal exercise performance in WRA , providing a rationale to prevent and treat iron deficiency in this group .
Animal and human observational studies suggest that iron deficiency impairs physical exercise performance , but findings from r and omized trials on the effects of iron are equivocal .
Iron deficiency and anemia are especially common in women of reproductive age ( WRA ) .
Clear evidence of benefit from iron supplementation would inform clinical and public health guidelines .
Therefore , we performed a systematic review and meta- analysis to determine the effect of iron supplementation compared with control on exercise performance in WRA .
Marginal iron deficiency without anemia impairs aerobic adaptation among previously untrained women.
BACKGROUND Iron deficiency without anemia has been shown to reduce both muscle-tissue oxidative capacity and endurance in animals . However , the consequences of iron deficiency in humans remain unclear . OBJECTIVE We investigated the effects of iron supplementation on adaptation to aerobic training among marginally iron-depleted women . We hypothesized that iron supplementation for 6 wk would significantly improve iron status and maximal oxygen uptake ( VO(2)max ) after 4 wk of concurrent aerobic training . DESIGN Forty-one untrained , iron-depleted , nonanemic women were r and omly assigned to receive either 50 mg FeSO(4 ) or a placebo twice daily for 6 wk in a double-blind trial . All subjects trained on cycle ergometers 5 d/wk for 4 wk , beginning on week 3 of the study . RESULTS Six weeks of iron supplementation significantly improved serum ferritin and serum transferrin receptor ( sTfR ) concentrations and transferrin saturation without affecting hemoglobin concentrations or hematocrit . Average VO(2)max and maximal respiratory exchange ratio improved in both the placebo and iron groups after training ; however , the iron group experienced significantly greater improvements in VO(2)max . Both iron-status and fitness outcomes were analyzed after stratifying by baseline sTfR concentration ( > and < or = 8.0 mg/L ) , which showed that the previously observed treatment effects were due to iron-status and fitness improvements among subjects with poor baseline iron status . CONCLUSIONS Our findings strongly suggest that iron deficiency without anemia but with elevated sTfR status impairs aerobic adaptation among previously untrained women and that this can be corrected with iron supplementation
Daily iron supplementation significantly improves maximal and submaximal exercise performance in WRA , providing a rationale to prevent and treat iron deficiency in this group .
Animal and human observational studies suggest that iron deficiency impairs physical exercise performance , but findings from r and omized trials on the effects of iron are equivocal .
Iron deficiency and anemia are especially common in women of reproductive age ( WRA ) .
Clear evidence of benefit from iron supplementation would inform clinical and public health guidelines .
Therefore , we performed a systematic review and meta- analysis to determine the effect of iron supplementation compared with control on exercise performance in WRA .