Quantitative relations between baseline iron status , study duration , and iron dose on changes in iron-status biomarkers , which were generated from the meta-analyses , can be used to predict effects of trials of iron supplementation and fortification and to design iron-intervention programs
BACKGROUND The response of status biomarkers to an increase in iron supply depends on several physiologic and environmental factors , which make it difficult to predict the outcome of an intervention .
OBJECTIVE We assessed effects of baseline iron status , sex , menopausal status , duration of intervention , iron form , and daily dose on the change in iron status in response to iron supplementation .
Iron supplementation maintains ventilatory threshold and improves energetic efficiency in iron-deficient nonanemic athletes
Objective : To determine the effect of iron supplementation on iron status and endurance capacity . Design : R and omized , double-blind iron supplementation . Setting : University of Missouri-Columbia and surrounding community . Subjects : Twenty iron-deficient ( serum ferritin , sFer<16 μg/l ; serum transferrin receptor , sTfR>8.0 mg/l ; or sTfR/log sFer index > 4.5 ) , nonanemic ( hemoglobin , Hb>120 g/l , women ; > 130 g/l , men ) men and women ( 18–41 years ) were recruited via fliers and newspaper advertisements ; 20 of 31 eligible subjects participated . Interventions : A 30 mg measure of elemental iron as ferrous sulfate or placebo daily for 6 weeks . Results : Dietary iron intake and physical activity did not differ between groups before or after supplementation . Iron supplementation significantly increased sFer compared to placebo ( P=0.01 ) , but did not affect Hb or hematocrit . Iron supplementation prevented the decline in ventilatory threshold ( VT ) observed in the placebo group from pre- to post-supplementation ( P=0.01 ) ; this effect was greater in individuals with lower sFer before intervention ( P<0.05 ) . Changes in sFer from pre- to post-treatment were positively correlated with changes in VT ( P=0.03 ) , independent of supplementation . The iron group significantly increased gross energetic efficiency during the submaximal test ( P=0.04 ) . Changes in sFer were negatively correlated with changes in average respiratory exchange ratio during the submaximal test ( P<0.05 ) . Conclusions : Iron supplementation significantly improves iron status and endurance capacity in iron-deficient , nonanemic trained male and female subjects . Sponsorship : Missouri University Alumni Association , by the Elizabeth Hegarty Foundation and by the Department of Nutritional Sciences
Quantitative relations between baseline iron status , study duration , and iron dose on changes in iron-status biomarkers , which were generated from the meta-analyses , can be used to predict effects of trials of iron supplementation and fortification and to design iron-intervention programs
BACKGROUND The response of status biomarkers to an increase in iron supply depends on several physiologic and environmental factors , which make it difficult to predict the outcome of an intervention .
OBJECTIVE We assessed effects of baseline iron status , sex , menopausal status , duration of intervention , iron form , and daily dose on the change in iron status in response to iron supplementation .