Iron Supplementation Is Associated With Aerobic Performance In Iron-deficient Female Soldiers

Abstract

Iron deficiency is associated with reduced aerobic performance, and may impair the adaptive response to aerobic training. Furthermore, diminished iron status observed during basic combat training (BCT) is associated with reduced aerobic performance in female Soldiers. The effect of iron supplementation on aerobic performance during BCT is unknown. PURPOSE: To determine the impact of iron supplementation during BCT on aerobic performance in female Soldiers. METHODS: Utilizing a randomized, double-blind, placebo-controlled design, female Soldiers (n = 153) were provided with pills containing either 100 mg ferrous sulfate (IRON) or placebo (PLACEBO) daily during a 9-week BCT course. Iron status indicators including red cell distribution width (RDW), serum ferritin (SF), and transferrin saturation (TS) were measured immediately prior to and following BCT. Iron deficiency was defined as presentation with two or more of the following: RDW > 15.0%, TS < 16.0%, SF < 12.0 ng·mL-1. Two-mile run time (RT) was assessed following BCT. Student's t-tests were used to compare RT between groups. RESULTS: Fifty-seven (37%) Soldiers began BCT iron deficient. Within this cohort, IRON-treated Soldiers demonstrated faster RT following training than those receiving PLACEBO ([mean ± SD]; 1068 ± 100 sec vs. 1154 ± 100 sec, p < 0.01). No between groups differences for RT were observed in Soldiers beginning BCT with normal iron status (1086 ± 87 sec vs. 1057 ± 72 sec, p > 0.05) or overall (1080 ± 92 sec vs. 1095 ± 98 sec, p > 0.05). CONCLUSIONS: These data suggest that daily iron supplementation (16 mg·day-1 elemental iron) may benefit aerobic performance in iron-deficient Soldiers. Future studies should focus on optimizing diet for preventing and treating iron deficiency in female Soldiers during military training. Research funded by MRMC.