Relationships between changes in iron status and maximal oxygen uptake (VO2 max) after a 5 month iron‐biofortified bean efficacy trial (646.3)

Abstract

Objective: To examine the effects of an iron‐biofortified bean intervention on physical performance in Rwandan women assessed by VO2max.Methods: 145 Rwandan women (18‐26 years) were randomized to receive either iron‐biofortified beans or traditional beans twice daily for 5 months. Blood biomarkers and VO2max were measured before and after the feeding period. VO2max was assessed with a mechanically braked cycle ergometer (Monark 874E). Heart rate, VO2, and VCO2 were directly measured with the Cosmed K4B2 system. Non parametric tests and general linear models were used to evaluate the effect of the intervention on blood biomarkers and VO2max.Results: Serum ferritin significantly increased in the iron‐biofortified group (4.0 μg/l increase in median in treatment group, 2.5 μg/l increase in median in control group; p=0.04). VO2max declined in both groups over the course of the intervention with no difference between the high iron and control beans. However, in iron status responders (those with ferritin increase of 15% or more; n=122), women in the treatment group had significantly attenuated decline in VO2max compared with women in the control group (estimate 2.11 ml O2/min/kg, p=0.02).Conclusion: Consumption of iron‐biofortified beans significantly improved iron status in Rwandan women, and improvements in iron status in the iron‐biofortified group attenuated the decline in VO2max.Grant Funding Source: Supported by HarvestPlus