1. Individuals possessing the medium or high risk HFE genotypes outperformed those with lower risk genotypes in a 10km cycling time trial.
2. Individuals in the medium or high risk HFE genotypes possessed a greater VO2peak compared with those with a lower risk genotype.
Evidence Rating Level: 2 (Good)
Mutations in the human homeostatic iron regulator (HFE) gene can lead to excessive amounts of iron in the bloodstream. At toxic levels, this may cause hemochromatosis; however, if below this threshold, higher iron content may result in enhanced endurance capacity due to the increased production of red blood cells. The purpose of this study was to determine whether certain HFE genotypes were associated with enhanced endurance performance [lower 10km cycling time trial or an increase in maximal oxygen uptake (VO2peak )]. This retrospective cohort study recruited 100 competitive male athletes from a variety of sports backgrounds. Participants in this study were included if they had various HFE risk genotypes and were training and/or competing for ≥8hrs week for 9 out of 12 months out of the year for at least 3 years. For the assessment, athletes completed a 10km cycling time trial as well as a VO2peak test on four different occasions, 1 week apart.
The results of this study demonstrated that high risk HFE genotypes were associated with greater endurance performance in the 10km cycling time trial compared to lower risk HFE genotypes. Similarly, athletes with high risk HFE risk genotypes tended to have a higher VO2peak . The study’s greatest strength was the protocol, which instructed athletes to maintain regular sleeping and eating habits, as well as repeat testing which helped increase the strength of the association. However, the very selective sample size of elite male athletes limited the generalizability of the results. Nonetheless, the study’s findings suggest the importance of monitoring and optimizing an athlete’s iron status through supplementation under the guidance of health professionals, as the latter could have a significant impact on endurance performance.
Click to read the study in Medicine & Science in Sports & Exercise
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