Best time to take iron
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Optimal Timing for Iron Supplementation: Morning vs. Afternoon
Morning Iron Supplementation: Enhanced Absorption
Research consistently indicates that taking iron supplements in the morning can significantly enhance iron absorption. A study involving iron-depleted women demonstrated that consuming iron in the morning, especially with ascorbic acid (vitamin C), increased fractional iron absorption (FIA) by 30% compared to taking it with water alone . This effect was not further enhanced by higher doses of ascorbic acid, but it was notably reduced when iron was taken with coffee or breakfast . Additionally, serum hepcidin levels, which inhibit iron absorption, were found to be lower in the morning, further supporting the efficacy of morning supplementation .
Impact of Exercise on Iron Absorption
For athletes, the timing of iron supplementation relative to exercise also plays a crucial role. A study on endurance-trained runners found that iron absorption was significantly higher when supplements were taken in the morning post-exercise compared to the afternoon . This suggests that the post-exercise window in the morning may provide a transient mechanism that promotes iron absorption, counteracting the inhibitory effects of elevated hepcidin levels .
Alternate-Day Dosing: A Superior Strategy
Recent studies have also explored the frequency of iron supplementation. It has been shown that taking iron supplements on alternate days rather than consecutive days can optimize iron absorption. This regimen prevents the persistent elevation of hepcidin levels, which can inhibit iron absorption 45. For instance, a study comparing consecutive and alternate-day dosing found that alternate-day dosing resulted in higher cumulative fractional iron absorption and lower serum hepcidin levels .
Evening Supplementation: Comparable Efficacy
Interestingly, some research suggests that evening supplementation may be just as effective as morning supplementation. A study on ballet and contemporary dancers found no significant difference in the increase of serum ferritin levels between those who took iron in the morning and those who took it in the evening over an eight-week period . This indicates that while morning supplementation may have certain advantages, evening supplementation can still be effective, particularly for individuals who may experience gastrointestinal discomfort from morning doses.
Conclusion
In summary, the optimal time to take iron supplements appears to be in the morning, especially when combined with ascorbic acid and away from meals or coffee, to maximize absorption. For athletes, taking iron post-morning exercise can further enhance absorption. Additionally, adopting an alternate-day dosing schedule can improve iron absorption and reduce side effects. However, evening supplementation remains a viable option for those who may prefer it or experience discomfort with morning doses.
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