Best time to take iron supplements
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Optimal Timing for Iron Supplementation: Insights from Recent Research
Morning Iron Supplementation for Enhanced Absorption
Research consistently indicates that taking iron supplements in the morning can significantly enhance iron absorption. A study involving iron-depleted women found that consuming iron supplements in the morning, away from meals and coffee, and with an ascorbic acid (AA)-rich beverage, such as orange juice, maximizes iron absorption. The study showed that 80 mg of AA increased fractional iron absorption (FIA) by 30%, while coffee reduced FIA by 54%. Additionally, serum hepcidin levels, which inhibit iron absorption, were higher in the afternoon, leading to a 37% reduction in FIA compared to morning intake.
Alternate-Day Dosing to Maximize Iron Absorption
Recent studies suggest that alternate-day dosing of iron supplements may be more effective than daily dosing. This regimen helps to avoid the acute increase in serum hepcidin that follows iron intake, which can persist for 24 hours and reduce iron absorption from subsequent doses. Research indicates that providing iron supplements on alternate days results in higher cumulative fractional iron absorption compared to consecutive-day dosing . For instance, one study found that alternate-day dosing led to a 40-50% higher FIA compared to consecutive-day dosing.
Single Morning Doses vs. Split Doses
Studies comparing single morning doses to twice-daily split doses have shown that single morning doses are preferable. Split dosing increases serum hepcidin levels more than single doses, thereby reducing iron absorption. One study found no significant difference in total iron absorption between once-daily and twice-daily dosing, but twice-daily dosing resulted in higher serum hepcidin concentrations. Therefore, single morning doses are recommended to optimize iron absorption and minimize side effects .
Impact of Timing on Iron Supplementation Efficacy
While morning supplementation is generally recommended, some studies have explored the efficacy of evening supplementation. A study on ballet and contemporary dancers found no significant difference in serum ferritin levels between those who took iron supplements in the morning and those who took them in the evening over an 8-week period. This suggests that while morning supplementation may be optimal for maximizing absorption, evening supplementation can still be effective in increasing iron stores.
Conclusion
To optimize iron absorption, it is best to take iron supplements in the morning, away from meals and coffee, and with an ascorbic acid-rich beverage. Alternate-day dosing is recommended over daily dosing to avoid the inhibitory effects of increased serum hepcidin. Single morning doses are preferable to split doses to maximize absorption and minimize side effects. While evening supplementation can still be effective, morning intake remains the optimal strategy for enhancing iron absorption and improving iron status.
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