Iron supplementation in women
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Iron Supplementation in Women: Efficacy, Dosing, and Side Effects
Iron Deficiency and Anaemia in Women: Prevalence and Impact
Iron deficiency and iron deficiency anaemia (IDA) are widespread among women, especially those of reproductive age and during pregnancy. These conditions can lead to fatigue, reduced physical performance, and negative impacts on cognitive function and overall well-being Stoffel2020Low2016Pasricha2014+1 MORE.
Daily Iron Supplementation: Benefits and Drawbacks
Daily oral iron supplementation is effective in reducing the prevalence of anaemia and iron deficiency, raising haemoglobin levels, and improving iron stores in both menstruating and pregnant women Low2016Pasricha2014Peña-Rosas2009+1 MORE. It also improves physical exercise performance and reduces fatigue Low2016Pasricha2014Avery2020. However, daily supplementation is associated with increased gastrointestinal side effects such as constipation, diarrhoea, and abdominal pain, which can reduce adherence to treatment Low2016Peña-Rosas2009Peña-Rosas2015.
Intermittent Iron Supplementation: An Alternative Approach
Intermittent iron supplementation (one to three times per week) has been shown to be nearly as effective as daily supplementation in preventing and controlling anaemia and improving haemoglobin and ferritin levels in menstruating women Fernández-Gaxiola2019Fernández-Gaxiola2011. Intermittent regimens are associated with fewer side effects compared to daily dosing, making them a safer and more tolerable option for many women Fernández-Gaxiola2019Fernández-Gaxiola2011. In pregnant women, intermittent supplementation appears to be as effective as daily regimens for preventing anaemia, with a lower risk of side effects and haemoconcentration Peña-Rosas2009Banerjee2024.
Optimizing Iron Absorption: Dosing Strategies
Recent research suggests that the traditional approach of splitting high daily doses may not be optimal. Doses of 60–120 mg of elemental iron, given as a single morning dose on alternate days, maximize absorption and minimize side effects by allowing hepcidin levels (which inhibit iron absorption) to return to baseline between doses . This regimen may be particularly beneficial for women with iron deficiency or mild IDA .
Cognitive and Physical Performance Benefits
Iron supplementation in women with low iron status improves attention, memory, and subjective fatigue, with some evidence for benefits in mood and well-being Low2016Pasricha2014Avery2020. Improved iron status is also linked to better maximal and submaximal exercise performance, supporting the importance of supplementation for active women and those experiencing fatigue Low2016Pasricha2014Avery2020.
Iron Supplementation in Pregnancy: Safety and Outcomes
Routine iron supplementation during pregnancy reduces the risk of maternal anaemia and iron deficiency, and increases haemoglobin and ferritin levels Watt2024Peña-Rosas2009Peña-Rosas2015. There is no clear evidence that supplementation significantly affects birth weight, preterm birth, or neonatal outcomes, and the risk of adverse effects is generally low Watt2024Peña-Rosas2009Peña-Rosas2015. However, daily supplementation may increase the risk of haemoconcentration, the clinical significance of which remains uncertain Peña-Rosas2009Peña-Rosas2015.
Conclusion
Iron supplementation is a proven strategy to prevent and treat iron deficiency and anaemia in women, with clear benefits for haemoglobin levels, iron stores, physical performance, and fatigue. While daily supplementation is effective, intermittent or alternate-day regimens may offer similar benefits with fewer side effects, improving adherence and overall outcomes. For both menstruating and pregnant women, tailoring the dosing schedule and amount of iron can optimize absorption and minimize harm. Further research is needed to refine guidelines and address gaps in knowledge about long-term outcomes and optimal regimens.
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