Folate and iron supplementation
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Iron and Folate Supplementation: Effects on Hemoglobin, Ferritin, and Folate Status
Research consistently shows that iron and folate supplementation, whether administered weekly or daily, improves hemoglobin and ferritin concentrations in adolescent girls and pregnant women. School-based and community-based programs providing weekly iron-folate supplements have led to significant increases in hemoglobin, serum ferritin, and serum folate levels among adolescent girls, with reductions in iron and folate deficiency rates and improved overall iron nutrition 1210. These improvements are observed regardless of initial hemoglobin values and iron doses, and the interventions are generally safe, practical, and well-tolerated 1210.
Impact on Pregnancy Outcomes: Low Birth Weight and Preterm Birth
Systematic reviews and meta-analyses indicate that iron and folate supplementation during pregnancy reduces the risk of low birth weight and may lower the odds of preterm birth, especially in African populations. Both iron-only and iron-folic acid (IFA) supplementation have been shown to significantly decrease the likelihood of low birth weight, with promising evidence for reducing preterm births as well 38. However, while iron-only supplementation may reduce perinatal mortality, evidence remains limited regarding the effects of IFA supplementation on stillbirths and neonatal mortality, highlighting the need for further research in high-risk and low-resource settings .
Hematological and Biochemical Benefits
Routine supplementation with iron and folate during pregnancy raises or maintains serum iron, ferritin, and folate levels, and substantially reduces the number of women with low hemoglobin at delivery 46. These benefits are particularly important in regions where anemia is a serious health problem. However, there is limited information on other maternal or fetal outcomes beyond improvements in hematological parameters 46.
Potential Risks and Considerations
Some evidence suggests that iron and folate supplementation may reduce zinc absorption, which could be a concern during pregnancy, especially in populations with marginal zinc intake . Additionally, animal studies indicate that iron and folate supplementation can affect white blood cell concentrations and iron metabolism, though the clinical significance of these findings in humans is not fully established 59.
Mechanisms and Biological Markers
Animal studies have explored the molecular mechanisms underlying iron and folate supplementation, showing changes in gene expression related to iron and folate transport, such as Tfr2 and Slc19a1, and increased hepcidin expression after supplementation. However, these changes at the gene level do not always translate to differences in protein levels or clear clinical outcomes .
Conclusion
Iron and folate supplementation is effective in improving hemoglobin, ferritin, and folate status in both adolescent girls and pregnant women, and can reduce the risk of low birth weight and possibly preterm birth. While the interventions are generally safe and practical, potential effects on zinc metabolism and the need for more data on broader pregnancy and infant outcomes should be considered. Expanding and scaling up supplementation programs, especially in areas with high anemia and folate deficiency rates, is supported by current evidence, but ongoing research is needed to optimize strategies and address remaining gaps.
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