Effectiveness of Dietary Interventions in Prevention and Treatment of Iron-Deficiency Anemia in Pregnant Women: A Systematic Review of Randomized Controlled Trials

Nutrients

Jul 2022

DOI: 10.3390/nu14153023

Citations:34

Influential Citations:1

Systematic Reviews / Meta-Analyses

Enhanced Details

Methods

Randomized controlled trials in pregnant women (anemic and/or mixed iron status) from India, Vietnam, Indonesia, Cambodia, Tanzania, and Egypt; ages typically 15–49 years; study sizes ranged from about 86 to 495 participants; designs were randomized controlled trials comparing dietary interventions (fortified foods/beverages, regular foods, or counseling) against placebo, supplementation, or no intervention; primary outcomes included biochemical measures of anemia/iron status (hemoglobin, ferritin, transferrin saturation, etc.).

Intervention

Regimens included iron fortification of foods and beverages and dietary counseling. Specific regimens included: (1) micronutrient-fortified beverage (176 kcal/day) delivering iron 10.8 mg/day and vitamin C 144 mg/day for 8 weeks; (2) iron-fortified milk (400 mL/day) delivering 15 mg/day iron, fortified with vitamin C and folic acid; (3) iron tablets (60 mg/day iron with 250 µg folic acid) for 16 weeks; (4) tempeh-based diet with additional iron sources plus free iron and folic acid tablets; (5) corn-soya blend plus vitamins (CSB Plus) with iron ≈13 mg per daily portion and vitamin C; (6) Trials of Improved Practices (TIPs) involving dietary counseling with 12 weeks duration; (7) lactoferrin sachets 100 mg twice daily for 4 weeks plus health education; (8) total dose infusion of low-molecular-weight iron dextran; (9) diet alone counseling arm; durations ranged from 4 weeks to 6–8 months or longer depending on study; some regimens included additional iron-rich foods (meat, fish, legumes, vegetables) to enhance absorption.

Results

Dietary interventions to increase iron intake or improve iron bioavailability consistently improved iron status or prevented/treated iron-deficiency anemia in pregnancy across multiple RCTs. Fortified foods/beverages and iron-rich dietary modifications increased hemoglobin and iron stores and reduced anemia risk; counseling-only approaches also showed benefit. These findings support integrating dietary fortification and nutrition counseling into prenatal care as a feasible approach to prevent/treat iron-deficiency anemia during pregnancy, potentially aiding adherence where iron supplementation faces tolerability or access challenges.

Limitations

Risk of bias varied across trials (some with moderate to high risk due to randomization, deviations from intervention, or selective reporting); limited number of studies with heterogeneous regimens, populations, and durations; outcomes are largely biochemical with limited clinical endpoints.

Abstract

Pregnant women are among the population groups most vulnerable to the development of anemia, as the overall iron requirement during pregnancy is significantly higher than in non-pregnant women. The aim of the systematic review was to assess the effectiveness of dietary interventions in the prevention and treatment of iron-deficiency anemia in pregnant women based on randomized-controlled trials. The systematic review was based on the PRISMA guidelines and is registered in the PROSPERO database (CRD42021261235). The search was conducted within PubMed and Web of Science databases for the period until June 2021. The included randomized controlled trials presented effectiveness of dietary interventions in prevention and treatment of iron-deficiency anemia in pregnant women. From the total number of 7825 screened records, the final number of seven studies were included in the systematic review. The procedure of screening, inclusion, reporting, and assessment of the risk of bias while using the revised Cochrane risk of bias tool for randomized trials was conducted by two independent researchers. The studies included in the systematic review were conducted in populations of anemic pregnant women, or mixed populations of anemic and non-anemic pregnant women. The interventions described within the studies were associated with including fortified products, regular products, or dietary counselling. They were based on providing an increased amount of iron, providing an increased amount of multiple nutrients, or general counselling only, while effectiveness was compared with effectiveness of the placebo, supplementation, or control group. The study duration was diversified from a few weeks to half a year or longer. The major biochemical measure assessed within the included studies was hemoglobin. All applied dietary interventions, based on providing increased amount of iron, providing increased amount of multiple nutrients, or general counselling only, were effective. The majority of included studies were assessed as ones of a medium risk of bias. For some studies a high risk of bias was indicated, which resulted from a risk of bias arising from the randomization process, due to deviations from the intended interventions, and in selection of the reported result. Considering this fact, more randomized controlled trials should be planned and conducted in a rigorous manner to confirm the formulated observations of effectiveness of the studied interventions based on providing an increased amount of iron, providing an increased amount of multiple nutrients, or general counselling only. show less