Nutritional Anemia Reductions in Women of Childbearing Age Due to Food Fortification

OBJECTIVES: Review literature and conduct a meta-analysis to quantify changes in hemoglobin (Hb) and anemia prevalence among women of childbearing age after fortification of wheat flour, maize flour, rice and oil (singly or combined). METHODS: Online databases were searched for English-language documents with no restrictions on location or publication date that included longitudinal, pre-post cross-sectional, efficacy and effectiveness studies. A Bayesian arm-based meta-analysis estimated mean change and probability of Hb and anemia improvement from 17 studies. Results were stratified by fortified food and nutrients added to food. RESULTS: There was a > 95% probability that fortified wheat flour improved Hb and reduced anemia; mean Hb increased by 3.39 g/L (95% Credible Interval (CI) –0.63, 7.17) and anemia decreased by 12.8 percentage points (pp) (95% CI –23, 0.9). Likewise, fortified rice had a > 65% probability of improving Hb and reducing anemia; mean Hb increased by 2.71 g/L (95% CI –4.88, 10.64) and anemia decreased by 16.9 pp (95% CI –81, 37.8). Conversely, fortified maize flour had < 45% probability of improving Hb and reducing anemia; mean Hb decreased by 2.88 g/L (95% CI−12.85, 7.24) and anemia increased by 13.5 pp (95% CI –133,164). There was a > 90% probability that fortifying maize flour, oil, rice, and/or wheat flour with iron, folic acid or multiple micronutrients (MM) improved Hb. Mean Hb increase was highest for iron fortification (3.93 g/L, 95% CI 0.50, 7.56), followed by folic-acid fortification (3.42 g/L, 95% CI –2.08, 9.56), and lowest for MM fortification (2.11 g/L, 95% CI 0.75, 3.68). There was a > 45% probability that fortifying with any nutrients reduced anemia. Mean anemia decrease was highest for iron at 17.3 pp (95% CI –78.2, 35), followed by folic acid at 7.2 pp (95% CI −32.5, 19.7); however, fortification with MM increased anemia by 1.2 pp (95% CI –9.8, 14.9). CONCLUSIONS: There was a high probability of fortification increasing hemoglobin concentration if wheat flour or rice are fortified independently, and if foods are fortified with iron alone, folic acid alone, or a combination of multiple micronutrients. Anemia reductions were greatest for fortified wheat flour and rice and for foods fortified with iron and folic acid. FUNDING SOURCES: Global Affairs Canada.