ObjectivesReview 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). MethodsOnline 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. ResultsThere 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). ConclusionsThere 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 SourcesGlobal Affairs Canada.