Evidence of Effectiveness of Flour Fortification on Iron Status and Anemia: A Literature Review

Abstract

Objectives: The effectiveness of wheat- and maize-flour fortification for improving iron status and anemia in real-world situations has not been documented.  The objective was to review published and grey literature on the public-health impact of flour fortification.  Methods: A systematic literature review was undertaken, including a search of 17 databases and an e-mail appeal for unpublished reports.  Two researchers reviewed 1881 documents.  Only studies on government-supported, large-scale fortification programs with anemia or iron outcomes measured prior to and > 12 months after initiation of fortification were included.  Results: Twelve studies describing 25 sub-groups (n=13 for children < 15 years, n=12 for women of reproductive age (WRA)) were analyzed.  Eight studies used a pre-post design, 4 included a control population, and none adjusted for possible confounding factors.  From the pre- to the post-fortification periods (and as difference-in-difference for those that included a control group), hemoglobin increased significantly in 4 of 11 studies with children and 5/11 studies with WRA; hemoglobin decreased significantly in 1/11 studies with children and 2/11 with WRA.  Anemia prevalence decreased significantly in 4/8 studies with children and 3/10 studies with WRA; anemia prevalence increased significantly in 1/8 studies with children and 2/3 studies with WRA. The prevalence of low serum ferritin statistically decreased in 1/6 studies with children and 3/3 studies with WRA.  Conclusions: Available studies confirm that large-scale fortification can positively impact iron and anemia status in children and women of reproductive age; however there is not enough evidence yet to understand under what conditions such impact is greatest.