Context.

More than 80 countries fortify flour, yet the public health impact of this intervention on iron and anemia outcomes has not been reviewed.

Objective.

The objective of this systematic review was to review published and gray literature pertaining to the impact of flour fortification on iron and anemia.

Data Sources.

A systematic review was conducted by searching 17 databases and appealing for unpublished reports, yielding 1881 documents.

Study Selection.

Only studies of government-supported, widely implemented fortification programs in which anemia or iron status was measured prior to and ≥12 months after initiation of fortification were included.

Data Extraction.

Details about the design, coverage, compliance with national standards, and evaluation (e.g., anemia prevalence before and after fortification) of flour fortification programs were extracted from the reports.

Data Synthesis.

Thirteen studies describing 26 subgroups (n = 14 for children ≤15 y, n = 12 for women of reproductive age) were included. During the period from pre- to postfortification (and as difference-in-difference for those studies that included a control group), there were statistically significant decreases in the prevalence of anemia in 4 of 13 subgroups of children and in 4 of 12 subgroups of women of reproductive age as well as significant decreases in the prevalence of low ferritin in 1 of 6 subgroups of children and in 3 of 3 subgroups of women of reproductive age.

Conclusions.

Evidence of the effectiveness of flour fortification for reducing the prevalence of anemia is limited; however, evidence of effectiveness for reducing the prevalence of low ferritin in women is more consistent.