Food fortification has been shown to be an impactful approach to improve micronutrient status and related functional outcomes for some nutrients in some food vehicles, but there are still calls to strengthen the evidence base, particularly programmatic evidence. The primary objectives of this chapter are to review methodologies used to date to evaluate the impact of food fortification programs in populations, discuss the strengths and limitations of these methodologies and resulting evidence, and provide recommendations on how such methodologies could be improved.
The majority of the evidence for food fortification programs has been generated using observational methodologies (ecological, repeat cross-sectional, and cohort designs). While such methods can be cost-efficient and less complex than experimental impact evaluation designs, they present important limitations for attribution and for assessing impact on functional outcomes. Using impact pathways to guide evaluations and prioritizing impact assessment in programs with appropriate design (i.e., in populations with potential to respond and appropriate food vehicles/fortificants) and implementation (i.e., compliance monitoring and enforcement, high coverage in populations with potential to respond) could substantially increase the quality of evidence for food fortification.