Monitoring a flour fortification program for health impact provides evidence that the nutritional goals are being accomplished. Before results are assessed, however, at least two factors should be in place:
- At least 80% of the population being surveyed  is consuming foods made with fortified flour. This can be determined with household surveys and commercial monitoring.
- The fortification program has been successfully operating non-stop for at least a year to 18 months. This can be determined with internal and external monitoring.
When flour is fortified with iron, the program is sometimes judged by whether the population’s prevalence of anemia improves. This is not the best measure of success because only about half the cases of anemia worldwide are due to iron deficiency. Anemia can also be caused by other factors such as chronic infections. Only iron deficiency or iron deficiency anemia can be reduced by fortifying flour with iron.
Tests to measure iron status rather than anemia are the preferred way to monitor the health impact of fortifying flour with iron. The best indicators of iron status are ferritin and transferrin receptors which are measured in blood samples. Nationwide evaluations using individual blood samples can be very expensive and time-consuming, however. In addition, progress can only be measured if a baseline survey with the same methodology was conducted before fortification began.
For more information, see Assessing the Iron Status of Populations by the World Health Organization and U.S. Centers for Disease Control and Prevention.
If flour is fortified with folic acid, a country’s incidence of neural tube defects will very likely decline. Quality birth defects surveillance systems will show any trends in this area. If no other intervention promoted an increased intake of folic acid, and the incidence of neural tube defects declined after fortification begins, then the decline can likely be attributed to fortification.
Three types of birth defects are considered neural tube defects. These types and the International Classification of Diseases (ICD) codes for each are:
- Anencephaly - ICD10 Q00.0-Q00.1
- Encephalocele - ICD10 Q01-Q01.9
- Spina bifida - ICD10 Q05-Q005.9
Hospital systems may be able to provide data on birth defects based on those codes.
Birth Defects Surveillance: A Manual for Programme Managers is available from the World Health Organization's website. The manual focuses on population-based and hospital-based programs, particularly for countries with limited resources.
If the incidence of neural tube defects declines due to fortification but the population’s iron status does not improve, the standard for iron needs to be reviewed. A more bioavailable form of iron or a higher level of iron may be needed.
 Pena, Rosas, J., “Monitoring and Evaluation in Flour Fortification Programs: Design and Implementation Considerations.” Nutrition Reviews. 2008 vol:66 iss:3 pg:148 -162.