Mandatory fortification of flour with folic acid: an overdue public health opportunity

To the Editor: The editorial on mandatory fortification of flour with folic acid by Maberly and Stanley is subtitled: “The scientific benefit is clear, but translating this into practice requires advocacy”.1

The only benefit that is scientifically clear is the reduction in the incidence of neural tube defects. All the other “benefits” listed by the authors are observational and have occurred in a setting where myriad environmental changes have occurred concurrent with folic acid fortification. To imply that the reduction in the rate of heart attacks and stroke is the result of folic acid fortification is, at best, anecdotal, because it is not supported by any randomised controlled studies, and is an extrapolation from the relationship between reduced homocysteine levels and the incidence of stroke and heart disease.

The authors also did not mention the increased incidence of multiple pregnancies that has been observed with folate supplementation (relative risk, 1.02; 95% CI, 0.97–1.07).2 While this represents only a slight increase in the risks associated with the birth process, it should not be ignored when considering perceived risks. It is also possible that in a planned pregnancy where the mother is prescribed folic acid before conception, the additional folate intake from fortified flour may further increase the risk of multiple pregnancy.

It seems to me that the editorial was in fact an item of advocacy rather than a dispassionate scientific assessment of the arguments for and against mandatory folic acid fortification. At the very least, if mandatory folic acid fortification is implemented, prospective mothers will have to be made aware of the increased risk of multiple pregnancy and the as yet unknown risk of combining the fortified diet with medically prescribed folic acid.