After folic acid fortification of enriched grain products was fully implemented in 1998, deaths due to strokes dropped rapidly in the U.S. and Canada, according to a report in the American Heart Association’s journal Circulation.
The main reason for folic acid fortification was to reduce the number of babies born with neural tube defects such as spina bifida. The present findings suggest, however, that there may have been an unintended benefit.
There is “accumulating, controversial evidence” that homocysteine — an amino acid in the blood — is a risk factor for stroke and heart disease, Dr. Quanhe Yang, from the Centers for Disease Control and Prevention in Atlanta, said in a statement. Folate decreases homocysteine levels, which may help explain the drop in stroke deaths.
Yang’s team compared stroke mortality trends between 1990 and 2002 in the US and Canada with those in England and Wales, where folate fortification is not required.
Stroke mortality was already falling in the US and Canada from 1990 to 1997, but in 1998 a precipitous drop began, the report indicates. In the US, the annual decrease in mortality during the earlier period was 0.3 percent, whereas starting in 1998 the reduction was 2.9 percent. Similar results were seen in Canada.
By contrast, stroke mortality rates did not decline significantly in England and Wales between 1990 and 2002, the report indicates.
“If folic acid fortification is responsible for even a fraction of the accelerated improvement we observed, this public health benefit is an important bonus to the reduction in neural tube defect rates previously demonstrated,” Yang and colleagues conclude.
