VRP Staff
Folic Acid fortification of food in the U.S. and Canada is linked to a reduction in stroke risk, while minorities in the U.S. are still deficient in this B vitamin, two studies indicate.
The first study explored the effects of adding folic acid to grain and cereal products, a program implemented by 1998 in the U.S. and Canada in order to reduce the occurrence of neural tube defects. In North America, fortification has produced a 25 percent decrease in this form of birth defect.
However, folic acid fortification may support other areas of our health. The study authors hypothesized that a reduction in homocysteine levels that occurred after folic acid fortification might be expected to reduce stroke mortality. Past studies have identified high homocysteine levels as a possible risk factor for strokes.
Researchers evaluated trends in stroke-related mortality before and after folic acid fortification in the United States and Canada and, as a comparison, during the same period in England and Wales, where fortification is not required. Average blood folate concentrations increased and homocysteine concentrations decreased in the United States after fortification. At the same time, stroke mortality declined from 1998 to 2002 in nearly all population strata, with an overall change per year of 2.9 percent. Analyses indicate that changes in other major recognized risk factors are unlikely to account for the reduced number of stroke-related deaths in the United States. The fall in stroke mortality in Canada decreased by 5.4 percent per year after fortification from 1998 to 2002. In contrast, the decline in stroke mortality in England and Wales did not change significantly between 1990 and 2002.
According to the study authors, “The improvement in stroke mortality observed after folic acid fortification in the United States and Canada but not in England and Wales is consistent with the hypothesis that folic acid fortification helps to reduce deaths from stroke.”
Studies have shown that folic acid is 85 percent absorbed from fortified foods, 100 percent absorbed from supplements, but only 50 percent from folate found naturally in foods.
In another study, researchers determined that even after US cereals and grains were fortified with folic acid in 1998, women in racial and ethnic minority groups had lower serum folate levels than women who were non-Hispanic whites.
This study assessed serum folate levels among 9,421 pregnant women who entered prenatal care in 1999 and 2000 in southern California. African Americans, Hispanics, and Asian/Pacific Islanders and younger subjects were more likely to have low folate levels, even after the U.S. food supply was fortified. Being overweight or obese was also associated with low folate levels. Folate levels were the highest in women who consistently used vitamins and were progressively lower among women who had just started taking vitamins, were former vitamin users or did not take vitamins.
References:
Yang Q, Botto LD, Erickson JD, Berry RJ, Sambell C, Johansen H, Friedman JM. Improvement in stroke mortality in Canada and the United States, 1990 to 2002. Circulation. 2006 Mar 14;113(10):1335-43.
Lawrence JM, Watkins ML, Chiu V, Erickson JD, Petitti DB. Do racial and ethnic differences in serum folate values exist after food fortification with folic acid? Am J Obstet Gynecol. 2006 Feb;194(2):520-6.
