FRIDAY, March 5, 2004 (HealthDayNews) -- The folic acid found in enriched grain products may be helping to reduce stroke deaths in the United States.
That's the finding of a federal study presented March 5 at the American Heart Association's Annual Conference on Cardiovascular Disease, Epidemiology and Prevention in San Francisco.
The fortification of these foods with folic acid, required by the U.S. Food and Drug Administration since 1996, was designed to reduce the number of children born with neural tube defects, such as spina bifida. But researchers from the U.S. Centers for Disease Control and Prevention, as well as others, suspected the fortification might also offer a secondary benefit -- a reduction in deaths from stroke.
Quanhe Yang, a CDC epidemiologist, and his co-researchers estimate in their study that 31,000 stroke-associated deaths and 17,000 deaths related to heart disease may have been prevented annually since the fortification was implemented. They analyzed national death certificate data to evaluate the number of deaths from stroke and heart disease in the United States for people aged 40 and older.
Folic acid reduces concentrations of homocysteine, an amino acid in the blood, says Yang. Too much homocysteine has been associated with a higher risk of stroke and heart disease.
"High levels of homocysteine [are] an independent risk factor for cardiovascular disease," Yang says. "Overall, the fortification resulted in a decline of stroke deaths of 10 to 15 percent in the three years after [fortification was implemented], in 1999 to 2001, compared to the three years before, 1994 through 1996."
"This decline cannot be explained by changing other major risk factors, such as changes in people's smoking habits, prevention of diabetes or high cholesterol," he says.
High homocysteine levels somehow cause an "insult" to the blood vessel wall, Yang says, and weaken the vessel, making it more vulnerable to damage.
About 700,000 people in the United States suffer a stroke each year, according to the American Heart Association.
Dr. William Buxton, an assistant clinical professor of neurology at the UCLA David Geffen School of Medicine in Los Angeles, says the new study puts concrete numbers on something experts have long suspected.
"Supplementing with folic acid and other B vitamins may have some benefit both in the prevention of first strokes and in the prevention of recurrent strokes," says Buxton.
More research is needed, he adds, to determine the exact mechanism of the action of the folic acid.
Buxton stresses consumers should not take folic acid or other B vitamins without talking to their doctor first.
The current daily recommended dietary allowance (RDA) of folic acid is 400 micrograms, an amount typically found in a multivitamin.