Healthnotes Newswire —Women who eat more whole grains are at low risk of suffering a stroke, according to a recent report in the Journal of the American Medical Association (JAMA).1
The type of stroke whole-grain eaters suffered less—ischemic (pronounced iss·kee’·mik) stroke—results from impaired blood supply to the brain and can be caused by atherosclerosis (hardening of the arteries). Ischemic stroke is the most common form of stroke suffered by Americans. The link between whole-grain consumption and prevention of ischemic stroke fits with previous reports from the same researchers2 and others3 showing that women who consume more whole grains are also at reduced risk for heart disease caused by atherosclerosis.
In the JAMA study, over 75,000 American nurses filled out food-frequency questionnaires four times between 1984 and 1994. Information from completed questionnaires was used to determine daily intake of whole-grain foods, which included popcorn, brown rice, dark bread, oatmeal, kasha (buckwheat), bulgur wheat, couscous, and whole-grain breakfast cereals.
Between 1984 and 1996, 352 of the women in this study suffered an ischemic stroke. The researchers adjusted their data to account for differences in age; risk factors, such as cigarette smoking; factors related to a decreased risk, such as use of aspirin, multivitamins, and vitamin E supplements; and other factors that might affect the risk of stroke. Those women in the top 40% of whole-grain food consumption (i.e., those who ate more than one whole-grain food on an average day) had approximately a 35% lower risk of suffering an ischemic stroke compared with the 20% of women consuming the lowest level of whole-grain foods (i.e., those who ate virtually no whole-grain products on an average day).
The whole-grain consumers tended to live more healthful lifestyles—exercising more, smoking less, consuming less fat and cholesterol, supplementing more with multivitamins and vitamin E, and eating more fruits and vegetables—compared with women who avoided whole-grain foods. Adjusting for these and related factors reduced, but did not eliminate, the protective effect associated with consumption of whole-grain foods, suggesting that something in the whole-grain foods themselves was protective against stroke.
Why does consumption of whole-grain foods reduce the risk of ischemic stroke? Higher intakes of vitamin E, folic acid, potassium, magnesium, and cereal fiber have all been linked with a lower risk of stroke and/or heart disease. Whole-grain foods are good sources of all these nutrients. The researchers studied the extent to which the association between prevention of stroke and whole-grain food consumption was determined by intake of each of these substances. They found that consumption of these nutrients was responsible for much—though not all—of the protective effects of whole-grain foods. While supplementation with these nutrients may ultimately be shown to reduce the risk of ischemic stroke, some of the protective effect of whole-grain consumption appears to come from as-yet undiscovered constituents, or from an interaction among constituents found in the whole grain.
The average American eats about one portion of whole-grain foods in two days,4 meaning that most women would need to at least double their intake of these foods to equal the intake of the women in this study who were best protected against stroke. Though death rates from stroke have been falling sharply in America for many years, the incidence of stroke has not fallen significantly since the mid-1980s. More than 600,000 Americans suffer a stroke each year, with more women suffering strokes than men. Stroke frequently leads to paralysis and permanent disability.References