THURSDAY, Dec. 1 (HealthDay News) -- Diets rich in antioxidants from fruits, vegetables and whole grains appear to lower a woman's odds for a stroke, even if she has a prior history of heart disease, new research shows.
The Swedish study, which appears Dec. 1 in the journal Stroke, involved more than 31,000 women without heart disease plus almost 5,700 women with a history of heart disease. The women, aged 49 to 83, were followed for an average of 11.5 years (for the heart disease-free group) or almost 10 years (the heart disease group).
During the follow-up, more than 1,300 strokes occurred in the heart disease-free group and more than 1,000 strokes occurred in the heart disease group.
The researchers then used dietary information to determine the women's "total antioxidant capacity (TAC)," a measurement of the power of these food-borne compounds to cut down on disease-linked "free radicals" in cells. Cell damage caused by free radicals can lead to inflammation and damage and stiffening of blood vessels.
Among women with no history of heart disease, those with the highest levels of diet-based antioxidants had a 17 percent lower risk of stroke than those with the lowest levels.
Benefits extended to women who'd already suffered heart disease. Among this group, women with higher levels of dietary antioxidant capacity had up to a 57 percent lower risk of hemorrhagic (bleeding) stroke compared to those with the lowest levels.
According to the study authors, fruits and vegetables contributed about 50 percent of antioxidant capacity in women with no history of heart disease who had the highest TAC. Other contributors included whole grains (18 percent), tea (16 percent) and chocolate (5 percent).
The study authors noted that the effect remained even after they accounted for other factors that often correlate with healthy diets, such as exercise or avoidance of smoking.
"Eating antioxidant-rich foods may reduce your risk of stroke by inhibiting oxidative stress and inflammation," first author Susanne Rautiainen, a doctoral student at the Karolinska Institute in Stockholm, said in a journal news release. "This means people should eat more foods such as fruits and vegetables that contribute to total antioxidant capacity."
Other experts agreed.
"We've known for a long time that including antioxidants in the diet can have a positive effect on a variety of conditions, and there is no downside to including more of these foods in your diet," said Karen Congro, a nutritionist and director of the Wellness for Life Program at The Brooklyn Hospital Center in New York City.
"It would be very helpful to test these findings in a large clinical trial to determine how a high antioxidant diet impacts stroke," she added. "Since antioxidants are anti-inflammatories, their inclusion in a diet can have a positive impact for people at risk for a variety of conditions."
And one heart expert noted that diet, not supplements, may remain the best source of antioxidants.
"This [heart-healthy] diet was highest mostly in fruits and vegetables, along with whole grains, tea and chocolate, whose antioxidant capacity, including vitamin C and E, carotenoids, and flavonoids have a beneficial effect," said Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City. She noted that although many prior trials "did not show benefit of antioxidant supplementation, clearly a diet high in antioxidants may provide protection against cardiovascular disease."
The National Stroke Association has more about women and stroke.