Swedish women who ate an antioxidant-rich diet had fewer strokes regardless of whether they had a previous history of cardiovascular（心血管的） disease, in a study reported in Stroke: Journal of the American Heart Association. "Eating antioxidant-rich foods may reduce your risk of stroke by inhibiting oxidative stress（氧化应激） and inflammation," said Susanne Rautiainen, M.Sc., the study's first author and Ph.D. student at the Karolinska Institutet in Sweden. "This means people should eat more foods such as fruits and vegetables that contribute to total antioxidant capacity."

Oxidative stress is an imbalance between the production of cell-damaging free radicals and the body's ability to neutralize them. It leads to inflammation, blood vessel damage and stiffening.

Antioxidants such as vitamins C and E, carotenoids（类胡萝卜素） and flavonoids（黄酮类） can inhibit oxidative stress and inflammation by scavenging（清除，净化） the free radicals. Antioxidants, especially flavonoids, may also help improve endothelial function and reduce blood clotting, blood pressure and inflammation.

"In this study, we took into account all the antioxidants present in the diet, including thousands of compounds, in doses obtained from a usual diet," Rautiainen said.

Researchers collected dietary data through a food-frequency questionnaire. They used a standard database to determine participants' total antioxidant capacity (TAC), which measures the free radical reducing capacity of all antioxidants in the diet and considers synergistic effects（协同效益） between substances.

Researchers categorized the women according to their TAC levels -- five groups without a history of cardiovascular disease and four with previous cardiovascular disease.

For women with no history of cardiovascular disease who had the highest TAC, fruits and vegetables contributed about 50 percent of TAC.

Other contributors were whole grains (18 percent), tea (16 percent) and chocolate (5 percent).