Written by Christian Nordqvist
Females who consume lots of fruit, vegetables and grains have a lower risk ofstroke, even if they have a history of cardiovascular disease, compared to women who don’t, researchers from the Karolinska Institute, Sweden, reported in Stroke.
First author, Susanne Rautiainen, said: “Eating antioxidant-rich foods may reduce your risk of stroke by inhibiting oxidative stress and inflammation. This means people should eat more foods such as fruits and vegetables that contribute to total antioxidant capacity.”
Free radicals, oxidative stress and antioxidants
Oxidative stress occurs when there is an imbalance between the production of free radicals, which damage cells, and the human body’s ability to neutralize them or repair the subsequent damage, which results in blood vessel damage, stiffening and inflammation. Oxidative stress can be inhibited by antioxidants, such as vitamins E and C, flavonoids, and carotenoids – antioxidants scavenge the free radicals. Flavonoids, for example, can help improve endothelial function, blood pressure, inflammation, and reduce blood clotting.
According to Medilexicon’s medical dictionary: An antioxidant is an agent that inhibits oxidation; any of numerous chemical substances including certain natural body products and nutrients that can neutralize the oxidant effect of free radicals and other substances. Rautiainen and team gathered data from the Swedish Mammography Cohort and identified 31,035 women who were free of cardiovascular disease and 5,680 others with a history of cardiovascular disease in two counties. They were aged from 49 to 83 years. Among the cardiovascular-disease free women they identified 1,322 cases of stroke, and 1,007 cases in the others.
With the use of a food-frequency questionnaire, they gathered data on the women’s eating habits. They determined the women’s TAC (total antioxidant capacity). TAC measures the free radical-reducing capacity of all antioxidants in the diet and takes into account the synergistic effects substances might have on each other. The women were then categorized according to their TAC levels – there were nine groups, five among those with no history of cardiovascular disease and four with a history of cardiovascular disease.
Fruit and vegetables contributed to about half the TAC for women in the highest quintile. Other key foods included whole grains at 18%, tea 16% and chocolate 5%. Those in the highest quintile of dietary TAC had a 17% lower risk of developing stroke compared to those in the lowest quintile – the authors described this as a “statistically significant difference”. The risk of hemorrhagic stroke was from 46% to 57% lower among the women in the highest three quartiles of dietary TAC compared to those in the lowest quintile.