Posted on Dec 28, 2011, 6 a.m.
A diet emphasizing vegetables, fruits, and whole grains helps to reduce stroke risk in women.
An imbalance between the production of cell-damaging free radicals and the body's ability to neutralize them, oxidative stress leads to inflammation, blood vessel damage and stiffening. Previously, a number of studies have demonstrated that antioxidants such as vitamins C and E, carotenoids and flavonoids can inhibit oxidative stress and inflammation by scavenging the free radicals. As well, antioxidants may also help improve endothelial function and reduce blood clotting, blood pressure and inflammation – factors that raise stroke risk. Susanne Rautiainen, from Karolinska Institutet (Sweden), and colleagues utilized data collected in the Swedish Mammography Cohort, identifying women ages 49 to 83 years, 31,035 of whom were free of heart disease and 5,680 women with a history of heart disease in two counties. Tracking the cardiovascular disease-free women for an average 11.5 years and the women with cardiovascular disease for 9.6 years, the team identified 1,322 strokes among cardiovascular disease-free women and 1,007 strokes among women with a history of cardiovascular disease. The researchers then factored in the dietary intake of antioxidants via data collected by food intake surveys, and calculating each participants' total antioxidant capacity (TAC) – a measurement of the free radical reducing capacity of all antioxidants in the diet. The subjects were then categorized 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% of TAC. Other contributors were whole grains (18%), tea (16%) and chocolate (5%). Higher TAC was related to lower stroke rates in women without cardiovascular disease. Women without cardiovascular disease with the highest levels of dietary TAC had a statistically significant 17% lower risk of total stroke compared to those in the lowest quintile. Among women with history of cardiovascular disease, those in the highest three quartiles of dietary TAC had a statistically significant 46 to 57% lower risk of hemorrhagic stroke compared with those in the lowest quartile. The study authors conclude that: “These findings suggest that dietary [total antioxidant capacity] is inversely associated with total stroke among [cardiovascular disease]-free women and hemorrhagic stroke among women with [cardiovascular disease] history.”
Susanne Rautiainen, Susanna Larsson, Jarmo Virtamo, Alicja Wolk. “Total Antioxidant Capacity of Diet and Risk of Stroke: A Population-Based Prospective Cohort of Women.” Stroke, December 1 2011.