Higher blood levels of vitamin C from foods correlates with reduced stroke rates; benefit traced to high intake of all food-borne antioxidants
by Craig Weatherby
In another success for fresh produce, it appears that diets rich in fruits and vegetables may reduce the risk of stroke.
Scientists from Britain's University of Cambridge analyzed diet and health data from a survey of 20,649 men and women taking part in the European Prospective Investigation into Cancer (EPIC).
The Cantabrigians found that, compared to the people with the lowest blood levels of vitamin C, those with the highest blood levels of vitamin C were 42 percent less likely to have suffered a stroke over the nearly 10-year duration of the study (Myint PK et al 2008).
While the study cannot prove a cause-effect relationship between produce intake and stroke risk, the results held true after the scientists accounted for potentially confounding lifestyle and health factors such as age, sex, smoking habits, alcohol consumption, blood pressure, cholesterol levels, weight, physical activity, and use of supplements.
It is plausible to hypothesize that vitamin C and the other antioxidants that accompany it in plant foods could be responsible for the large risk reduction detected, because laboratory experiments show that food-borne antioxidants reduce stroke risk factors in the body (e.g., inflammation, cholesterol oxidation, and platelet aggregation).
Higher vitamin C levels seen as marker for higher fruit-vegetable intake
Sebastian Padayatty and Mark Levine from the National Institutes of Health (NIH) penned an accompanying editorial, in which they made a cogent comment:
“We need readily measurable and reliable biomarkers of fruit and vegetable intake. Vitamin C is an attractive marker of fruit and vegetable intake because these foods are the primary sources of dietary vitamin C” (Padayatty SJ, Levine M 2008).
They could have added that vitamin C intake from plant foods is also and indicator for people's intake of all other food-borne antioxidants, which deliver comparable cardiovascular benefits.
Padayatty and Levine opined that people should aim for between five and nine servings of fruit and vegetables per day and pick from a wide variety of produce.
- Myint PK, Luben RN, Welch AA, Bingham SA, Wareham NJ, Khaw K-T. Plasma vitamin C concentrations predict risk of incident stroke over 10 y in 20 649 participants of the European Prospective Investigation into Cancer - Norfolk prospective population study. American Journal of Clinical Nutrition, Vol. 87, No. 1, 64-69, January 2008
- Padayatty SJ, Levine M. Fruit and vegetables: think variety, go ahead, eat! Editorial. Am J Clin Nutr. January 2008, Volume 87, Pages 5-7