High vitamin C level linked to decreased stroke risk

NEW YORK (Reuters Health) - A person's level of vitamin C may predict his or her likelihood of having a stroke, according to a long-term study of some 20,000 middle-aged and older residents of Norfolk, United Kingdom.

During an average follow-up of 9.5 years, 448 strokes occurred in the study population. Researchers found that people with the highest vitamin C concentration at the start of the study had a 42 percent lower risk of stroke over 10 years compared to those with the lowest levels of vitamin C.

The protective effect of vitamin C against stroke remained after accounting for factors that could affect the risk, such as age, sex, smoking, alcohol intake, body mass index, blood pressure, cholesterol, physical activity, diabetes, prior heart attack, supplement use, and social class.

Dr. Phyo K. Myint from the University of Cambridge, UK, and colleagues report the study results in the American Journal of Nutrition.

Myint noted that the level of vitamin C in the blood is a "good biomarker of fruit and vegetable consumption, which have many nutrients that may be biologically active and protective for stroke; this study supports the existing body of evidence that indicates the high fruit and vegetable consumption is protective for stroke."

In a related commentary, Drs. Sebastian J. Padayatty and Mark Levine of the National Institutes of Health in Bethesda, Maryland, emphasize that fruits and vegetables are associated with many health benefits, including a reduction in strokes. "Because we do not know why or how the benefit occurs or what fruits and vegetables are effective, it is prudent to consume a wide variety," they add.

"The optimum intake for reduction of stroke and cardiovascular disease is unknown," they point out, "but an intake of 5-9 servings daily is associated with benefit and the public should aim toward the higher intakes."

SOURCE: American Journal of Medicine, January 2008.