High Vitamin C Blood Levels Linked to Reduced Stroke Risk

A newly published study has found a striking association between elevated vitamin C blood levels and reduced risk of stroke.¹ The British study involved 20,649 men and women between the ages of 40 and 79 with no history of prior stroke. The individuals were part of the "European Prospective Investigation into Cancer-Norfolk Prospective Population Study." The research was published in the January issue of the American Journal of Clinical Nutrition.

Strokes are an interruption of blood supply to the brain typically caused by either a blood clot or ruptured blood vessel in the brain. According to the American Stroke Association, there is a stroke every 45 seconds in the US. Strokes are also reported to be the leading cause of disability and the third largest killer in the US and Europe.

At the onset of the study, health and lifestyle questionnaires were completed by the participants. A blood sample was collected to measure vitamin C levels at the baseline. The researchers followed the subjects for nine and one half years and recorded 448 strokes. Those in the quartile with the highest average blood levels of vitamin C, measuring greater than 66 micromoles per liter, had 42% lower risk of stroke than those in the lowest quartile of vitamin C levels (less than 41 micromoles per liter). The researchers adjusted for other factors such as age, gender, smoking habits, alcohol consumption, blood pressure, cholesterol levels, BMI (Body Mass Index), physical activity, and use of nutritional supplements. When the researchers went back and excluded those individuals who took vitamin C-containing supplements, the results were the same, indicating that the benefits could be garnered from foods rich in vitamin C as well as supplements.

The researchers stated that it is "an intriguing possibility is that the plasma vitamin C concentration is a good marker of a wider range of health behaviors, such as fruit and vegetable consumption, that may be protective against stroke." They went on to state that "it is also plausible that vitamin C may biochemically affect stroke risk."

The researchers concluded that "the magnitude of the association between plasma vitamin C and subsequent stroke is substantial and independent of known major risk factors for stroke." It therefore may be a good indicator of stroke risk, given that nearly half of all strokes are not explained by typical cardiovascular disease risk factors.

A study published in March 2007 that found vitamin C supplementation may help protect against a wide range of health disorders, including immune system deficiencies, cardiovascular disease, prenatal health problems, eye disease and cancer.

Learn more about vitamin C and its potential benefits here.

1. Myint, P. K., R. N. Luben, et al. (2008). "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." Am J Clin Nutr 87(1): 64-9.

2. Moyad, M. A., Maile A. Combs (2007). "Vitamin C Dietary Supplements: An Objective Review of the Clinical Evidence. Part I." Seminars in Preventive and Alternative Medicine 3(1): 25-35.