The World's Healthiest Foods

Vitamin C Lowers Menís Risk of Stroke

A Finnish study published in the June 2002 issue of Stroke: Journal of the American Heart Association reports that getting enough vitamin C in the diet may decrease a man's risk of stroke, especially if the man is overweight or has high blood pressure.

Although previous studies have measured vitamin C intake from supplements and diet to see whether vitamin C protects against stroke, this study, lead by Sudhir Kurl, MD, of the Research Institute of Public Health in Finland, took a different approach. Researchers measured the amount of vitamin C actually circulating in the subjects' blood-"a better marker of the availability of vitamin C in the body," says Kurl.

Researchers evaluated 2,419 randomly selected middle-aged men (42 to 60 years) with no history of stroke at the beginning of the study and then followed these men for 10.4 years.

During this time period, 120 of the men experienced a stroke. When data recording the men's blood levels of vitamin C were checked, it was found that men with the lowest levels of plasma vitamin C (less than 28.4 micromol/L) had a 2.4-fold increased risk of stroke compared with men with highest levels of plasma vitamin C (more than 64.96 micromol/L).

The researchers then made adjustments to study data that took into consideration other potential risk factors such as body mass index (ratio of muscle to fat), systolic blood pressure, smoking, alcohol consumption, serum total cholesterol, diabetes, and exercise-induced myocardial ischemia (a lessening of blood supply to the heart due to exertion, which suggests the presence of atherosclerosis). When this data was considered, the difference in risk dropped slightly from a 2.4 to a 2.1-fold increased risk of stroke in men with the lowest blood levels of vitamin C. Researchers also factored in already present coronary heart disease and atrial fibrillation (erratic heartbeat), but these did not lessen the association between low blood levels of vitamin C and increased risk for stroke any further.

Among the men who had high blood pressure, those with the lowest vitamin C levels had a 2.6-fold increased risk of stroke, while overweight men with low blood levels of vitamin C were found to have an even higher 2.7-fold increased risk for stroke-even after adjustments were made for other risk factors.

The bottomline?

Vitamin C, a potent antioxidant and the body's premier defender against free radical attack in all water-soluble areas, may reduce the risk of stroke in a number of different ways. As an antioxidant, it quenches the activity of free radicals, which would otherwise wreak cellular havoc, and have therefore been linked not only to stroke, but a wide range of other disorders including heart disease and cancer. Vitamin C is not only extremely effective in its own right in preventing the oxidation of LDL cholesterol, it also strengthens the collagen structures of the arteries, lowers total cholesterol and blood pressure levels, raises HDL ("good") cholesterol levels, and inhibits platelet aggregation.

According to Kurl, "Stroke is a disease of older people. They are the ones that are suffering the most, and many of them are not eating a well-balanced diet. A minimum of a half glass of juice per day could contribute to this reduction in risk."

When interviewed by WebMD, registered dietician Jo Ann Hattner, spokesperson for the American Dietetic Association, agreed that incorporating more vitamin C rich foods is the best way to get the most out of this powerful vitamin.

Both Hattner and Kurl say previous studies have shown that taking vitamin C supplements doesn't necessarily have the same protective effects as getting your daily dose of vitamin C from fruits and vegetables. "We like to think that vitamin C in natural sources has some special synergy and works with other elements in the food to make it more effective in creating a line of defense," says Hattner.

The World's Healthiest Foods include a variety of sources of vitamin C, making it easy even for those who find that acidic foods, such as citrus fruits, cause heartburn or acid reflux (a back-up of stomach acids into the esophagus).

According to the World's Healthiest Foods' standard for nutrient-density, excellent sources of vitamin C include: chili peppers, parsley, broccoli, bell pepper, strawberries, oranges, lemon juice, papaya, cauliflower, kale, mustard greens, and Brussels sprouts.

To learn more about any of these vitamin C-rich foods, including quick and easy cooking and serving ideas for them, simply click on the highlighted name of the food in the above list.

To learn more about this important antioxidant, click vitamin C.

For even more suggestions for ways to enjoy vitamin C-rich foods more frequently as part of your healthy way of eating, click on the Recipe Assistant, select the foods for which you'd like some recipes from the Healthy Foods List, and click on the Submit button. A list containing links to all the World's Healthiest Foods' recipes containing the foods chosen will appear immediately below.

References: Kurl S, Tuomainen TP, Laukkanen JA, Nyyssonen K, Lakka T, Sivenius J, Salonen JT. Plasma vitamin C modifies the association between hypertension and risk of stroke. Stroke 2002 Jun;33(6):1568-73; Warner J. Low Vitamin C Increases Stroke Risk, my.webmd.com, article 1671.53300.