Vitamin C may reduce the risk of stroke, especially in hypertensive and overweight men
Studies suggest that antioxidants, such as vitamin C, may reduce the risk of cardiovascular disease (heart disease and stroke). Antioxidants—chemicals derived from plants—help fight disease by protecting the body's cells from damage. They occur naturally in a variety of fruits, vegetables, grains, legumes, and nuts.
Research published in the June 2002 issue of Stroke: Journal of the American Heart Association again suggests that higher blood levels of vitamin C may reduce the risk of stroke. In particular, vitamin C seemed to reduce stroke risk among overweight men and men with high blood pressure—two risk factors for cardiovascular disease and stroke.
About the study
Finnish researchers studied 2419 eastern Finnish men in the Kuopio Ischemic Heart Disease Risk Factor Study. The men were between the ages of 42 and 60 and had no history of stroke when they entered the study between March 1984 and December 1989.
At the start of the study, the men were interviewed about their smoking habits and alcohol intake in the last 12 months. They also underwent the following tests:
- Fasting blood tests of vitamin C, cholesterol, and glucose levels (a test for diabetes)
- Resting blood pressure
- Exercise stress test (a test of heart function)
- Resting electrocardiogram (a test of heart function)
- Height and weight measurements (used to calculate body mass index—BMI)
In 1998, after an average of 10 years of follow-up, researchers checked the Finnish stroke and death registries to determine which men had strokes (fatal and nonfatal). Then they compared the number of strokes among men with low, moderate, and high blood levels of vitamin C.
Compared with men with the highest blood levels of vitamin C, those with the lowest levels were about 2 times more likely to have a stroke. And among the men with the lowest vitamin C levels, those who were overweight or had high blood pressure had about 2.5 times the risk of normal weight men with normal blood pressure and moderate to high vitamin C levels.
In calculating these statistics, the researchers accounted for other factors that may affect the risk of stroke, such as age, BMI, smoking, alcohol intake, cholesterol levels, diabetes, and reduced cardiac blood flow (ischemia).
Although these results are interesting, there are limitations to this study. First, participants were Finnish men between the ages of 42 and 60, so these results may not be applicable to women and older men, and people of other ethnic and racial groups. In addition, higher vitamin C levels may be an indicator that a person is eating more fruits and vegetables and less fat (high-fat diets are a risk factor for cardiovascular disease) and sodium (a risk factor for high blood pressure). If this is the case, other vitamins and minerals from fruits and vegetables may also contribute to stroke prevention. Finally, blood levels of vitamin C were only measured once at the start of the study, so we don’t know if the men maintained the same levels throughout the study period.
How does this affect you?
Will getting more vitamin C in your diet help prevent a stroke? Possibly. This study suggests that consuming vitamin C may be an important part of an overall healthy lifestyle that may help ward off cardiovascular disease, and stroke in particular. Reducing your risk of stroke also involves maintaining a healthy weight and normal blood pressure, not smoking, exercising regularly, and eating a healthful diet that is low in saturated fat and rich in fruits, vegetables, and whole grains. For some people, maintaining normal blood pressure may also include a low-sodium diet.
The National Academy of Sciences recommends the following daily intake of vitamin C for adults:
- Women: 75 mg
- Men: 90 mg
- Smokers: add an additional 35 mg per day, because metabolic turnover of vitamin C is more rapid in smokers.
Good food sources of vitamin C include:
- Oranges, grapefruit, papaya, mango and juices of these fruits
- Green and red bell peppers
- Tomatoes and tomato juice
Kurl S, et al. Plasma vitamin C modifies the association between hypertension and risk of stroke. Stroke . June 2002;33:1568-1573.
Last reviewed June 6, 2002
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