But if you're still not in the habit of eating your vegetables, here's one more thing that may convince you: They can also lower your risk of stroke, according to a new study from researchers in Japan. It found that people who ate vegetables six or seven days per week had a 58% lower chance of stroke than those who ate vegetables only two days a week.
"These reductions in stroke risk are comparable to the benefits we see when someone gets their blood pressure under control," says Ralph Sacco, MD, associate chairman of neurology at Columbia University College of Physicians and Surgeons in New York. He was not involved in the Japanese study.
Back in 1977, researchers did a number of studies -- which including measuring vitamin C levels in the blood -- on more than 2,000 men and women in a rural Japanese community. Then they kept track of the study participants for the next 20 years with annual health exams. During that period, people in the study had almost 200 strokes.
Tokyo researchers have now looked at this data to see which factors increased the risk of stroke, and their results have been published in Stroke: Journal of the American Heart Association. They found that people with the lowest levels of vitamin C in their blood were 70% more likely to have a stroke, compared to those with the highest levels.
In addition to the finding about vegetables, "we found that people with a low concentration of vitamin C [in their blood] had a high risk of stroke," study author Tetsuji Yokoyama, MD, tells WebMD. "This low concentration may be due to lower intake of fruits and vegetables, smoking, drinking too much alcohol, and sedentary lifestyles. Thus, we advise people to engage in healthy behaviors such as eating fruit and vegetables frequently, not smoking, avoiding excess drinking, and being moderately physically active." Yokoyama is a research associate in epidemiology at the Medical Research Institute of Tokyo Medical and Dental University.
At the time the study began, the use of vitamin C supplements was rare in Japan, so these results are based on vitamin C derived from foods in the diet. "Since we were not studying vitamin C pills, we do not know whether vitamin C pills prevent stroke or not," Yokoyama says.
"One interesting fact from this study is that eating vegetables was very strongly correlated with stroke reduction," Melvyn Rubenfire, MD, tells WebMD. "That increases the chance these results may not be due to vitamin C alone. For example, vegetables are loaded with pyridoxine [a type of vitamin B6] and folic acid, and we know that folic acid may reduce homocysteine levels." Homocysteine is a substance in the body that is highly correlated with the incidence of stroke. Rubenfire is director of preventive cardiology and a professor of internal medicine at the University of Michigan School of Medicine, in Ann Arbor. He was not involved in the Japanese study.
"Some stories in the lay press will look at this research and say vitamin C is terrific, and we should all be taking vitamin C supplements," he says. "However, that's not what this research says. The people in this study didn't take vitamin pills; they got vitamin C from food they ate, together with many other micronutrients. The key is frequent consumption of fruits and vegetables; that is what's associated with low rates of stroke."
The basic message of this study is that you should eat a diet rich in fruits and vegetables on a daily basis, Rubenfire says. "We strongly believe that vitamin supplements are taken too often in place of a good diet. There is evidence suggesting you may even block the absorption of important nutrients if you take lots of vitamin pills, because they only supply limited forms of these nutrients."
The American Heart Association and other organizations have established that eating a healthy diet can help reduce the risk of stroke, Sacco points out.
"You really need to do something now to reduce the risk of stroke later," he says. "And just because you're eating a good diet, that doesn't mean you can smoke, drink a lot, or stop exercising. You can't look at any one of these choices in a vacuum; they all fit together."
For more information from WebMD, visit our Diseases and Conditions center on Stroke.