For some years now health professionals have been advising the general public to increase their intake of fruit and vegetables to reduce the risk of specific cancers and cardiovascular disease. This review specifically looks at the effect on reducing risk of stroke.Method:
In January 1996 MEDLINE was used to identify study papers using the key words: fruit and vegetables, folic acid, homocysteine and cerebrovascular disease. All papers that could be obtained via the inter-library loan within the area were reviewed. More recent, relevant articles, up to and including March 1998, which came to attention of the authors, were also included.Results and conclusions:
Recent research has shown that beta-carotene supplements, with or without vitamin A, are not an effective means of reducing the risk of stroke. Vitamin C supplementation has not been shown to be effective but may have an effect on blood pressure. Deficiency of folic acid its effect on homocysteine concentrations is a more recent hypothesis. Consistent data link elevated levels of homocysteine with increased risk of cardiovascular disease. Certain fruits and vegetables are a good source of folic acid and those who eat more may benefit from a low plasma homocysteine and resultant lower risk of stroke. A higher consumption of fruit and vegetables may simply affect intake of total fat, potassium or sodium. However, as with any dietary association, confounding variables must not be ruled out and there are many that cannot easily be excluded: smoking, hypertension, lack of exercise and social class variations to name a few. The studies reviewed support the recommendation to eat five portions of fruits and vegetables a day.