A diet rich in fruit and vegetables may help protect middle-aged men from stroke, still the third leading cause of death in the US. For every extra three servings a day of fruit and vegetables, you could reduce the risks of stroke by 22 per cent, res

On that basis, 15 servings a day would theoretically reduce your risks to nil. A serving, as defined by the researchers, is half a cup of fruit or vegetables.

Fruits ranged from the "watery" varieties of peaches, oranges and orange juice, to "average" fruits consisting of apples, bananas and apple juice. The third category was sweet fruits, which included canned and frozen fruits. There were 10 categories of vegetables, including roots, raw and green vegetables, cooked leafy vegetables, then tomato sauce, peas and lima beans, baked beans, corn, potatoes and sweet potatoes and potato chips.

For 20 years, researchers from Harvard Medical School tracked a group of 832 middle-aged men-aged between 45 and 65 to see how varying diets affected the risk of stroke.

Of the two, researchers found that vegetables offered more protection than fruit. The reasons, though, seem less clear. Perhaps the best indications come from studies into vegetarian diets, which discovered they tend to lower blood pressure, as dietary fibre apparently does (JAMA, April 12, 1995).

Rather obviously, Finnish researchers have concluded that when the major heart risk factors smoking, blood pressure and cholesterol are reduced, so are the risks of developing a stroke (BMJ, April 8, 1995).

A fruit and vegetable diet can also help protect against cancer, heart disease and cataracts, says Dr Bruce Ames, director at the National Institutes of Environmental Health Sciences Center at the University of California.

Interviewed in the Journal of the American Medical Association (JAMA), Dr Ames points out that people in the bottom quartile of dietary intake of fruit and vegetable have twice the rates of cancer as those in the top quartile. The rates of heart disease and cataracts are also much higher in people not eating enough fruit and vegetables (JAMA, April 12, 1995).