A 14-year study of more than 85,000 British nurses shows that eating any kind of nut can significantly reduce the likelihood of heart attacks and fatal coronary disease.

The researchers, from Harvard University's Department of Nutrition, found that only 14 women who ate an ounce of nuts five or more times a week died of coronary heart disease, compared with 197 who did not eat nuts.

The reduction in risk was the same for non-fatal heart disease.

Writing in The British Medical Journal, the researchers said they took into account many other factors which could affect health, including previously diagnosed heart conditions, diet, exercise, smoking, alcohol intake, consumption of vitamins and even aspirin use.

They also managed to measure consumption of peanut butter.

Nutritious nuts

The researchers say they think nuts are good for the heart because they have beneficial effects on blood lipids, including cholesterol.

Many also contain arginine, a substance that helps the body to relax.

Most nuts contain similar nutrients so the researchers said that peanuts were also beneficial - except those with added hydrogenated fat.

Nuts are known for being full of fat and calories, but the researchers say the fat they contain is mainly unsaturated and is not harmful to the heart.

Walnuts appeared to be the top nut in terms of health as they also contain a high level of linolenic acid, which has been linked to reduced risk of heart disease because it helps keep the heart's rhythm normal.

The researchers based their study on the Mediterranean diet which is rich in nuts.

People living in Mediterranean countries are less likely to suffer heart disease.