Walnuts-RX for high cholesterol.

Diet doesn't act alone in influencing cholesterol levels, but it is important. Traditionally, doctors have advised patients with high cholesterol to eat a Mediterranean diet, low in animal fats, high in fruits, vegetables, and olive oil (monounsaturated fat). Several recent studies show that adding walnuts to your diet may reduce cholesterol levels further. Studies have shown that walnut extracts, called polyphenolic compounds, prevent the oxidation of cholesterol. Oxidized cholesterol contributes to plaques that cause heart disease and stroke.

One study from Spain, compared two diets--one a normal Mediterranean diet, another the same diet but with walnuts substituted for some of the olive oil and other high fat foods. The diet included 11 walnuts a day, replacing 35% of the fat calories as compared to the normal diet, for six weeks. Total levels of fat and calories were about the same for the two diets. The subjects were 55 men and women (average age 56) who were being treated for high cholesterol. At the end of the study, the walnut group had significantly lower total cholesterol as well as lower low-density lipoprotein levels (LDL, the bad cholesterol) as compared to the regular Mediterranean diet. The researchers concluded that substituting walnuts for part of the monounsaturated fat in a cholesterol-lowering Mediterranean diet further reduced total and LDL cholesterol levels in men and women with high cholesterol.

In another study from Japan, researchers compared a diet with 12.5% of its energy from walnuts to a control diet. The walnuts were substituted for other high-fat foods like meat and fat. The results were similar to the Barcelona study. Both total cholesterol and LDL levels were significantly lower among the walnut-eaters than those in the control diet. Substituting walnuts for some of the fat in a normal diet reduces both total cholesterol and LDL levels.

The trick is to eat walnuts instead of other fats. Walnuts are fat and calorie dense. Even though the polyphenolic compounds appear to have healthy benefits, you must also cut back in other intake, which isn't always easy. If not, gaining weight would be an unwanted side-effect.

(Journal of Nutrition, 2001, Vol. 131, No. 11, pp. 2837-2842; Annals of Internal Medicine, 2000, Vol. 132, No. 7, pp. 538-546; Journal of Nutrition, 2000, Vol. 132, No. 2, pp. 171-176)