The power of diet.

You've heard it a thousand times--increase the amount of fruits and vegetables in your diet to reap the benefits of plant phytochemicals and antioxidants. Antioxidants defuse free radical bombs, which cause cellular damage related to aging, atherosclerosis, and other problems. Here's more evidence of the truth in the wisdom, eat your vegetables, from the results of two research studies from prominent medical centers.

Researchers from Tufts University in Boston measured the antioxidant capacity of subjects' blood during a period of high fruit and vegetable consumption. Thirty-six healthy, non-smokers consumed two diets, with at least six weeks between trials. One diet contained ten servings per day of fruits and vegetables for 15 days. The next diet was the same but added two servings of broccoli each day on days six through ten. The researchers then sampled the subjects' blood at various points throughout the experiment and measured the antioxidant capacity of the blood plasma. (Antioxidant capacity is a measure of how well the blood can deactivate oxidizing free radicals.)

In each case, the antioxidant capacity of the subjects' blood plasma was significantly correlated with their intake of fruits and vegetables. The more they ate, the more powerful the plasma samples were in liquidating free radicals in the test tube. The researchers concluded that increasing the amount of fruits and vegetables you consume increases the antioxidant power of your circulating blood.

In another study from The Johns Hopkins Medical Institutions in Baltimore, subjects were randomly assigned to one of three diets, which were given for three weeks. Diet One was a control diet, low in fruits, vegetables, and dairy products, with 37% of calories from fat (sounds like a typical American diet). Diet Two was a diet with lots of fruits and vegetables but otherwise the same as the control diet. Diet Three was a combination diet rich in fruits, vegetables, and low-fat dairy products, and low in fat generally.. Researchers measured evidence of lipid peroxidation--looking for evidence that free radicals had oxidized blood lipids, a process thought to contribute to atherosclerosis. The investigation showed that changing to a heart healthy diet rich in antioxidants favorably affects the antioxidant capacity of blood and reduces lipid peroxidation.

So take your Granny's advice and eat your fruits and vegetables--your own little bomb squad will clean up free radicals before they detonate, causing damage you can live without.

(American Journal of Clinical Nutrition, Vol. 68, No. 68, pp. 1081-1087; Circulation, Vol. 98, pp. 2390-2395)