In this reversal, fatty deposits lining the arteries leading into the heart are reduced in size, increasing the flow of oxygen to the heart muscle, which should help to lower the risk of a deadly myocardial infarction .

The first study to show this positive change was the so-called Leiden Intervention Trial, a two-year investigation carried out with 39 patients who suffered from angina pectoris (pain associated with insufficient blood flow to the heart muscle). The 39 subjects adopted a vegetarian diet and limited cholesterol intake to 100 mg per day.

During the two-year period, total cholesterol levels dropped by an average of 10 per cent. However, artery blockages actually worsened in 21 of the patients, stayed the same in 11 subjects, and got better (the arteries opened up a bit) in only seven individuals. These lucky seven were the ones who ended up with the lowest cholesterol readings; only one of the seven had persistent angina at the end of the study. The message was that a vegetarian, low-cholesterol diet could help SOME - but not all - people expand their coronary arteries.

In a second study, the Lifestyle Heart Trial, patients with coronary heart disease (CHD) followed a low-fat diet (fat comprised less than 10 per cent of total calories), took in less than 200 mg of cholesterol per day, and exercised at 50-80 per cent of maximal heart rate for three hours per week. A second group of CHD patients (the control group) followed a less restrictive diet and exercised infrequently.

After one year, the control group's coronary arteries had actually narrowed by an additional 10 per cent, while the exercise-diet group opened up their arteries a notch. 82 per cent of the subjects in the exercise-diet group improved artery health, against just 42 per cent of controls. Only 18 per cent of the exercise-diet group had narrower arteries after one year, compared with 53 per cent of controls. A combination of exercise and a spartan diet looked like a decent way to reduce atherosclerosis.

Several other studies have shown similar effects. The take-home lesson from these investigations is that dietary changes can indeed open up one's coronary arteries. The actual effects of exercise by itself are difficult to predict, however, because none of the current studies have looked at exercise alone without a dietary intervention. However, the good news is that coronary-artery blockages are not irreversible; it appears that a healthier diet - and perhaps a healthier exercise programme - can chip away at fatty deposits which block precious oxygen from getting to your heart.

(Reversing Coronary Artery Disease, The Physician and Sportsmedicine, vol. 22(11), pp. 59-64,1994)