Dr. Dean Ornish and colleagues conducted a study called "The Lifestyle Heart Trial" in the San Francisco Bay area.18 Like the two previous examples, the focus was not on bypass surgery or angioplasty. In this trial, there was a remarkably different dietary approach: instead of allowing 200-250 mg of dietary cholesterol, as did the two previous studies, the Lifestyle Heart Trial allowed a mere 5 mg of cholesterol per day. Instead of 25 to 26 percent of calories from fat, this study allowed only a 10 percent fat diet.
Total calories, however, were not restricted. Basically, the diet was nearly total vegetarian (fruits, vegetables, grains, and a small amount of nuts) with no animal products except egg whites and up to one cup per day of skim milk or non-fat yogurt. (The skim milk or non-fat yogurt contains 5 mg of cholesterol.) The results of the Lifestyle Heart Trial are tabulated in Figure 4: Results of 10% Fat and 5mg Cholesterol Diet in the Lifestyle Heart Trial. This diet is remarkably better on all counts. Notice the very large decrease in both total cholesterol and LDL "bad" cholesterol. These decreases are much greater than those that occurred in the previous two studies. Especially noteworthy is the fact that these individuals were already on a program very close to that advocated by the National Cholesterol Education Program before this study began. Before working with Dr. Ornish and his colleagues, the participants on the average were only consuming 31.5 percent of their calories from fat and 213 mg/day of cholesterol.
Dye studies of the heart blood vessels, called coronary angiograms, were made before the program started and then 12 months later. Special computerized assessments of these angiograms allowed very precise calculations of whether narrowing had worsened, stayed the same, or improved. To the amazement of many physicians, the computer comparisons revealed that 82 percent of the patients experienced a reversal of their atherosclerosis. Only 14 percent had no change, and just 4 percent worsened. This is the first study where any significant regression occurred by lifestyle changes alone, and it happened to 82 percent of participants within the short period of 12 months.
"Regression" was the term applied to the reversals in blockages that occurred in better than 8 in 10 of these participants. Overall, there was a 2.2 percent diameter regression of all lesions, which translates to a blood flow increase of 9 percent. Notice that those who began the study with the greatest stenosis or blockages, and thus had the greatest need for regression, reaped the greatest benefits. Of the coronaries that were more than 50 percent blocked there was a 5.3 percent improvement, translating to a 23 percent increase in blood flow. This is a significant amount of regression after only one year. Before this study was conducted, most physicians did not believe regression by lifestyle change was possible in any length of time--let alone within twelve months.
Note that a small percentage change in diameter stenosis provides a much greater percentage increase of blood flow. This is because the blood flow rate is mathematically proportional to the fourth power of the change in diameter (the diameter change multiplied by itself 3 times).19
