What is the impact of vegetarian diets on heart disease risk?

Vegetarian diets improve several traditional and non-traditional risk factors for heart disease. The beneficial impact of vegetarian diets on some of these risk factors is illustrated by a study that I will name the CHIP study. In this study, about 300 participants were asked to follow a low-fat vegetarian diet and have moderate physical activity, such as walking. Cholesterol levels were reduced among all participants. The biggest reduction was noticed among individuals with the highest level prior to switching to the CHIP regimen. For example, among those with a total cholesterol above 279 mg/dl prior to the study (with the average cholesterol of 303 mg/dl among men), a 33 percent reduction was observed to a level of 203 mg/dl. Among women, a 14 percent reduction was observed (from 306 mg/dl to 261 mg/dl). The so-called bad cholesterol (LDL-cholesterol) was reduced among men on average from 210 mg/dl to 138 mg/dl, or by 34 percent, whereas among women the reduction was 19 percent (from 210 mg/dl to 177 mg/dl). Additional benefits were noted among study participants. For example, blood pressure was reduced, blood sugar level was improved and reduction in body weight was reported. All of these results occurred after just 4 weeks on the CHIP program. The author of the study and developer of the CHIP program stated as follow: “Often, participants were able to decrease or discontinue antidiabetic, hypolipidemic, and antihypertensive medication. Reductions in important markers of coronary risk, such as serum lipid levels, were significant and rapid.” Research studies have shown that an improvement in risk factors results in lower risk of developing heart and other cardiovascular health conditions.

In addition, to reducing the risk of developing heart disease, vegetarian diets have been shown to be effective in reversing atherosclerosis, the underlying cause of heart and vascular health problems. This finding has been first shown in a study conducted under the direction of Dr. Ornish. He included 28 individuals between 35 and 75 years old who had coronary heart disease documented by angiography. Patients, in addition to a low-fat vegetarian diet, underwent a stress management seminar and were engaged in moderate physical activity. Atherosclerotic plagues in coronary arteries of these individuals were reduced from 40.0 to 37.8 percent after just one year of treatment. Among patients with the worst atherosclerotic plagues of 50.0 percent or higher, a reduction on average from 61.1 to 55.8 percent was noticed. Among people who did not make dietary or other lifestyle modifications included in this study, these plagues increased on average from 42.7 to 46.1 percent. Among those with initial size of these plagues higher than 50 percent, they increased from 61.7 to 64.4 percent. The results were summarized as follow: “Comprehensive lifestyle changes may be able to bring about regression of even severe coronary atherosclerosis after only 1 year, without use of lipid-lowering drugs.” Dr. Ornish and his team expended the study to five years. They saw further regression of atherosclerosis among those who adhered to vegetarian diet, while seeing a progression of disease among participants in the control group who were treated with standard treatment.