By Lisa Ellis
InteliHealth News Service
November 10, 2003
ORLANDO, Fla. — People with heart disease or a strong risk of developing it lost weight, reduced blood pressure and cholesterol and increased their exercise capacity after 12 weeks on a very-low-fat, vegetarian diet and exercise program, a study concludes.
The study, funded by a Pennsylvania health-insurance company, was presented by Dean Ornish, M.D., creator of the diet, at the American Heart Association's annual Scientific Sessions.
The Ornish program used in the study includes a diet containing less than 10 percent of calories from fat, about three hours a week of moderate exercise, one hour a day of stress management, and a professionally run support group.
About 250 members of Highmark Blue Cross Blue Shield, a Western Pennsylvania insurer, took part in the program. Although Dr. Ornish presented the study as the principal investigator, a news release from Highmark stated that the company's own staff compiled the statistics.
More than half of the participants had known heart disease, 22 percent had high blood pressure, and others had various conditions that increase heart-disease risk, including high cholesterol and diabetes.
After 12 weeks, group members had lost an average of 6 percent of their body weight, and blood pressure dropped more than 7 percent. Blood sugar dropped 13 percent to 19 percent, depending on the measurement used. LDL or "bad" cholesterol dropped 17 percent.
As in other studies of the Ornish diet, HDL or "good" cholesterol also fell.
In a news conference, Dr. Ornish contended that high HDL is not necessary for heart health in people who eat very little fat. HDL helps to reduce the plaque that can obstruct coronary arteries.
"There's less garbage, so your body needs fewer garbage trucks [HDL] to get rid of it," he said. Ornish is a professor of medicine at the University of California, San Francisco and president of the Preventive Medicine Institute in Sausalito, Calif.
Ornish said the Medicare program recently decided to fund a demonstration project using the Ornish diet in 1,800 older adults.
A study from Tufts University presented here also found that the Ornish diet and three other popular diets all were effective in producing weight loss and lowering LDL.
The Atkins, Zone and Weight Watchers diets all raised HDL as well, while the Ornish diet did not, said Michael L. Dansinger, M.D., assistant professor of medicine at Tufts.
"What we found was that those who followed their assigned diet closely were pretty similar in their risk reduction" for heart disease, Dr. Dansinger said.
But the dropout rates were higher — about 50 percent — with the Ornish and Atkins diets, compared with 30 percent for the other two, he said.
For those who remained, Dr. Dansinger said, the Ornish diet reduced LDL about 10 percent — more for those who followed carefully. Reductions were 4 percent to 6 percent for Weight Watchers and Zone and 2 percent to 3 percent for Atkins, he said.
For purposes of comparison, the study focused on only the diet component of the four programs, not exercise or support groups. Participants attended four group classes in a two-month period and decided for themselves how closely to follow the diet, Dr. Dansinger said. Results were measured after one year.
Only 40 people were randomly assigned to each group. Dr. Dansinger said that this is the first study to compare the four diets in this way but that he believed larger studies would show similar results.
More and larger studies are needed, he said. "The challenge is for doctors to learn how to match patients with [diets] that work best for them."
Weight loss experts agree that the biggest challenge with weight loss is keeping the weight off. This study did not look at how to do that, or whether the diets would protect or harm the heart if followed for long periods of time.
