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| |  Cholesterol-Regulating Diet Works Only When Combined With Exercise STANFORD, Calif.-- March 19, 1996 -- The low-fat, low-cholesterol diet advocated by a federally appointed panel of cholesterol experts works -- but only if the dieters add regular exercise to their health regimen, Stanford researchers report. The Step II Diet, recommended by the National Cholesterol Education Program since 1988, is designed to lower cholesterol levels in men and women who have elevated levels of the so-called "bad" cholesterol, low-density lipoprotein (LDL) cholesterol. The Stanford study investigated the effect of this diet with and without exercise on 197 men and 180 postmenopausal women with unhealthy cholesterol profiles: high levels of LDL cholesterol coupled with low levels of the "good" high-density lipoprotein (HDL) cholesterol. "We found that diet alone was not enough to lower LDL significantly in men or women with both low HDL and high LDL. But if these people also exercised, their LDL cholesterol showed a substantial and clinically important drop," said the director of the study, Marcia Stefanick, a senior research scientist at the Stanford Center for Research in Disease Prevention. For women, the LDL levels in the group combining diet with exercise were reduced on average 7.5 percent, or 12 milligrams per deciliter (mg/dl) of blood, compared with the control group. For men, the LDL levels in the diet-and-exercise group were on average 10 percent, or 15.4 mg/dl, lower than the control group. "Though after one year, most participants still had cholesterol levels that were higher than would be considered optimal by clinicians, they were well below levels that would require drug therapy," Stefanick said. "We have to think of diet and exercise as wedded in this particular population," she said. "Such individuals should not rely on diet or exercise alone to reduce their elevated risk for heart disease," said Stefanick. The principal investigator of the four-year study is Peter D. Wood, emeritus professor of medicine at Stanford University School of Medicine. Stefanick will present the new findings Friday, March 15, at 3 p.m., during the American Heart Association's 36th Annual Conference on Cardiovascular Disease Epidemiology and Prevention, held at the Fairmont Hotel in San Francisco. The results also allayed researchers' concerns that a very low-fat diet such as the Step II may be harmful. "The dieters achieved a 22 percent fat diet without raising their blood levels of triglycerides or fats, or increasing their risk of diabetes," Stefanick said. To study the effects of diet and exercise on cholesterol levels, researchers divided the men and women into four groups each: dieters (Step II), exercisers, a group that followed both the diet and exercise program, and a control group that made no lifestyle change. The researchers compared the four groups' cholesterol levels after one year of participation. At the beginning of the study, dieters met with Stanford dietitian Sally Mackey or her staff to learn how to follow the Step II Diet, which consists of less than 30 percent of calories from fat (with less than 7 percent from saturated fat) and less than 200 milligrams per day of dietary cholesterol. The Exercisers kept logs of their activities. Most jogged or walked briskly for at least 45 minutes three times a week after special training in exercise classes, supervised by Mary Sheehan, a Stanford exercise physiologist. "We focused on the clinically relevant populations -- those with high LDL and low HDL -- because they are most in need of information on non-drug alternatives to cholesterol management," Stefanick said. Figures most familiar to the general public are the total cholesterol count, which is not as useful as an indicator as the LDL and HDL counts, Stefanick said. Overall, desirable The women in the study (postmenopausal, ages 45 to 64) had initial LDL levels between 125 and 209 mg/dl and HDL levels less than 60 mg/dl. The men in the study (ages 30 to 64) had initial LDL levels between 125 and 189 mg/dl and HDL levels less than 45 mg/dl. In comparing the cholesterol levels of the control group with each of the other three groups, the researchers found that only the group combining diet with exercise had significant LDL reductions. The researchers found no significant differences between groups when comparing HDL levels. People with cholesterol levels outside the range chosen for the study might respond differently to the Step II Diet and the exercise, Stefanick noted. "Weight loss may be an essential component as well," she said. The study was funded by the National Heart, Lung, and Blood Institute.
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