A program of improved diet and daily exercise for less than one month can significantly reduce the risk of heart disease long before substantial weight loss occurs, reports a UCLA-led team.
The study found that obese men can lower their blood pressure and reduce other key health threats in a three-week program of daily exercise and a low-fat, high-fiber diet — even though they are still obese at the study’s conclusion and lose only a few pounds.
“Weight loss takes time, but fortunately, we can ease high blood pressure and the risk of atherosclerosis and heart disease while — or even before — a person sheds excess pounds,” said R. James Barnard, senior author of the study and professor of physiological science at UCLA.
Elevated blood pressure, which affects more than 50 million Americans, is a hallmark risk factor for congestive heart failure, kidney disease, coronary artery disease and stroke. The study also measured changes in cholesterol, glucose, insulin, blood pressure, nitric oxide availability and oxidative stress.
“This is the first study to show that this type of diet and exercise can reduce oxidative stress, lower blood pressure, and improve risk factors for other chronic diseases in a very short time,” Barnard said.
The findings were reported October 23, in a rapid-access issue of the journal Circulation. The study was funded in part by the National Institutes of Health.
The research team — which included Barnard, UC Irvine professor of medicine and chief of nephrology Nosratola Vaziri, and UCLA postdoctoral fellow Christian Roberts — studied 11 men ages 38 to 72 who voluntarily enrolled in the Pritikin Longevity Center 21-day residential diet and exercise program. Each man had a body mass index of 30 or greater; seven of the men had hypertension (defined as blood pressure of more than 140 systolic or more than 90 diastolic).
The exercise program consisted of brisk walking on a treadmill for 45 to 60 minutes a day.
Meals consisted of less than 10 percent of calories from fat, 15 to 20 percent from protein and 70 to 75 percent from unrefined carbohydrates. Carbohydrates were derived from five servings of high-fiber whole grains, four servings of vegetables and three servings of fruit daily. Grains, vegetables and fruit were served all-you-want buffet style. The men had one serving of chicken or fish for dinner.
By the end of the program, none of the seven hypertensive men had high blood pressure. Systolic blood pressure was reduced by 14 percent, diastolic blood pressure by 10 percent and oxidative stress by 28 percent, while nitric oxide availability improved by 28 percent. Total cholesterol decreased by 19 percent, insulin levels by 46 percent and blood glucose by 7 percent.
Nitric oxide helps prevent heart disease in several ways, including helping to relax blood vessels, thus reducing blood pressure. It also prevents cells in the walls of blood vessels from proliferating and clogging the arteries, a process that contributes to atherosclerosis. Oxidative stress refers to the presence of oxygen free radicals that can attack cells and tissues and contributes to cardiovascular disease and other health problems.
Although body weight and body mass index decreased slightly (about 4 percent each), the men were all still obese at the end of the three-week program.
“Within three weeks, we showed normalization of blood pressure and mitigation of other atherosclerotic risk factors, all of which will reduce the risk of chronic disease if maintained as part of a lifestyle change,” Roberts said.
The researchers caution that changes in diet and exercise must continue in order to maintain the health gains.
“If you return to an inappropriate diet and stop exercising, you will no longer benefit, and in fact you will regress,” Roberts said.
The journal Circulation is published by the American Heart Association.