The study showed for the first time that shedding excess pounds decreases activity of a key enzyme known to play a central role in high blood pressure, said Dr. Joyce Harp, associate professor of nutrition and medicine at the UNC schools of public health and medicine. Less body weight translates into lower blood pressure, the study confirmed, and hence lower risks for cardiovascular disease, stroke, kidney disease and other health problems.
Published in the current (October) issue of the journal Obesity Research, the investigation was conducted at Emory University in Atlanta where Harp previously worked.
"We intensively studied 16 obese but otherwise healthy, non-diabetic adults on the clinical research unit," said Harp, "Our goal was to determine if blood pressure regulating enzymes and hormones that are produced in fatty tissue are lowered by modest dietary weight loss."
After first conducting studies in rodents, which demonstrated that all the components of the renin-angiotensin system were produced in fat tissue, Harp and colleagues extended their work to humans, she said. Volunteers were supplied with calorie-restricted, defined diets that enabled them to lose modest amounts of weight, about 5 to 10 percent.
Researchers found that in addition to significant decreases in blood pressure, angiotensin-converting enzyme (ACE) activity was suppressed most dramatically with weight loss, she said. Plasma renin activity and serum aldosterone levels also declined, but those changes were not as great as the drop in ACE activity.
ACE activity while standing up, which Harp and the others showed for the first time is higher than when lying down, declined
Contact: David Williamson
University of North Carolina at Chapel Hill