Low-Carb Diet Lowers Blood Pressure

DURHAM, N.C.A low-carbohydrate diet proved better at lowering blood pressure than the weight-loss drug orlistat, according to researchers at Veterans Affairs Medical Center and Duke University Medical Center.

The findings send an important message to hypertensive people trying to lose weight, said William S. Yancy, Jr., MD, lead author of the study in the Jan. 25  Archives of Internal Medicine, and an associate professor of medicine at Duke. If people have high blood pressure and a weight problem, a low-carbohydrate diet might be a better option than a weight-loss medication. Its important to know you can try a diet instead of medication and get the same weight-loss results with fewer costs and potentially fewer side effects.

Previous studies indicated that a low-carbohydrate diet and prescription-strength orlistat combined with a low-fat diet are effective weight-loss therapies; however, the two strategies had not been compared, an important omission now that orlistat is available over-the-counter.

The 146 overweight participants in the year-long study had a range of health problems typically associated with obesity, including diabetes, high blood pressure, high cholesterol and arthritis. The average weight loss for both groups was nearly 10 percent of their body weight.

"Not many studies are able to achieve that," said Yancy, who attributed the significant weight loss to the group counseling that was offered for 48 weeks. People tolerated orlistat better than I expected. Orlistat use is often limited by gastrointestinal side effects, but these can be avoided, or at least lessened, by following a low-fat diet closely. We counseled people on orlistat in our study fairly extensively about the low-fat diet.

In addition to achieving equal success at weight loss, the methods proved equally effective at improving cholesterol and glucose levels. Yancy said it was the difference in blood pressure results that was most surprising. Nearly half (47 percent) of patients in the low-carbohydrate group had their blood pressure medication decreased or discontinued while only 21 percent of the orlistat plus low-fat diet group experienced a reduction in medication use. Systolic blood pressure dropped considerably in the low-carbohydrate group when compared to the orlistat plus low-fat diet group.

"I expected the weight loss to be considerable with both therapies, but we were surprised to see blood pressure improve so much more with the low-carbohydrate diet than with orlistat," Yancy said. "While weight loss typically induces improvements in blood pressure, it may be that the low-carbohydrate diet has an additional effect."