Milk and soy protein supplements may be better than carbs for lowering blood pressure

Strike another blow for refined carbs: A study released today finds that soy and milk protein supplements may be associated with lower blood pressure more than refined carbohydrate supplements.

The study, published online in Circulation: Journal of the American Heart Assn., put 352 adults who were at risk for high blood pressure or who had mild hypertension on various rounds of supplements. The participants were given 40 grams of powdered soy, milk or refined complex carb supplements daily for eight weeks, and had their blood pressure taken at various intervals during the trial. They were told to keep their calories the same, as well as their usual sodium consumption and amount they exercised.

Although none of the groups experienced a significant drop in diastolic blood pressure readings, there were differences in systolic readings. A systolic reading (the top number) measures the force put on the arteries when the heart contracts, pushing blood through the arteries. A diastolic reading (the bottom number) measures the force in the arteries between heart beats.

Those who took the milk protein supplement had an average 2.3-mmHg lower systolic blood pressure compared with when they had the carb supplement. And those who had the soy protein supplement saw an average 2-mmHg drop in systolic pressure compared with the carb supplement.

Blood pressure readings didn’t change substantially during the time the study participants took the carb supplement.

“Some previous observational research on eating carbohydrates inconsistently suggested that a high carbohydrate diet might help reduce blood pressure,” said the study’s lead author, Dr. Jiang He, in a news release. He, an epidemiologist at Tulane University School of Public Health and Tropical Medicine in New Orleans, added, “In contrast, our clinical trial directly compares soy protein with milk protein on blood pressure, and shows they both lower blood pressure better than carbohydrates.”