The use of soybean protein dietary supplements may help reduce high blood pressure, according to a report in the Annals of Internal Medicine.

Findings from epidemiologic studies have suggested that blood pressure drops as vegetable protein intake rises. However, the authors note, only a few clinical trials have looked at this association and most have suffered from design issues, such as not enough subjects or not using blood pressure change as the main outcome measure.

To address these problems, Dr. Jiang He, of Tulane University in New Orleans, and colleagues assessed blood pressure changes in 302 adults who were randomly selected to take soybean or inactive carbohydrate supplements for 12 weeks. All of the subjects had slightly high blood pressures.

Compared with subjects who received the carb supplements, soybean-supplemented subjects experienced a significant drop in blood pressure. The net change in blood pressure was most pronounced among subjects with blood pressures of at least 140/90.

These results, the authors conclude, “provide new evidence supporting dietary soybean protein supplementation to prevent and treat” high blood pressure.

In a related editorial, Drs. Jeffrey A. Cutler and Eva Obarzanek of the National Heart, Lung, and Blood Institute in Bethesda, Maryland, comment that the new study provides “another important link between blood pressure and dietary macronutrient intake,” but add that further studies are needed before soybean supplements can be recommended to patients with high blood pressure.

SOURCE: Annals of Internal Medicine, July 5, 2005.