Soybean Protein Lowers Blood Pressure

Results from observational studies have suggested that soybean protein supplementation lowers blood pressure. Now, researchers in China have tested this hypothesis in a randomized, double-blind, multicenter trial. A total of 302 adults with systolic BPs of 130 mm Hg to 159 mm Hg, diastolic BPs of 80 mm Hg to 99 mm Hg, or both, who were not taking antihypertensive medications, were assigned to consume isolated soybean protein (40 g daily) or complex carbohydrate from wheat (40 g daily) in cookies for 12 weeks.

At follow-up, mean decreases from baseline BP were significantly greater in the soybean protein group than in the control group (systolic: –13.0 mm Hg vs. –8.7 mm Hg; diastolic: –5.4 mm Hg vs. –2.6 mm Hg). Differences between the treatment groups were significantly greater among patients with hypertension (systolic BP, 140 mm Hg; diastolic, 90 mm Hg, or both) than among those with lower BPs. Rates of adverse effects did not differ significantly between the groups.

Despite the promising results from this short-term study, widespread recommendations of soybean protein supplementation would be premature. Editorialists point out that we don’t know enough about feasibility and safety. Nonetheless, they suggest that the findings provide support for diets higher in total protein intake.

References:

He J et al. Effect of soybean protein on blood pressure: A randomized, controlled trial. Ann Intern Med 2005 Jul 5; 143:1-9.