Abstract 5138: Effect of Dietary Protein Supplementation on Blood Pressure: A Randomized Controlled Trial
Background: Observational studies have reported an inverse association between dietary protein intake and blood pressure (BP). We compared the effect of soy protein and milk protein supplementation on BP among healthy adults.
Methods: We conducted a randomized, double-blind, 3-phase crossover trial among 362 participants aged 22 years and older with prehypertension or stage-1 hypertension. The trial participants were assigned to take 40 grams/day of soy protein, milk protein, or complex carbohydrate supplementation for 8 weeks in a random order. A 3-week washout period was implemented between the interventions. Three BPs were measured at 2 baseline and 2 termination visits during each intervention phase using a random-zero sphygmomanometer.
Results: Baseline mean age was 48.0 years, body mass index 29.2 kg/m2, systolic BP 126.7 mmHg and diastolic BP 82.4 mmHg. Over 57.0% of participants were male, 34.3% were black, 89.0% had a college education, 7.3% were current smokers, and 44% consumed alcohol. Compared to carbohydrate, both soy and milk protein intake significantly reduced systolic BP (see table⇓). Diastolic BP was also reduced but this change did not reach the customary level of statistical significance. There was no significant difference between the BP reductions achieved with soy or milk protein supplementation.
Conclusion: This randomized controlled trial indicates that both soy and milk protein intake reduce BP among patients with prehypertension and stage-1 hypertension. Furthermore, it suggests an increase of dietary protein intake should be part of nutrition intervention for the prevention and treatment of hypertension.