Effect of dietary protein supplementation on blood pressure: a randomized, controlled trial.

Circulation
Q1
Aug 2011
Citations:87
Influential Citations:3
Interventional (Human) Studies
90
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Methods
Randomized, double-blind, crossover trial with three 8-week intervention phases among 352 adults aged 22+ with prehypertension or stage-1 hypertension (mean baseline BP ~126.7/82.4 mmHg; 18.5% hypertensive). Men and women recruited from New Orleans, LA and Jackson, MS; exclusion criteria included SBP ≥160 mmHg, DBP ≥95 mmHg, antihypertensive therapy, and major cardiovascular or renal disease; adherence assessed via packet counts and supplement returns.
Intervention
2-week run-in with 40 g/day complex carbohydrate; then three 8-week phases of 40 g/day soy protein, 40 g/day milk protein, and 40 g/day complex carbohydrate (placebo), with a 3-week washout between phases; supplements taken twice daily in water or juice; energy intake adjusted to maintain baseline intake; participants were instructed to maintain usual physical activity and sodium intake.
Results
Compared with carbohydrate control, soy protein and milk protein supplementation reduced systolic BP by 2.0 mmHg (95% CI −3.2 to −0.7; p=0.002) and 2.3 mmHg (−3.7 to −1.0; p=0.0007), respectively; diastolic BP changes were not significant; no significant difference between soy and milk protein. Conclusion: partially replacing carbohydrate with soy or milk protein lowers systolic BP in adults with prehypertension or stage-1 hypertension, supporting protein-containing dietary strategies to help prevent and manage hypertension.
Limitations
Relatively short duration of intervention phases (8 weeks each); use of a high-glycemic-index refined carbohydrate as control; no dose–response assessment; potential carryover effects despite washout; limited generalizability beyond prehypertension or stage-1 hypertension.

Abstract

BACKGROUND Observational studies have reported an inverse association between dietary protein intake and blood pressure (BP). We compared the effect of soy protein, milk protein, and carbohydrate supplementation on BP among healthy adults. METHODS ...