Effect of whey protein on blood pressure in pre- and mildly hypertensive adults: A randomized controlled study

In China, the frequency of mild hypertension cases remains prevalently high. Meanwhile, diets containing functional ingredients that control blood pressure have received considerable attention. In this randomized, controlled intervention study, 65 participants were randomly assigned to consume 30 g of whey protein or maltodextrin daily for 12 weeks. Blood pressure, body composition, biochemical analysis in plasma, and flow-mediated dilation (FMD), an index for evaluating endothelial function, were measured. Finally, 54 participants (27 participants in each group) completed the study. At the end of the intervention, the average systolic blood pressure (SBP) was 129.5 ± 7.7 mmHg in the control group and 128.2 ± 6.9 mmHg in the whey protein group (p = 0.052). In the overweight and obese participants, the SBP was significantly lower in the whey protein group than in the control group (126.5 ± 6.9 mmHg vs. 128.8 ± 7.4 mmHg, p = 0.033), and body fat, fat percentage, and waist circumference significantly decreased in the whey protein group (p = 0.010, 0.016, 0.019, respectively). No difference was observed between the control and whey protein groups with regard to the changes in plasma lipids, inflammatory cytokines, antioxidative indexes, endothelium-1, nitric oxide, angiotensin II, and angiotensin-converting enzyme. The increase in FMD was significantly higher in the whey protein group than in the control group (5.2% vs. 0.3%, p = 0.040). In conclusion, whey protein significantly decreased SBP in pre- and mildly hypertensive adults, who are also overweight and obese. Whey protein also improved endothelial function. The lowering effect of blood pressure was probably related to body fat loss in these participants.