Effect of Lactotripeptides (Isoleucine-Proline-Proline/Valine-Proline-Proline) on Blood Pressure and Arterial Stiffness Changes in Subjects with Suboptimal Blood Pressure Control and Metabolic Syndrome: A Double-Blind, Randomized, Crossover Clinical Trial

Background: Lactotripeptides (LTPs) have a mild antihypertensive effect in hypertensive subjects. The main aim of our clinical trial was to test if LTPs could have some influence on blood pressure (BP) and related hemodynamic parameters in a sample of outpatients affected by metabolic syndrome. Methods: A randomized, double-blind, placebo-controlled, crossover clinical trial was conducted in a group of 40 nonsmoking volunteers with metabolic syndrome. The treatment periods were 4 weeks long and were separated by a 4-week washout period. The dietary supplementation was made by daily administration of LTPs from casein, 10.2 mg/day, and compared with placebo. Results: During the LTP treatment, patients experienced a significant mean decrease in systolic BP (SBP; -3.4 +/- 4.4 mmHg, P = 0.041), diastolic BP (DBP; -3.1 +/- 3.2 mmHg, P = 0.049), and pulse wave velocity (PWV; -0.7 +/- 0.3 m/sec, P = 0.001). After LTP treatment, delta SBP, DBP, and PP were all significantly improved (P < 0.01 for all) compared with placebo. PWV also improved significantly after LTP treatment with respect to the end of the treatment with placebo (-0.8 +/- 0.4 vs. -0.1 +/- 0.3 m/sec, P = 0.009). The square root of the ratio of peak:baseline pulse volume during hyperemia (root V2/V1) improved after LTP treatment only (1.2 +/- 0.4 vs. 1.4 +/- 0.5, P = 0.04). Through the evaluation of the hemodynamic parameters that were measured by the 24-hr ambulatory monitoring, we observed that SBP, MBP, and the percentage of time with SBP over the normal were significantly reduced only after the LTP treatment (P < 0.05). These parameters were also significantly improved when compared with the ones measured after the placebo treatment (P < 0.05). Conclusion: In our trial, during LTP treatment, patients affected by metabolic syndrome experienced a mild but significant improvement in office and 24-hr BP, PWV, and endothelial function compared with placebo treatment.