Milk Peptides Lower Blood Pressure by Up to 10 mmHg in Placebo-Controlled Trial

Single-blind, placebo-controlled trial. 131 volunteers with high-normal blood pressure or mild hypertension were randomized to four groups of 32–33 people. Each received two tablets daily containing either placebo or one of three doses of casein hydrolysate (VPP+IPP at 1.8, 2.5, or 3.6 mg). Blood pressure was measured at baseline, 3 weeks, and 6 weeks. The casein hydrolysate was prepared using Aspergillus oryzae protease.

A 10 mmHg reduction in systolic blood pressure from a food-derived peptide is clinically meaningful — comparable to some blood pressure medications. These lactotripeptides (VPP and IPP) work by the same mechanism as ACE inhibitor drugs (enalapril, lisinopril) but come from fermented milk protein. This study helped establish the scientific basis for functional food products marketed for blood pressure management.

This study is part of a body of research that led to the commercialization of VPP/IPP-containing functional foods and supplements for blood pressure management, particularly popular in Japan and Europe. The lactotripeptides have been the subject of meta-analyses and regulatory reviews. While the effects are modest compared to prescription drugs, they represent a bridge between dietary intervention and pharmacotherapy for people with borderline high blood pressure.

Single-blind design (only participants blinded, not researchers) introduces potential bias. Relatively small groups (32–33 per arm). Only systolic BP was affected — no diastolic reduction. The 6-week duration doesn't capture long-term effects or safety. The study doesn't compare to standard antihypertensive medications. Japanese study population may limit generalizability.