Effect of peptides derived from food proteins on blood pressure: a meta-analysis of randomized controlled trials

Background: In clinical trials, peptides derived from food proteins have shown an effect on blood pressure.This biological mechanism is mainly due to inhibition of angiotensin-I-converting enzyme (ACE), therebyregulating blood pressure through the renin-angiotensin system. A meta-analysis of these trials is needed tobetter quantify their effect, sources of variation, and possible publication bias.Objective: To perform a meta-analysis of placebo-controlled clinical trials on peptides derived from foodproteins and their effect on blood pressure.Design: Trials identified using a defined search strategy in PubMed were included in the meta-analysis, andtheir pooled effect was estimated with a random effects model.Results: Pooled effect of peptides was - 5.13 mmHg (95% CI: - 7.12, - 3.14) for systolic blood pressure,and - 2.42 mmHg (95% CI: - 3.82, - 1.03) for diastolic blood pressure. There were indications of publicationbias for diastolic blood pressure data.Conclusions: Peptides derived from food proteins may lead to significantly reduced blood pressure and couldtherefore be a supplement or alternative to pharmaceutical treatment for mild hypertension. Their effectseems more pronounced, or at least comparable, to that of other food components studied by randomizedcontrolled trials. A high proportion of the reported trials was carried out using the well-known ACEinhibiting tripeptides - Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP).