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), thereby regulating blood pressure through the renin-angiotensin system. A meta-analysis of these trials is needed to better 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 food proteins and their effect on blood pressure. DESIGN: Trials identified using a defined search strategy in PubMed were included in the meta-analysis, and their 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 publication bias for diastolic blood pressure data. CONCLUSIONS: Peptides derived from food proteins may lead to significantly reduced blood pressure and could therefore be a supplement or alternative to pharmaceutical treatment for mild hypertension. Their effect seems more pronounced, or at least comparable, to that of other food components studied by randomized controlled trials. A high proportion of the reported trials was carried out using the well-known ACE inhibiting tripeptides – Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP).