Effect of peptides derived from food proteins on blood pressure: a metaanalysis of randomized controlled trials

Abstract

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).