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

Abstract

Background: Peptides derived from food proteins have in clinical trials shown an effect on blood pressure. Their biological mechanism is mainly due to inhibition of angiotensin-I-converting enzyme (ACE) and thereby regulation of 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 was included in meta-analysis and their pooled effect was estimated with a random effects model. Results: Pooled effect by peptides was for systolic blood pressure –5.13 mmHg (95% CI -7.12, -3.14) and for diastolic blood pressure -2.42 mmHg (95% CI -3.82, -1.03). There were indications of publication bias for diastolic blood pressure data. Conclusions: Peptides derived from food proteins can give a significant reduced blood pressure and could therefore be a supplement or alternative to pharmaceutical treatment of mild hypertension. Their effect seems more pronounced than, or at least comparable to that of other food components studied by randomised controlled trials. A high proportion of the reported trials were done using the well-known ACE inhibiting tripeptides Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP).

Key words: angiotensin-I-converting enzyme (ACE), hypertension, clinical trials

(Published online: 18 January, 2008)

Citation: Food & Nutrition Research, Vol. 52, 2008. DOI: 10.3402/fnr.v52i0.1641