Blood pressure lowering effect of lactotripeptides assumed as functional foods: a meta-analysis of current available clinical trials

The oral assumption of lactotripeptides Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP) as nutraceuticals or functional foods is supposed to improve blood pressure (BP) control by angiotensin-converting enzyme-inhibition. However, data derived from clinical trials have reached conflicting conclusions. To perform a meta-analysis of placebo-controlled clinical trials evaluating the anti-hypertensive effect of lactotripeptides assumed as nutraceuticals or functional foods. 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, weighting for the inverse of the variance. Heterogeneity, publication bias, subgroup and meta-regression analyses were performed. A total of 18 trials have been identified, the clinical data of which have been clearly reported. Pooled effect of peptides was a reduction of -3.73 mm Hg (95% CI: -6.70, -1.76) for systolic blood pressure (SBP) and 1.97 mm Hg (95% CI: -3.85, -0.64) for diastolic blood pressure (DBP). The effect was more evident in Asian patients (SBP = -6.93 mm Hg (95% CI: -10.95, -2.94); DBP = -3.98 mm Hg (95% CI: -5.38, -2.44)) than in Caucasian ones (SBP = -1.17 mm Hg (95% CI: -2.82, 0.72); DBP = -0.52 mm Hg (95% CI: -1.39, 0.13)), and apparently not related to age, baseline BP values, dose of lactotripeptides assumed or length of the treatment. VPP and IPP lactotripeptides assumed as functional foods may significantly reduce SBP particularly in Asian subjects. The relevance of this findings in other ethnicities or associated with different dietary pattern should to be further investigated. Journal of Human Hypertension (2011) 25, 425-436; doi:10.1038/jhh.2010.85; published online 2 September 2010