BackgroundDue to the increasing evidence of their health benefits, whole grains are recommended for consumption worldwide. Such recommendations are, however, rarely quantitative. Our aim was to perform a quantitative evaluation of the relationship between whole grain consumption and the occurrence of type 2 diabetes (T2D) to support a recommendation on the daily consumption of whole grains.Methods and FindingsWe conducted a systematic review by searching three bibliographic databases. We included human studies addressing the relationship between whole grain consumption and T2D occurrence, and providing quantitative information on daily intake of whole grains. A dose-response meta-regression analysis between whole grain intake and T2D occurrence was performed, using a hierarchical mixed least square linear regression model. Eight observational studies were included (all but one prospective), with a total of 15,573 cases of T2D among 316,051 participants. Quantitative meta-regression demonstrated a significant linear inverse relationship between whole grain intake and T2D occurrence (P<0.0001), with an overall absolute reduction of 0.3% in the T2D rate for each additional 10 g of whole grain ingredient consumed daily. The association persisted when adjusted on sex, age, country, study design, follow up duration, and mode of report of whole grain intakes (as foods or ingredients).ConclusionsThe meta-regression model made it possible to estimate the decrease in T2D risk corresponding to various changes in whole grain intakes, and the results contribute to setting up quantitative recommendations. For instance, consuming three servings of whole grain foods (45 g of whole grain ingredients) daily would induce a 20% relative reduction in the T2D risk as compared to consuming a half serving (7.5 g of whole grain ingredients). These results should be considered for future recommendations, by considering the actual whole grain intake of the concerned populations. The systematic review protocol was published on the PROSPERO register (CRD42013006925).

BackgroundThe lactotripeptides isoleucine–proline–proline (IPP) and valine–proline–proline (VPP) have been shown to decrease systolic blood pressure (SBP) in several populations, but the size of the effect varies among studies. We performed a meta-analysis including all published studies to evaluate the SBP-lowering effect of IPP/VPP in Japanese subjects more comprehensively.Methods and FindingsEligible randomized controlled trials were searched for within four bibliographic databases, including two Japanese ones. Eighteen studies (including a total of 1194 subjects) were included in the meta-analysis. A random effect model using the restricted maximum likelihood (REML) estimator was used for the analysis. The analysis showed that consumption of IPP/VPP induced a significant reduction in SBP as compared with placebo in Japanese subjects, with an estimated effect of -5.63 mm Hg (95% CI, -6.87 to -4.39, P<0.0001) and no evidence of publication bias. A significant heterogeneity between series was evident, which could be explained by a significant influence of the baseline blood pressure status of the subjects, the effect of IPP/VPP on SBP being stronger in hypertensive subjects (-8.35 mm Hg, P<0.0001) than in non-hypertensive subjects (-3.42mm Hg, P<0.0001). Furthermore, the effect of IPP/VPP on SBP remained significant when limiting the analysis to series that tested the usual doses of IPP/VPP consumed daily (below 5 mg/d), with estimated effects of -6.01 mm Hg in the overall population and -3.32 mm Hg in non-hypertensive subjects.ConclusionsResults from this meta-analysis show that IPP/VPP lactotripeptides can significantly reduce office SBP in Japanese subjects with or without overt hypertension, and for doses that can potentially be consumed as an everyday supplement. This suggests that these peptides could play a role in controlling blood pressure in Japanese subjects. The systematic review protocol was published on the PROSPERO register (CRD42014014322).

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Several studies have reported the ability of the lactotripeptides valine-prolineproline (VPP) and isoleucine-proline-proline (IPP) to lower systolic blood pressure (SBP), including in Japanese populations. But the magnitude of the reported changes differs across trials. Conclusions from a previous meta-analysis in Japanese subjects suggest that this may be due at least partly to differences in subjects' blood pressure (BP) status. Therefore, we decided to resume this analysis, focusing only on non-hypertensive subjects and including newly-published eligible studies, in order to further evaluate the SBPlowering effect of VPP/IPP and study the influence of the ingested dose, type of ingredient (enzymatic or fermented) and food product (drink or supplement). The systematic search of four databases (including two in Japanese) allowed to identify 11 relevant randomized-controlled trials (581 subjects), which were included in the meta-analysis. Results reported a significant decrease in SBP following VPP/IPP intake in non-hypertensive Japanese individuals, with an estimated effect-size of −3.44 mm Hg (95% CI, −4.53 to −2.34, P < 0.0001) as compared to placebo. There was no indication of heterogeneity or publication bias. Furthermore, the type of food product and ingredient did not influence the SBP-lowering effect, which was significant and How to cite this paper: Chanson-Rolle, A.,

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