There is increasing evidence that consuming whole grains may reduce the risk of several chronic diseases. The aim of the work of Chanson-Rolle et al (2015) was to analyze the available scientific evidence in order to help derive a quantitative recommendation for the daily consumption of whole grains. Eight studies were included in the meta-regression analysis. The meta-analysis showed a statistically significant inverse association between intake of whole grains and occurrence of T2D. This observation confirms the findings of previous systematic reviews and meta-analyses. More importantly, the current meta-regression model makes it possible to estimate the decrease in risk of T2D corresponding to various changes in whole grain intakes. 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).
Chanson-Rolle A., Meynier A., Aubin F., Lappi J., Poutanen P., Vinoy S., Braesco V. "Systematic Review and Meta-Analysis of Human Studies to Support a Quantitative Recommendation for Whole Grain Intake in Relation to Type 2 Diabetes". 2015. PLOS ONE. DOI: 10.1371/journal.pone.0131377