Effects of Whole Grain Intake, Compared to Refined Grain, on Glycemia and Insulinemia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Year: 2021
Type: review
Study designs: Systematic Review, Meta-Analysis
Abstract: Epidemiological study results suggest that whole grain (WG) consumption is associated with a reduced risk of type 2 diabetes; however, the potential mechanism behind this observation is unclear. WG intake may lower postprandial glycemia and insulinemia and improve insulin sensitivity, thereby contributing to a reduced risk of type 2 diabetes. The objective of this systematic review and meta-analysis was to evaluate the impact of WG on postprandial glycemia and insulinemia and markers of glycemic control and insulin sensitivity/resistance. A systematic review and meta-analysis was conducted on randomized controlled trials (RCTs) evaluating the effect of WG intake, compared to refined grain (RG) intake, on postprandial glycemia and insulinemia area under the curve and markers of glycemic control and insulin sensitivity/resistance in adults. A search of PubMed and Scopus yielded 80 relevant RCTs. Pooled estimates were expressed as standardized mean differences (SMD) between the WG intervention and RG control group. WG intake resulted in a significant reduction of postprandial glycemia (SMD: −0.46, 95% CI: −0.59, −0.33, P < 0.001) and insulinemia (SMD: −0.29, 95% CI: −0.39, −0.20, P < 0.001), compared to RG intake. There were no significant effects of WG on fasting glucose, fasting insulin, or homeostatic model assessment of insulin resistance (HOMA-IR); however, there was a marginally significant benefit of WG intake for glycated hemoglobin (HbA1c) (P = 0.050). Compared to RG foods, WG foods improve postprandial glycemia and insulinemia which may partially explain the association of WG intake and reduced risk of type 2 diabetes. However, WG intake did not impact long-term markers of glycemic and insulinemic control, except for a marginally significant effect on HbA1c. While short term improvements in glycemic response may be beneficial, more investigations are needed to determine if these lead to long-term benefits in reducing the risk of type 2 diabetes. PROSPERO Registration: CRD42020180069 This research was funded by General Mills, Inc.
Institutions: General Mills (United States), Indiana University
Language: English
Subfield: Nutrition and Dietetics
Field: Nursing
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,630
OpenAlex ID: W3168891624