The Impact of Whole Grains Consumption on Metabolic Health: An Umbrella Review of Systematic Reviews and Meta-Analyses of Randomized Controlled Trials

Abstract

Background: Growing randomized controlled trials (RCTs) have demonstrated that consumption of whole grains (WGs) can significantly improve metabolic health outcomes, including glycemic control, insulin sensitivity, and body weight management. The study aims to demonstrate the association between the consumption of WGs and metabolic health by analyzing and synthesizing the existing evidence. Methods: Five databases (PubMed, Web of Science, Embase, Scopus, and Cochrane Library) were systematically searched from their inception to March 27, 2025 to identify relevant systematic reviews and meta-analyses of RCTs investigating the association between WGs consumption and metabolic health in humans. Results: A total of 25 eligible publications were included, covering 113 outcomes. A wide range of outcomes were investigated, including diabetes-related outcomes (43%), lipid metabolism (21%), anthropometric measures (12%), appetite and energy intake (5%), blood pressure (9%) and inflammatory markers (10%). Our findings demonstrated that WGs consumption plays a crucial role in improving key aspects of metabolic health. Specifically, it is effective in managing diabetes, hyperlipidemia, hypertension, obesity, and inflammation, and it also notably improves appetite. Conclusions: Increasing whole grain consumption may do more good than harm for metabolic health, particularly diabetes and cardiovascular health. Further high-quality studies in different countries are needed to confirm these findings.