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Review
. 2022 Mar 10;10(6):1950-1960.
doi: 10.1002/fsn3.2811. eCollection 2022 Jun.

Consumption of whole grains and risk of type 2 diabetes: A comprehensive systematic review and dose-response meta-analysis of prospective cohort studies

Faezeh Ghanbari-Gohari  1 , Seyed Mohammad Mousavi  1   2 , Ahmad Esmaillzadeh  1   2   3
Affiliations
Review

Consumption of whole grains and risk of type 2 diabetes: A comprehensive systematic review and dose-response meta-analysis of prospective cohort studies

Faezeh Ghanbari-Gohari et al. Food Sci Nutr. .

Abstract

This study aimed to quantitatively summarize earlier findings on the association between whole grain (WG) intake and type 2 diabetes (T2D) risk. We searched related keywords on PubMed/Medline, Scopus, and Google Scholar up to October 2021. Prospective observational studies investigating the association between WG intake and risk of T2D were included. The random-effects model calculates the summary relative risks by contrasting categories and linear and nonlinear dose-response associations. Eleven prospective cohort studies, including 463,282 participants and 37,249 type 2 diabetes incidents, were analyzed. The pooled relative risk (RR) for the highest versus the lowest WG intake category indicated a 21% decrease in T2D risk (95% confidence interval (CI): 0.73-0.85, I 2 = 77%). Each additional 50 grams WG consumption per day was associated with a 23% reduced risk of T2D. The nonlinear association of WG and T2D revealed that 60 grams WG intake per day would give the highest benefit to prevent T2D (Pnonlinearity < 0.001). The findings were not affected by any individual study. No evidence of publication bias was documented. In conclusion, a high intake of WG was associated with a lower risk of T2D. Randomized controlled trials are needed to confirm our results.

Keywords: diabetes mellitus; meta‐analysis; systematic review; whole grain.

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Conflict of interest statement

The authors declare that they do not have any conflict of interest.

Figures

FIGURE 1
FIGURE 1
Flowchart of the number of studies identified and selected into the meta‐analysis
FIGURE 2
FIGURE 2
Relative risk and 95% confidence intervals (CIs) of type 2 diabetes for the highest compared to the lowest category of whole grain consumption. The black square and horizontal line represent the study‐specific HR and 95% CI, respectively; the area of the black square is proportional to the specific‐study weight to the overall meta‐analysis. The center of the open diamond presents the pooled HR and its width represents the pooled 95% CI. Weights are from random‐effects analysis
FIGURE 3
FIGURE 3
Dose–response analysis of risk of type 2 diabetes and whole grain consumption. The solid line and the long‐dashed line represent the estimated HR and its 95%CI; the solid line represents the linear relation
See this image and copyright information in PMC

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