Meta-Analysis: Adherence to Plant-Based Diet May Lower Risk for Type 2 Diabetes

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Plant-based dietary patterns are associated with lower risk for type 2 diabetes.

Plant-based dietary patterns are associated with lower risk for type 2 diabetes (T2D), especially when enriched with fruits, vegetables, and other healthy foods, according to study results published in JAMA Internal Medicine.

To determine whether a plant-based diet is beneficial in the primary prevention of T2D, researchers conducted a systematic review and meta-analysis of 9 prospective cohorts from 7 publications including 307,099 participants (range for mean age at baseline, 36.0-64.6 years) with 23,544 cases of incident T2D. Included studies assessed diet using common food frequency questionnaires and followed patients for self-reported and validated T2D incidence. Studies ranged in duration from 2 to 28 years of follow-up.

In a dose-response meta-analysis, the researchers discovered a significant inverse linear relationship between greater adherence to a plant-based diet and T2D risk when compared with poorer adherence (relative risk [RR], 0.77; 95% CI, 0.71-0.84; I2 =44.5%; P =.07 for heterogeneity). This was similarly true for an inverse-variance fixed-effects model, which resulted in a pooled RR of 0.80 (95% CI, 0.75-0.84). Predefined subgroups (region, age, sex, and dietary classification) yielded consistent associations between plant-based diets and lower T2D risk (range for pooled RRs, 0.64-0.84).

The observed association was found to be strongest when the definition of plant-based patterns encompassed only healthy plant-based foods such as fruits, vegetables, legumes, nuts, and whole grains (RR, 0.70).

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Several limitations were noted for this study, including possible misclassification of dietary exposures because of the self-reported nature of food frequency questionnaires.

“[O]ur study provides important supporting evidence in conjunction with randomized clinical trials…to suggest a possible protective role of these dietary patterns against the development of T2D,” said the reviewers. “Further experimental evidence could help provide insights into other novel pathways that could mediate the beneficial association between plant-based dietary patterns and T2D.”

Disclosure: Several study authors declared affiliations with industry partners. Please see the original reference for a full list of authors’ disclosures.

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Qian F, Liu G, Hu FB, Bhupathiraju SN, Sun Q. Association between plant-based dietary patterns and risk of type 2 diabetes: a systematic review and meta-analysis [published online July 22, 2019]. JAMA Intern Med. doi:10.1001/jamainternmed.2019.2195