Study: Can a Plant-Based Diet Prevent Type 2 Diabetes?

Adhering to a plant-based diet may help prevent type 2 diabetes, according to a study published in JAMA Internal Medicine.

In this study, researchers performed a systematic search of PubMed, MEDLINE, Embase, Web of Science, as well as reference lists using search terms that included “plant-based diet”, “vegetarian”, “vegan”, and “type 2 diabetes.” The search was conducted through February 15, 2019. They examined any prospective observational studies that explored the correlation between adherence to a plant-based diet and type 2 diabetes among adults 18 years or older. Exclusion criteria was stipulated as any study that exclusively reported cross-sectional associations or reported outcomes of type 1 or gestational diabetes. The researchers used a National Heart, Lung, and Blood Institute assessment tool to evaluate study quality while implementing the random-effects method to calculate relative risk (RR) and 95% confidence intervals (CIs). Overall, the researchers identified nine studies which totaled over 300,000 participants. They conducted data analysis between December 2018 and February 2019.

The Efficacy of Plant-Based Eating

According to the results of the study, a significant association was found between higher adherence to a plant-based dietary pattern and risk of type 2 diabetes (RR=0.77; 95% CI, 0.71 to 0.84) when juxtaposed with less adherence, with modest diversity across studies (I2 = 44.5%; P = .07 for heterogeneity). The results found similar findings when using the fixed-effects model (RR=0.80; 95% CI, 0.75 to 0.84). Consistent associations were observed across predefined subgroups. This linked was strengthened when healthy plant-based foods, such as fruits, vegetables, whole grains, legumes, and nuts, were included in the definition of plant-based patterns (RR, 0.70; 95% CI, 0.62-0.79). Moreover, most studies were deemed robust with respect to dietary assessment, disease outcomes, and statistical adjustment for confounding factors. Overall, the findings were broadly consistent in several prespecified subgroups and across sensitivity analyses.

“Our findings suggest that plant-based dietary patterns were associated with lower risk of type 2 diabetes, even after adjustment for BMI. Owing to the overall low feasibility of randomized clinical trials directly testing plant-based dietary patterns for the prevention of type 2 diabetes, our study provides important supporting evidence in conjunction with randomized clinical trials on intermediate end points to suggest a possible protective role of these dietary patterns against the development of type 2 diabetes,” the study authors wrote.

In summation, they noted that “further experimental evidence could help provide insights into other novel pathways that could mediate the beneficial association between plant-based dietary patterns and type 2 diabetes.”