according to a new systematic review and meta-analysis of nine observational studies.
The findings aren’t conclusive, but the study authors wrote in JAMA Internal Medicine that they suggest that “plant-based dietary patterns were associated with lower risk of type 2 diabetes, even after adjustment for [body mass index].”
According to 2015 figures provided by the American Diabetes Association, about 29 million people in the United States have type 2 diabetes. Overall, diabetes contributes to hundreds of thousands of deaths each year, which makes it the seventh-leading cause of death in the nation.
For the new analysis, researchers led by Frank Qian, MPH, of Harvard T.H. Chan School of Public Health included nine studies that examined diet and type 2 diabetes. In all, the studies included 307,099 participants, and there were 23,544 cases of incident type 2 diabetes. They were conducted in five countries, including the United States, and tracked participants for 2-28 years; the studies were all published within the last 11 years. The mean ages of participants ranged from 36-65 years.
The meta-analysis linked higher consumption of plant-based foods to a 23% reduced risk of type 2 diabetes, compared with lower consumption (relative risk, 0.77; 95% confidence interval, 0.71-0.84; P = .07 for heterogeneity). The risk dipped even further (down to 30%) when the researchers analyzed four studies that focused on healthy plant-based foods, such as fruits and vegetables, instead of foods such as refined grains, starches, and sugars (RR, 0.70; 95% CI, 0.62-0.79).
The researchers suggested that plant-based diets may lower the risk of diabetes type 2 by limiting weight gain. They also noted various limitations to their analysis, such as the reliance on self-reports and the observational nature of the studies.
Still, “in general populations that do not practice strict vegetarian or vegan diets, replacing animal products with healthful plant-based foods is likely to exert a significant reduction in the risk of diabetes,” the authors wrote.
The study was funded by the National Institutes of Health, and one author received support from the National Institute of Diabetes and Digestive and Kidney Diseases. The remaining authors reported no conflicts of interest withing the scope of this study.
SOURCE: Qian F et al. JAMA Internal Medicine. 2019 Jul 22. doi: 10.1001/jamainternmed.2019.2195.