According to a new study from Harvard T.H. Chan School of Public Health, eating a plant-based diet (rich in high-quality plant foods such as whole grains, fruits, vegetables, nuts, and legumes) is linked with a substantially lower risk of developing type 2 diabetes.
“This study highlights that even moderate dietary changes in the direction of a healthful plant-based diet can play a significant role in the prevention of type 2 diabetes,” said Ambika Satija, a postdoctoral in the Department of Nutrition, and lead author of the study. “These findings provide further evidence to support current dietary recommendations for chronic disease prevention.”
The study was published online June 14, 2016 in PLOS Medicine.
While previous studies have found links between vegetarian diets and improved health outcomes, including reduced risk of type 2 diabetes, this new study is the first to make distinctions between healthy plant-based diets and less healthy ones that include things like sweetened foods and beverages, which may be detrimental for health.
The researchers followed more than 200,000 male and female health professionals across the U.S. for more than 20 years who had regularly filled out questionnaires on their diet, lifestyle, medical history, and new disease diagnoses as part of three long-term studies.
The study found that people who devoted themselves to a plant-based diet saw a 20% reduction in their risk of type 2 diabetes. Eating a healthy version of a plant-based diet was linked with a 34% lower diabetes risk, while a less healthy version (foods such as refined grains, potatoes, and sugar-sweetened beverages) was linked with a 16% increased risk.
Even slightly lowering animal food consumption, from 5-6 servings per day to about 4 servings per day–was linked with lower diabetes incidence, the study found.
“A shift to a dietary pattern higher in healthful plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in animal-based foods, especially red and processed meats, can confer substantial health benefits in reducing risk of type 2 diabetes,” said Frank Hu, professor of nutrition and epidemiology at Harvard Chan School and senior author of the study.
The researchers suggested that healthful plant-based diets could be lowering type 2 diabetes risk because such diets are high in fiber, antioxidants, unsaturated fatty acids, and micronutrients such as magnesium, and are low in saturated fat. In addition, healthy plant foods may also be contributing to a healthy gut microbiome.