A new study, published this week in PLOS Medicine, shows that a diet low in animal-based foods and high in plant-based foods substantially lowers the risk of type 2 diabetes. They also find that the quality of the plant-based diet plays a significant role.
It is common knowledge that eating fruits and vegetables is essential to maintain a healthy body.
It is also becoming clear, as research mounts, that a diet featuring fewer animal products is also a healthier option.
For instance, a study published in 2013 that followed almost 70,000 people concluded that a vegetarian diet lowered the risk of cancer.
Similarly, a study published in Nutrition, Metabolism and Cardiovascular Diseases in the same year followed more than 15,000 individuals and found that a vegetarian diet lessened the risk of diabetes.
As a final example, a meta-analysis of more than 250 studies, published in JAMA Internal Medicine in 2014, demonstrated that a vegetarian diet significantly reduces blood pressure.
Vegetarianism and diabetes
The latest study in this vein once again looked at the effect of a vegetarian diet on diabetes. However, this study also looked at the quality of the vegetarian diet.
They took into account whether the vegetarian diet was high in nutritious plant-based foods, such as whole grains, fresh fruits, and vegetables, and contrasted it with less healthy vegetarian diets that included items like refined grains, potatoes, and sweetened beverages.
The team, headed up by Ambika Satija, also collated information about the amount of animal-based foods that the participants consumed.
In all, the study used data from more than 20,000 male and female health professionals across the United States over a 20-year period. The participants filled out regular questionnaires covering diet, medical history, current diagnoses, and lifestyle.
To evaluate each individual's diet, the team used a plant-based diet index; animal-derived foods were given low scores, whereas plant-derived foods received higher scores.
The team found that a diet low in animal products, but high in plant products, reduced the risk of type 2 diabetes by 20 percent.
When the researchers split the plant-based diets into healthier and unhealthier versions, they found that it impacted heavily on the risk of type 2 diabetes. Healthy plant-based diets produced a 34 percent reduced risk of type 2 diabetes, and the less healthy plant-based diets were linked to a 16 percent increased risk of the condition.
This implies that abstaining from animal products is not sufficient to stave off type 2 diabetes. Simply skipping the unhealthier items is not enough; it is important to make sure that healthier plant-based food items are included in the diet.
"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."
Senior author Frank Hu, Harvard T.H. Chan School of Public Health
Small changes, large benefits
The team found that just a relatively modest drop in the consumption of animal-based products, from five to six servings down to four servings per day, reduced type 2 diabetes incidence.
A diet high in plant-based foods is thought to reduce type 2 diabetes risk thanks to their high levels of antioxidants, fiber, micronutrients - such as magnesium - and unsaturated fatty acids. The lower levels of saturated fats in plant-based foods might also play a role.
Additionally, the authors theorize that a vegetarian diet has a positive influence on the gut's microbiome, which could also help reduce type 2 diabetes.
Although the study used a large sample of participants, there are some limitations. The main issue is the use of self-reported dietary behavior. However, because the data was taken cumulatively over a number of years, the potential for error is minimized.
The researchers conclude that, as previously demonstrated, a diet with lower quantities of animal products is healthier than one with higher levels. But, they also show that the quality of the diet plays an important role.
Written by Tim Newman