“We further showed that individuals who consumed a healthy version of the plant-based diet by emphasising the intake of fresh fruits, vegetables, whole grains, nuts and legumes, and minimising intake of sugar-sweetened beverages and refined carbohydrates, had a further 30 per cent reduction in their risk of developing type 2 diabetes,” he said. “I would describe these risk reductions as being quite significant.”
Globally, diabetes is on the rise, and the number of people with diabetes has climbed from 108 million in 1980 to 422 million in 2014, according to the World Health Organisation.
“Indeed, a vegetarian or other plant-based diets that are high in free sugars and refined carbohydrates is likely to increase risk of type 2 diabetes especially when associated with low levels of physical activity,” Tom Sanders, professor emeritus of nutrition and dietetics at King’s College London noted in a written statement distributed by the Science Media Centre in the UK. He was not involved in the new paper.
More than 30 million people in the United States, or about 1 in 10, have diabetes and up to 95 per cent of them have type 2 diabetes, according to the US Centers for Disease Control and Prevention.
The new paper involved reviewing nine previously published studies on plant-based eating habits and type 2 diabetes among adults. Those studies included a total of 23,544 cases of type 2 diabetes.After reviewing the data in those studies, the researchers found that a higher adherence to a plant-based diet was associated with a lower risk of type 2 diabetes — that was consistent across all age groups and despite a person’s body mass index (which is a person’s weight in kilograms divided by the square of their height in meters, and the measurement is used to screen for obesity). A BMI of 25 to 29.9 is considered overweight, and a BMI of 30 or greater is considered obese. Obesity is a risk factor for type 2 diabetes.
However, there were some limitations in the study, including that the dietary data was based on people self-reporting their eating habits, which poses a risk of bias. Also only an association between plant-based diets and lower diabetes risk was found. More research is needed to determine if a causal relationship indeed exists.
“The paper does support what has been reported before, that diets with high fibre content are associated with reduced risk of cardiovascular and metabolic diseases,” Alexandra Johnstone, a senior research fellow at the University of Aberdeen’s Rowett Institute of Nutrition and Health in Scotland, said in a written statement distributed by the Science Media Centre in the UK. She was not involved in the new paper.
“Future research needs to focus on what components of a plant-based diet are linked to preventative health effects,” she said in the statement.
The new paper relied on those previously published studies to define “plant-based diet” but in general, “there are many types of diets that can be regarded as a plant-based diet, ranging from the strict vegan diet, the vegetarian diets, to diets that emphasise the intake of plant-based foods but do not completely exclude animal product intake,” Harvard’s said.