Can a vegan diet improve diabetes?

This review looked at whether a vegan diet can improve type 2 diabetes (T2D). It found that a vegan diet can lower glucose (sugar) levels for people with T2D.

Vegan diets have become more popular, for both health and ethical reasons. A vegan diet includes plant-based foods and avoids meat, eggs, or dairy. But can a vegan diet improve T2D? For people with T2D, the body does not respond well to the hormone insulin, which controls the amount of glucose (sugar) in the blood. Glucose is absorbed from the gut into the bloodstream after eating carbohydrates such as sugar or pasta. However, fiber slows down digestion and the absorption of glucose into the blood. Fiber can improve fullness and aid in weight management. Fiber also improves the microbiome (friendly bacteria). The microbiome plays an important role in the hormonal system, including hunger.

Vegan diets tend to be high in fiber and low in fat and protein. Because it is typically low-calorie, a vegan diet can aid in weight management. T2D is linked to obesity, and losing or managing weight is an important aspect of diabetes care. However, it is not clear whether a vegan diet can improve blood glucose control for people with T2D.

This review included 8 studies looking at the effect of a vegan diet on people with T2D. Half of the people were assigned a vegan diet. The other half ate their usual diet, a conventional diabetes diet, or a portion-control diet. Patients were followed for between 6 and 74 weeks depending on the study.

Glycated hemoglobin (HbA1c) is a measure of blood glucose control over the previous two to three months. Of the eight trials, five studies found that HbA1c significantly improved on a vegan diet (reduction of 0.3% to 1.4%). Three of the studies found that the comparison diet also significantly improved HbA1c.

All five of the studies which measured body weight found that people with T2D lost significant weight while eating a vegan diet. Two studies found that the comparison diet also led to significant weight loss.

Low-density lipoprotein (LDL) cholesterol, also known as “bad” cholesterol, can clog the arteries and increase the risk of heart disease. Three studies found that a vegan diet significantly improved LDL cholesterol. Two studies found that the comparison diet also significantly improved LDL.

This review found that a vegan diet can improve blood glucose control, body weight, and cholesterol for people with T2D.

This review did not combine data from the different studies. Additional reviews are needed.

Talk to your doctor or nutritionist about the right diet for you. It is more difficult to get certain nutrients including vitamin B-12 from a vegan diet, so a supplement or multivitamin may be needed on this diet.