Healthnotes Newswire (October 19, 2006)—A low-fat vegan (animal-free) diet appears to be healthful for people with diabetes—even more so than the diet recommended by the American Diabetes Association (ADA), a new study finds.

Type 2 diabetes (adult-onset diabetes) is one of the fastest growing chronic diseases in the developed world. A family history of diabetes and obesity are important risk factors for this disease, in which the body doesn’t properly respond to insulin, resulting in too much blood sugar (glucose).

Over time, high circulating levels of glucose and insulin cause irreversible damage to many tissues. Blood glucose testing indicates the level at a single moment in time. A test known as hemoglobin A1c (HgbA1c) measures the glucose deposited on the red blood cells and is considered an accurate reflection of long-term glucose control as well as a good predictor of the risk for long-term diabetes complications.

The number of people being diagnosed with type 2 diabetes is growing every year, but diabetes remains relatively uncommon among people who eat a plant-based diet. Some studies have found that a combination of exercise and vegetarian diet improves blood glucose levels in people with diabetes, but the relationship between vegetarian diet alone and blood glucose control has not previously been studied.

In the new study, published in Diabetes Care, 99 people with diabetes were randomly assigned to eat a low-fat vegan diet or a diet based on ADA guidelines for 22 weeks. The vegan diet consisted of vegetables, fruits, grains, and legumes, and the calories from fat were kept at 10% or less, but portion sizes and total calorie intake were unrestricted. The goals of the ADA diet, by contrast, were to keep the saturated fat calories to 7% or less, cholesterol intake to no more than 200 mg per day, and total calories restricted to promote weight loss.

Improved blood glucose control, indicated by a drop in HgbA1c, was noted in both groups and was closely linked to weight loss. The people in the low-fat vegan diet group, however, lost more weight and experienced nearly twice the drop in HgbA1c as those in the ADA diet group. The low-fat vegan diet was also associated with greater improvements in cholesterol levels than the ADA diet.

“A low-fat, plant-based diet influences nutrient intake and body composition in several ways that may, in turn, affect insulin sensitivity,” the researchers note in their conclusion. “Our data suggest that the weight-reducing effect of the vegan diet is responsible for a substantial portion of its effect on [Hgb]A1c.”

“A healthy, balanced diet that provides adequate carbohydrates for energy and adequate protein for tissue maintenance is an essential component of diabetes management,” said Mary Wood, a clinical nurse who specializes in diabetes education. She added, “The goals of treating type 2 diabetes include achieving and sustaining a healthy weight and consistent near-normal glucose levels. In this study, the weight loss, which was greater in the vegan diet group, was responsible for the majority of the improvement in glycemic control. Weight control happens more easily when people eat low fat (less calorie-dense) and high fiber foods (more filling). The omission of a large food group, such as animal products in the vegan diet group, makes following a weight-loss program easier, as well.”

Wood added that, while only a small percentage of Americans follow a vegan diet, this study does point out the benefits of a diet plentiful in fruits, vegetables, and whole grains.

(Diabetes Care 2006;29:1777–83)