ORLANDO – Evidence increasingly supports plant-based nutrition for preventing diabetes or improving outcomes in those with diabetes.
The Adventist Health Study-2 (AHS-2), for example, demonstrated that a plant-based eating pattern – defined as ad libitum whole grains, legumes, fruits, and vegetables, and avoidance of all animal products, added oils, and high-fat foods – reduced the incidence of type 2 diabetes. The prospective cohort study involving more than 96,000 adults demonstrated that body mass index and the incidence of diabetes increased in tandem with the amount of animal products in the diet, according to Meghan Jardine, who reviewed the recent literature on plant-based nutrition in a poster presented at the annual meeting of the American Association of Diabetes Educators.
The prevalence of type 2 diabetes among nonvegetarians, semivegetarians, pescovegetarians, lacto-ovovegetarians, and vegans in that study was 7.6%, 6.1%, 4.9%, 3.2%, and 2.9%, respectively, and BMI for each of those groups was 28.8, 27.3, 26.3, 25.7, and 23.6 kg/m2, respectively, said Ms. Jardine, a registered and licensed dietician, certified diabetes educator, and diabetes education coordinator at Parkland Health and Hospital System, Dallas.
AHS-2 also demonstrated increased longevity in those who followed a plant-based eating pattern, with men living 9.5 years longer and women living 6.1 years longer than their meat-eating counterparts (JAMA 2013;173:1230-8).
In addition, a National Institutes of Health study demonstrated that a low-fat vegan diet led to significantly greater improvements in glycemic and lipid control than did a conventional diabetes diet in patients with type 2 diabetes.
Hemoglobin A1c levels in 49 patients on the low-fat vegan diet improved from 8.06 to 7.65 at 74 weeks, but while the levels in 50 patients on the conventional diabetes diet initially improved from 7.93 to about 7.7 at 11 weeks, at 74 weeks they had increased to 7.94 (Diabetes Care 2006;29:1777-83).
Among the other findings that Ms. Jardine mentioned were those from "a remarkable study" in which 17 of 21 patients with sharp, burning pain characteristic of distal polyneuropathy experienced complete pain relief after initiating a low-fat, high-fiber, vegan diet along with a daily 30-minute walk, and findings from several studies that have suggested that plant-based eating preserved renal function.
Moreover, a plant-based eating pattern has been shown to reverse coronary artery disease and improve magnesium intake (which reduces insulin resistance), and the high fiber intake associated with plant-based eating improves glucose control and decreases mortality from circulatory, digestive, and inflammatory disease, she said.
Two recent studies demonstrated that meat consumption substantially increases the risk of type 2 diabetes. Even just a half serving per day increase was associated with a 48% increase over 4 years in one study (JAMA Intern. Med. 2013;173:1328-35).
Ms. Jardine noted that the Academy of Nutrition and Dietetics position is that "appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate and may provide health benefits in the prevention and treatment of certain disease," and that such diets have been found to be "highly acceptable in diverse populations with various disease states" (Diabetes Educ. 2010:36:33-48).
She warned that patients with diabetes who are on medications and who begin to follow a plant-based eating pattern should be instructed about how to recognize and treat hypoglycemia, as adjustments to medications that lower glucose, blood pressure, and cholesterol may be needed.