November 17/Journal of the American Academy of Physician Assistants  (JAAPA) -- Clinical question: In overweight patients with newly diagnosed type 2 diabetes, does a Mediterranean-style diet delay the need for antihyperglycemic treatment?

Bottom line: For patients with newly diagnosed diabetes, perhaps we need to pay attention to diet interventions before reaching for the prescription pad. A Mediterranean diet, consisting of grains, poultry, and fish, with a sizeable (>30%) proportion of fat, kept the hemoglobin A1C (Hb A1C) level below 7% in more than 50% of patients for four years after being diagnosed with type 2 diabetes, allowing them to avoid antihyperglycemic therapy. In comparison, a low-fat, higher-carbohydrate diet prevented drug therapy in only 30% of patients. Both diets restricted caloric intake, which is probably at least as important as the diet itself. Both groups received monthly counseling with a dietitian or nutritionist for one year and then every other month from then on, which is a much larger intervention than simply giving patients a diet handout and wishing them the best of luck.

Synopsis: The value of treatment for hyperglycemia in patients with type 2 diabetes continues to drop as more studies demonstrate a lack of benefit. Still, so-called quality and performance measures, as well as patient expectations, will prompt most clinicians to begin treatment, and avoidance of drug therapy can be considered a patient-oriented outcome. The 215 participants were overweight, had newly diagnosed type 2 diabetes, were not treated with medicines and had an Hb A1C of less than 11%. The patients were randomly assigned, using concealed allocation, to either a low-fat American Heart Association diet or a Mediterranean diet. This Mediterranean diet consisted of vegetables and whole grains, with poultry and fish instead of red meat, and no less than 30% fat, mostly from olive oil. Both groups had diets restricted to 1,500 calories per day for women and 1,800 calories per day for men. To implement these diets, patients in both groups met with dietitians monthly in the first year and bimonthly thereafter. Patients measured portion size and kept food diaries. After four years, 44% of patients in the Mediterranean diet group had at least two consecutive quarterly measured Hb A1C percentages of at least 7, which is the American Diabetes Association criterion for beginning drug therapy, compared with 70% of patients assigned to the low-fat diet (hazard ratio = 0.63; 95% CI, 0.51-0.86). Patients in this Mediterranean diet group also lost more weight. The study was performed in Italy, and the same adherence rates -- and benefits -- may not be seen in countries that are not in the heart of the Mediterranean.

Esposito K, Maiorino MI, Ciotola M, et al. "Effects of a Mediterranean-style Diet on the Need for Antihyperglycemic Drug Therapy in Patients with Newly Diagnosed Type 2 Diabetes." Ann Intern Med. 2009;151(5):306-314.

From the November 23, 2009, Prepared Foods E-dition