Improving the Diabetic Diet

December 23, 2008
Shivani Parmar, MPH

New evidence suggests that it may be time to rethink the suggested diabetic diet.

New evidence suggests that it may be time to rethink the suggested diabetic diet. A study published in the most recent issue of the Journal of the American Medical Association shows that a diet with large amounts of low-glycemic foods “had greater improvement in glycemic control and risk factors for coronary heart disease than persons on a diet with an emphasis on high-cereal fiber.”

Conducted by David J. A. Jenkins, MD, and colleagues at St Michael’s Hospital and the University of Toronto, the study randomized 210 participants with type 2 diabetes to receive either high-cereal fiber or low-glycemic index diet treatments for six months. The low-glycemic index diet emphasized “beans, peas, lentils, nuts, pasta, rice boiled briefly and low-glycemic index breads (including pumpernickel, rye pita, and quinoa and flaxseed) and breakfast cereals (including large flake oatmeal and oat bran). In the high-cereal fiber diet, participants were advised to take the "brown" option (whole grain breads; whole grain breakfast cereals; brown rice; potatoes with skins; and whole wheat bread, crackers, and breakfast cereals). Three servings of fruit and five servings of vegetables were encouraged on both treatments.”

Results showed that “hemoglobin A1c (HbA1c; a substance of red blood cells tested to measure the blood glucose level) decreased by -0.50 percent absolute HbA1c units in the low-glycemic index diet compared with -0.18 percent absolute HbA1c units in the high-cereal fiber diet. Significant treatment effects were observed for high-density lipoprotein cholesterol (HDL-C) and the low-density lipoprotein cholesterol (LDL-C):HDL-C ratio. HDL-C increased in the low-glycemic index diet group by 1.7 mg/dL and decreased by -0.2 mg/dL in the high-cereal fiber diet group.”

Researchers found that the LDL-C:HDL-C ratio decreased more in the low-glycemic index diet group than in the high-cereal fiber diet.

"Lowering the glycemic index of the diet improved glycemic control and risk factors for coronary heart disease (CHD). These data have important implications for the treatment of diabetes where the goal has been tight glycemic control to avoid complications. The reduction in HbA1c was modest, but we think it has clinical relevance," concluded the authors. "Low-glycemic index diets may be useful as part of the strategy to improve glycemic control in patients with type 2 diabetes taking antihyperglycemic medications."