Replace Nuts for Carbs Beneficial in Diabetes

David J. A. Jenkins, MD, from the Clinical Nutrition and Risk Factor Modification Center at St. Michael's Hospital Toronto in Ontario, Canada, writes, "Fat intake, especially monounsaturated fatty acid (MUFA), has been liberalized in diabetic diets to preserve HDL [high-density lipoprotein] cholesterol and improve glycemic control, yet the exact sources have not been clearly defined."  "Therefore, we assessed the effect of mixed nut consumption as a source of vegetable fat on serum lipids and HbA1c  in type 2 diabetes."

Jenkins and his colleagues provided three different diet supplements to subjects with Type 2 diabetes. One group was given muffins, one was provided with a mixture of nuts including raw almonds, pistachios, walnuts, pecans, hazelnuts, peanuts, cashews, and macadamias, and one group was given a mixture of muffins and nuts.

Subjects receiving the nut-only supplement reported the greatest improvement in blood glucose control using the glycosylated hemoglobin (HbA1c) test. The nut diet subjects also experienced a reduction in low-density lipoprotein cholesterol (known as LDL, or "bad cholesterol"). The subjects provided the muffin supplement or mixed muffin-and-nut supplement experienced no significant improvement in gylcemic control but those receiving the muffin-nut mixture also significantly lowered their serum LDL levels.

"Those receiving the full dose of nuts reduced their HbA1c by two-thirds of what the U.S. Food and Drug Administration recognizes as being clinically meaningful for therapeutic agents. Furthermore, neither in the current study nor in previous reports has nut consumption been associated with weight gain. If anything, nuts appear to be well suited as part of weight-reducing diets," Dr. Jenkins said.

"The study indicates that nuts can provide a specific food option for people with Type 2 diabetes wishing to reduce their carbohydrate intake."

"Two ounces of nuts daily as a replacement for carbohydrate foods improved both glycemic control and serum lipids in type 2 diabetes," the study authors write.

"Nut consumption not only improved glycemic control but also lipid risk factors for [coronary heart disease]," the study authors conclude. "We have no explanation for the lack of antioxidant effects of nuts seen with previous studies but may relate to antioxidants in wheat bran and apple concentrate used in the muffins. We conclude that mixed, unsalted, raw, or dry-roasted nuts have benefits for both blood glucose control and blood lipids and may be used to increase vegetable oil and protein intake in the diets of type 2 diabetic patients as part of a strategy to improve diabetes control without weight gain."

Diabetes Care, Online June 29, 2011