Scientific Study

OBJECTIVE Fat intake; especially monounsaturated fatty acid (MUFA); has been liberalized in diabetic diets to preserve HDL 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 HbA(1c) in type 2 diabetes. RESEARCH DESIGN AND METHODS A total of 117 type 2 diabetic subjects were randomized to one of three treatments for 3 months. Supplements were provided at 475 kcal per 2;000-kcal diet as mixed nuts (75 g/day); muffins; or half portions of both. The primary outcome was change in HbA(1c). RESULTS The relative increase in MUFAs was 8.7% energy on the full-nut dose compared with muffins. Using an intention-to-treat analysis (n = 117); full-nut dose (mean intake 73 g/day) reduced HbA(1c) (-0.21% absolute HbA(1c) units; 95% CI -0.30 to -0.11; P < 0.001) with no change after half-nut dose or muffin. Full-nut dose was significantly different from half-nut dose (P = 0.004) and muffin (P = 0.001); but no difference was seen between half-nut dose and muffins. LDL cholesterol also decreased significantly after full-nut dose compared with muffin. The LDL cholesterol reduction after half-nut dose was intermediate and not significantly different from the other treatments. Apolipoprotein (apo) B and the apoB:apoA1 ratio behaved similarly. Nut intake related negatively to changes in HbA(1c) (r = -0.20; P = 0.033) and LDL cholesterol (r = -0.24; P = 0.011). CONCLUSIONS Two ounces of nuts daily as a replacement for carbohydrate foods improved both glycemic control and serum lipids in type 2 diabetes.