Adding walnuts to a low-fat diet improves lipid profile for patients with type 2 diabetes.
"Walnuts are distinguished from other nuts by virtue of their higher polyunsaturated fat content (and importantly their a-linolenic acid [ALA] content) combined with antioxidants in the form of ?-tocopherol," write Linda C. Tapsell, PhD, from the National Centre of Excellence in Functional Foods, University of Wollongong in New South Wales, Australia, and colleagues. "There are mechanistic explanations for the influence of dietary polyunsaturated fatty acid (PUFA) on insulin action and energy metabolism, and cohort studies of women in the U.S. have demonstrated a reduced risk of developing type 2 diabetes with dietary PUFA replacing trans or saturated fatty acids (SFAs)."
In this parallel design trial, 58 adults with type 2 diabetes were randomized to one of three dietary advice groups, each with 30% energy as fat: low fat, modified low fat, and modified low fat inclusive of 30 g of walnuts per day. Mean age was 59.3 ± 8.1 years.
Patients received dietary advice at baseline, with monthly follow-up and telephone calls bimonthly for support. All groups were advised to consume fish and five daily portions of fruits and vegetables. Body weight, percent body fat, blood lipids, glycosylated hemoglobin (HbA1c), total antioxidant capacity, and erythrocyte fatty acid levels were measured at baseline and at three and six months, and analysis was by intent-to-treat.
Erythrocyte biomarkers of dietary intake confirmed higher dietary polyunsaturated fat-to-saturated fat ratio and intakes of ?-3 fatty acids in the walnut group. Compared with the two other treatment groups, the walnut group had a significantly greater increase in high-density lipoprotein (HDL) cholesterol-to-total cholesterol ratio (P = .049) and in HDL (P = .046). The walnut group also had a 10% reduction in low-density lipoprotein (LDL) cholesterol, reflecting a significant effect by group (P = .03) and time (P = .04).
The three groups were similar in changes in body weight, percent body fat, total antioxidant capacity, and HbA1c levels.
"Structured ‘whole of diet’ advice that included 30 g of walnuts/day delivering substantial amounts of polyunsaturated fatty acid improved the lipid profile of patients with type 2 diabetes," the authors conclude.
Diabetes Care. 2004;27:2777-2783
DID YOU KNOW: New Link Between Gum and Cardiovascular Diseases: Virginia Commonwealth University researchers have found that changes in the plasma lipoprotein profile of patients with severe periodontitis — a condition characterized by chronic infection and inflammation of the gums – may contribute to these patients’ elevated risk for heart disease and stroke. Researchers found that patients with generalized aggressive periodontitis generally had elevated plasma levels of a particularly bad subclass of the low density lipoprotein (LDL) called small-dense LDL. The findings suggest that it may be beneficial to test periodontitis patients for changes in their plasma lipoprotein profiles, so that available medication can be taken if necessary. Journal of Lipid Research, Dec. 2005