Including walnuts in a low-fat/modified-fat diet improves HDL cholesterol-to-total cholesterol ratios in patients with type 2 diabetes.
OBJECTIVE
The aim of this study was to examine the effect of a moderate-fat diet inclusive of walnuts on blood lipid profiles in patients with type 2 diabetes.


METHODS
This was a parallel randomized controlled trial comparing 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. Fifty-eight men and women, mean age 59.3 +/- 8.1 years, started the trial. Dietary advice was given at baseline with monthly follow-up and fortnightly phone calls for support. Body weight, percent body fat, blood lipids, HbA1c, total antioxidant capacity, and erythrocyte fatty acid levels were measured at 0, 3, and 6 months. Data were assessed by repeated-measures ANOVA with an intention-to-treat model.


RESULTS
The walnut group achieved a significantly greater increase in HDL cholesterol-to-total cholesterol ratio (P=0.049) and HDL (P=0.046) than the two other treatment groups. A 10% reduction in LDL cholesterol was also achieved in the walnut group, reflecting a significant effect by group (P=0.032) and time (P=0.036). There were no significant differences between groups for changes in body weight, percent body fat, total antioxidant capacity, or HbA1c levels. The higher dietary polyunsaturated fat-to-saturated fat ratio and intakes of omega-3 fatty acids in the walnut group were confirmed by erythrocyte biomarkers of dietary intake.


CONCLUSIONS
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.
Tapsell
Linda C
LC
National Centre of Excellence in Functional Foods, Northfields Avenue, University of Wollongong, NSW 2522, Australia. ltapsell@uow.edu.au
Gillen
Lynda J
LJ
Patch
Craig S
CS
Batterham
Marijka
M
Owen
Alice
A
Baré
Marian
M
Kennedy
Meredith
M
D015415:Biomarkers / Q000097:blood; D001835:Body Weight; D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D018752:Diet, Fat-Restricted; D002149:Energy Intake; D015525:Fatty Acids, Omega-3; D005260:Female; D006801:Humans; D031324:Juglans; D008297:Male; D008875:Middle Aged; D009754:Nuts; D009765:Obesity / Q000178:diet therapy*
D015415:Biomarkers; D008076:Cholesterol, HDL; D015525:Fatty Acids, Omega-3; D002784:Cholesterol