The Resulting Variation in Nutrient Intake With the Inclusion of Walnuts in the Diets of Adults at Risk for Type 2 Diabetes: A Randomized,Controlled,Crossover Trial

Abstract

Purpose:

We previously demonstrated that including walnuts in the diets of adults at risk for type 2 diabetes mellitus (T2DM) led to improved overall diet quality. This report examines the specific changes in their nutrient intake.

Design:

This was a randomized, controlled, modified Latin square parallel design trial with 2 treatment arms. Participants were randomized to walnut intake with, or without, dietary advice to regulate caloric intake. Within each treatment arm, they were further randomized to one of 2 sequence permutations (walnut-included/walnut-excluded or walnut-excluded/walnut-included diet), with a 3-month washout between treatment phases.

Setting:

Community hospital in Lower Naugatuck Valley in Connecticut.

Participants:

Cohort of 112 participants (31 men and 81 women) at risk for T2DM.

Intervention:

Participants included 56 g (366 kcal) of walnuts in their daily diets for 6 months.

Measures:

Nutrient intake was assessed using web-based Automated Self-Administered 24-Hour Dietary Assessment.

Analysis:

Data were analyzed using generalized linear models.

Results:

Walnut inclusion led to increased intake of total fat, calcium, magnesium, thiamin, total saturated fatty acids, and monounsaturated and polyunsaturated fatty acids (379.0 ± 90.3 g vs −136.5 ± 92.7 g, P < .01; 230.7 ± 114.2 mg vs −95.2 ± 117.4 mg, P = .05; 111.0 ± 33.9 mg vs −32.3 ± 34.9 mg, P < .01; 0.28 ± 0.2 mg vs −0.47 ± 0.2 mg, P = .02; 8.6 ± 3.4 g vs −1.1 ± 3.5 g, P =.05; 6.3 ± 3.9 g vs −6.3 ± 4.0 g, P = .03; and 25.4 ± 4.0 vs −6.6 ± 4.2 g, P < .01, respectively). Vitamin C intake decreased (−65.3 ± 55.3 mg vs 98.9 ± 56.8 mg, P = .04). Protein intake increased from baseline with the inclusion of walnuts (20.0 ± 8.8 g, P < .05). Walnut inclusion led to an increase in total calories consumed when caloric intake is not regulated.

Conclusion:

Including walnuts in the diets of these adults led to increased dietary intake of some nutrients associated with lower risk of developing T2DM and other cardiometabolic risk factors.