The effect of walnut butter product and nutrition education on weight and endothelial health in overweight adolescents

This study investigated the effects of walnut butter (WB) consumption and nutrition education (NE) on body composition, specifically on fat to muscle mass ratio, and endothelial health, including endothelial health biomarkers vascular cellular adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and P-selectin in adolescents with overweight and obesity. Eighty adolescents, aged thirteen to seventeen, were recruited for this randomized-controlled, parallel, four visit study. Participants were randomized to consume 45 grams of WB for four months and receive nutrition education at baseline and midpoint visits or receive nutrition education only at baseline and midpoint visits. Dual energy x-ray absorptiometry (DXA) was used to measure body composition. EndoPAT was used to measure endothelial function, and a fasting blood draw was collected to assess endothelial health biomarkers. Differences within and between treatments were analyzed using the Mann-Whitney U and Wilcoxon signed ranked test. A subset of data was evaluated, as this study is still ongoing, which may have impacted results. There was no significant difference in fat to muscle mass ration between the two groups at the final visit (p = 0.342). There was no significant difference in visceral adipose tissue (VAT) mass (g), or VAT volume (cm³) between the control (NE) and treatment (NE+WB) group at final visit (p= 0.812). There was a noted difference in reactive hyperemia index (RHI) at baseline (p=.611) and final (p=.057) between the two groups, however, these changes were not statistically significant. Although inflammatory markers were reduced from baseline to final visit in each group, these differences were not significant. The outcomes of this study did not show significant effects of a walnut butter treatment on increased muscle mass and reduced fat mass, endothelial function, or inflammatory markers.