Article Text

Download PDFPDF

Inclusion of walnut in the diets of adults at risk for type 2 diabetes and their dietary pattern changes: a randomized, controlled, cross-over trial
  1. Valentine Yanchou Njike1,2,
  2. Niloufarsadat Yarandi2,
  3. Paul Petraro2,
  4. Rockiy G Ayettey1,2,
  5. Judith A Treu1,2,
  6. David L Katz1,2
  1. 1Yale University Prevention Research Center, Derby, Connecticut, USA
  2. 2Griffin Hospital—Derby, Derby, Connecticut, USA
  1. Correspondence to Dr David L Katz; davkatz7{at}


Background In our recently published study, including walnuts in the diets of adults with prediabetes led to overall improvement in diet quality. This report adds to those study findings by examining the food groups displaced during walnut inclusion in the diets of those adults with prediabetes.

Methods Randomized, controlled, modified Latin square parallel design with 2 treatment arms. The 112 participants (31 men, 81 women) were randomly assigned to a diet with or without dietary counseling to regulate calorie intake in a 1:1 ratio. Within each treatment arm, participants were further randomized to 1 of 2 sequence permutations to receive a walnut-included diet with 56 g (366 kcal) of walnuts per day and a walnut-excluded diet. Participants in the calorie-regulated arm received advice from a dietitian to preserve an isocaloric condition while including walnuts. We analyzed the 12 components of the 2010 Healthy Eating Index to examine dietary pattern changes of study participants.

Results Seafood and plant protein foods intake significantly increased with walnut inclusion, compared with their exclusion (2.14±2.06 vs −0.49±2.33; p=0.003). The ingestion of healthful fatty acids also significantly increased with walnut inclusion, compared with their exclusion (1.43±4.53 vs −1.76±4.80; p=0.02). Dairy ingestion increased with walnut inclusion in the calorie-regulated phase, compared with walnut inclusion without calorie regulation (1.06±4.42 vs −2.15±3.64; p=0.02).

Conclusions Our data suggest that walnut inclusion in the diets of adults at risk for diabetes led to an increase in intake of other healthful foods.

Trial registration number NCT02330848.

  • A1C
  • Nutrition
  • Nuts

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Contributors VYN was involved in study design, project oversight, data analysis, data interpretation, developed manuscript draft, final approval. NY assisted with development of manuscript draft. RGA was the project coordinator. PP conducted statistical analysis, data interpretation. JAT was the study dietitian and provided critical review. DLK was involved in study design, project oversight, data interpretation, critical review of paper, final approval. All authors have reviewed and approve of the completed revised manuscript.

  • Funding Funding for this study has been provided by the California Walnut Commission.

  • Competing interests This study was conducted with funding from the Centers for Disease Control and Prevention and the California Walnut Commission. DLK has been compensated for public speaking by the California Walnut Commission.

  • Ethics approval Griffin Hospital Institutional Review Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data are available.