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

Abstract

BackgroundIn 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.MethodsRandomized, 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.ResultsSeafood 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).ConclusionsOur 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 numberNCT02330848.

Effects of Pistachio Consumption in a Behavioral Weight Loss Intervention on Weight Change, Cardiometabolic Factors, and Dietary Intake

“…Change in dietary intake and food choices in free-living individuals in response to prescribing other nuts (walnuts, almonds, and hazelnuts) has been examined in a few previous studies [ 19 , 40 , 41 , 42 , 43 , 44 ]. In most of these studies, displacement of other foods generally improved nutritional quality of the diet and may also explain why the addition of nuts to the diet does not promote weight gain.…”

The effect of walnut consumption on cardiometabolic profiles of individuals with abnormal glucose homoeostasis: a systematic review and meta-analysis of clinical trials

“…These studies were published between 2004 and 2017. Nine publications were reported from American countries (11,12,(14)(15)(16)(17)(18)(19)(20) , two from South Africa (21,22) and the other one from China (23) . Age of participants was between 20 and 75 years.…”

Effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes: a systematic review of randomised controlled trials

“…Out of the remaining fourteen articles, five articles reported on subjects at high risk of developing T2D (25)(26)(27)(28)(29) and nine articles reported on subjects with prediabetes (30)(31)(32)(33)(34)(35)(36)(37)(38) . Six articles were excluded for the following reasons; one article (27) did not include criteria for defining prediabetes; one article (29) assessed only diet quality and food group consumption; in one article (26) which defined prediabetes as 2-h PG during OGTT of 140-199 mg/dl (7•8-11•0 mmol/l), the mean baseline value of 2-h PG was lower than the bottom cut-off point for defining IGT-prediabetes; one article (25) aimed to investigate the first-meal (0-240 min) and second-meal (240-490 min) effects of nut consumption; one article (37) was excluded because it did not report intervention studies with nuts or seeds, but rather tested ad libitum diets with different glycaemic load or a high-fat/low-carbohydrate hypoenergetic diet; finally, one article (30) was excluded because it did not meet the eligibility criteria with respect to the control; ground flaxseed was tested against equal amount of ground wheat bran. In other words, that study was aimed to determine the effects of flaxseed over the effects of wheat bran, instead of a flaxseed-free diet in general.…”