The Role of Walnut Consumption on Sleep Quality

Not Applicable

Completed

• Conditions: Sleep; Healthy Diet
• Interventions: Other: Walnut intake; Other: Control

• Registration Number: NCT04799821
• Lead Sponsor: University of Barcelona

Brief Summary

Walnuts have a unique nutritional profile, including the sleep-regulating hormone melatonin, tryptophan, and omega-3 fatty acids, the two latest nutrients involved in melatonin and serotonin synthesis. Although it has been claimed that walnuts may improve sleep, to the investigators' knowledge, no studies have been conducted to objectively determine the impact of walnut consumption on sleep and overall well-being. Therefore, this study aims to investigate the effect of daily walnut consumption on sleep parameters (such as quality and duration). Secondarily, it aims to investigate the impact of daily walnut consumption on body composition, eating behavior, and well-being.

Detailed Description

The study to investigate the effect of daily walnut consumption on sleep quality will be conducted in an 18-week randomized crossover trial, in which participants will be initially assigned to intervention or control conditions for 8-weeks. After 2 weeks of washout, subjects will be crossed over to the alternate intervention and will continue for another 8 weeks. Note that throughout the whole study, each participant will attend 5 visits: 1 initial visit (baseline) and 2 visits in each one of the study conditions (intervention and control).

Study Timeline

• Study Start: 2021-02-01
• Study First Submitted: 2021-02-12
• Study First Submitted QC: 2021-03-11
• Study First Posted: 2021-03-16
• Primary Completion: 2022-07-31
• Study Completion: 2023-03-31
• Status Verified: 2023-11
• Last Update Submitted: 2023-11-28
• Last Update Posted: 2023-11-29

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

• BMI 19-26 kg/m^2
• Habitual moderate exercise level
• No recent history of weight change exceeding 2.3kg (5lb) within the prior 3 months.

Exclusion Criteria

• Nuts allergy
• Any acute or chronic diseases
• Smokers
• Any drugs or supplementations
• Any alimentary restrictions or specific diets
• Being a shift or night workers
• Being unable to give written informed consent.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Intervention	Walnut intake	Daily walnut consumption
Control	Control	No walnut consumption

Primary Outcome Measures

Name	Time	Method
Changes in sleep onset latency from baseline to weeks 4, 8, 14, and 18	Weeks 4, 8, 14 and 18	Measured in hours of sleep with an actigraph (ActTrust, CONDOR, Brazil)
Changes in sleep efficiency from baseline to weeks 4, 8, 14, and 18	Weeks 4, 8, 14 and 18	Calculated in percentage as the ratio of total sleep time (TST) to time in bed (TIB).; Sleep efficiency (percent) = (TST/TIB)\*100
Changes in wake after sleep onset (WASO) from baseline to weeks 4, 8, 14, and 18	Week 4, 8, 14, and 18	Measured in minutes of WASO with an actigraph (ActTrust, CONDOR, Brazil)
Changes in sleep duration from baseline to weeks 4, 8, 14, and 18	Weeks 4, 8, 14, and 18	Measured in hours of sleep time with an actigraph (ActTrust, CONDOR, Brazil)
Changes in urinary 6-sulphaoxymelatonin from baseline to week 4, 8, 14 and 18	Week 4, 8, 14 and 18	Quantified using urine Melatonin-Sulfate ELISA kit

Secondary Outcome Measures

Name	Time	Method
Changes in body fat from baseline to weeks 4, 8, 14, and 18	Weeks 4, 8, 14 and 18	Measured as the percentage of body fat with a body composition analyzer (Inbody 120, Korea)
Changes in well-being from baseline to weeks 8 and 18	Weeks 8 and 18	Well-being will be measured with the Spanish version of the WHO-5 Well-being Index (Lucas-Carrasco et. al. 2012).; Scores range from 0 to 100, with higher scores indicating higher well-being.
Changes in body mass index (BMI) from baseline to weeks 4, 8, 14, and 18	Weeks 4, 8, 14 and 18	Calculated as weight (kg) divided by height (in squared meters), BMI= kg/m\^2
Changes in weight circumference from baseline to weeks 4, 8, 14, and 18	Weeks 4, 8, 14 and 18	Measured midway between the lower rib margin and the iliac crest with the subject standing and wearing only underwear, at the end of gentle expiration with an anthropometric tape (CESCORF, Brazil)
Changes in eating behavior from baseline to weeks 8 and 18	Weeks 8 and 18	To evaluate changes in eating behavior, the Spanish version of the Food Cravings Questionnaire will be used (Cepeda-Benito et al, 2000).; This questionnaire evaluates 10 dimensions of eating behavior: * Having Intentions and Plans to Consume Food; * Anticipation of Positive Reinforcement that may Result from Eating; * Anticipation of Relief from Negative States and Feelings as a Result of Eating; * Lack of Control over Eating; * Thoughts or Preoccupation with Food; * Having Intentions and Plans to Consume Food; * Craving as a Physiological State; * Emotions that may be Experienced Before or During Food Cravings or Eating; * Cues that may Trigger Food Cravings; * Guilt from Cravings and/or for Giving in to Them; For each subscale, scores range from 0 to 5, with higher scores indicating a stronger sensation of craving.

Trial Locations

Locations (1)

Torribera Campus, University of Barcelona; 🇪🇸 Santa Coloma de Gramenet, Barcelona, Spain