Tryptophan Supplementation to Improve Night Shift Workers' Health

Chrononutrition of Using L-tryptophan Supplementation to Alleviate the Impacts of Night Shift Rotation on Circadian Hormones and Health Outcomes

This randomized cross-over double-blinded trial aims to investigate the health effect of oral l-tryptophan supplementation on workers who rotate night shift work, and to examine the influences of different frequencies and timings of supplementation on the health effects.

Study Overview

• Status: Completed
• Conditions: Burnout; Sleep; Mood; Melatonin Deficiency; Cortisol Deficiency
• Intervention / Treatment: Dietary supplement: Tryptophan supplement; Dietary supplement: Maltose

Detailed Description

This study aims to investigate the health effect of oral l-tryptophan supplementation on workers who rotate night shift work, and to examine the influences of different frequencies and timings of supplementation on the health effects. Night shift work affects melatonin and cortisol variation, insomnia, mood issues, and metabolic syndrome. Short-term tryptophan supplementation was shown to improve melatonin, sleep quality, and cortisol response to acute stress. Little is known whether a longer term of longer-term tryptophan supplementation would alleviate the health impacts of night shift work. Nevertheless, melatonin and cortisol have their normal circadian patterns. Nothing is known about what temporal structure of tryptophan supplement would maximize its health effects on night shift workers melatonin and cortisol levels. We will conduct a double-blind cross-over randomized controlled trial to examine the benefits of oral tryptophan administration (3g/day, t.i.d.) on night shift workers' health outcomes: melatonin and cortisol levels, sleep quality, moods and work performance. We expect to reveal the health effect of tryptophan supplementation in night shift workers by using sophisticated study design.

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Taiwan
  • Taipei, Taiwan, 112
    • National Yang-Ming University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion criteria:

• Age: adults >=20 y/o
• Adults who had night shift schedule >1 month before enrollment, and will have similar night shift schedule in the following 2 months. (Eligible night shift schedule: >1 day of evening or night shift in a week)
• People who will not have plans to travel to another time zone in the following 2-3 months
• People who will plan to stay in the same job position for the following 3 months
• People who have no experience in taking tryptophan or melatonin supplement in the past month
• Body weight >= 50kg and <=80kg
• Non-pregnant, non-breastfeeding, not taking contraceptives
• Not under treatment of steroids, not taking sleeping pills

Exclusion criteria:

• diagnosis of renal or liver diseases
• diagnosis of Cushing's Disease, Addison's disease
• psychiatric diagnosis, such as depression and anxiety disorders
• neurological diseases such as dementia, epilepsy, Parkinson's disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Tryptophan supplement; Pure L-tryptophan in capsules (500mg/capsule); 3g tryptophan per day (2 capsules, t.i.d.), at 8AM, 4PM, and 0AM (± 1 hour)	Dietary supplement: Tryptophan supplement; Pure L-tryptophan in capsules (500mg/capsule); 3g tryptophan per day (2 capsules, t.i.d.), at 8AM, 4PM, and 0AM (± 1 hour)
Placebo Comparator: Maltose; Placebo is maltose powder capsule (500mg/capsule); 3g maltose powder per day (2 capsules, t.i.d.), at 8AM, 4PM, and 0AM (± 1 hour)	Dietary supplement: Maltose; Maltose

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Melatonin level in the morning	Morning (8AM) saliva melatonin level change in the phase	3 weeks
Melatonin level in the afternoon	Afternoon (4PM) saliva melatonin level change in the phase	3 weeks
Melatonin level at midnight	Midnight (0AM) saliva melatonin level change in the phase	3 weeks
Cortisol level in the morning	Morning (8AM) saliva cortisol level change in the phase	3 weeks
Cortisol level in the afternoon	Afternoon (4PM) saliva cortisol level change in the phase	3 weeks
Cortisol level at midnight	Midnight (0AM) saliva cortisol level change in the phase	3 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sleep quality	Pittsburg Sleep Quality Score (range: 0-21) at the end of the phase. The higher score indicates worse sleep quality	3 weeks
Mood states, depression	Depression, Anxiety, Stress Scales. Depression score (range 0-42) changes in the phase. The higher score, the more depressed.	3 weeks
Mood states, anxiety	Depression, Anxiety, Stress Scales. Anxiety score (range 0-42) changes in the phase. The higher score, the more anxious.	3 weeks
Mood states, stress	Depression, Anxiety, Stress Scales. Stress score (range 0-42) changes in the phase. The higher score, the more stressful.	3 weeks

Collaborators and Investigators

• Sponsor: National Yang Ming University

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2019
• Primary Completion (Actual): September 1, 2020
• Study Completion (Actual): December 31, 2020

Study Registration Dates

• First Submitted: June 23, 2020
• First Submitted That Met QC Criteria: August 6, 2020
• First Posted (Actual): August 10, 2020

Study Record Updates

• Last Update Posted (Actual): March 22, 2021
• Last Update Submitted That Met QC Criteria: March 19, 2021
• Last Verified: March 1, 2021

More Information

Terms related to this study

• Keywords: melatonin; randomized trial; cortisol; shift work; tryptophan
• Additional Relevant MeSH Terms: Behavioral Symptoms; Stress, Psychological; Burnout, Psychological; Psychotropic Drugs; Antidepressive Agents; Antidepressive Agents, Second-Generation; Tryptophan
• Other Study ID Numbers: YM106114F

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No
• IPD Plan Description: The participants did not provide agreement to the researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No