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.
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
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
30
* Pure L-tryptophan in capsules (500mg/capsule) * 3g tryptophan per day (2 capsules, t.i.d.), at 8AM, 4PM, and 0AM (± 1 hour)
Maltose
National Yang-Ming University
Taipei, Taiwan
Melatonin level in the morning
Morning (8AM) saliva melatonin level change in the phase
Time frame: 3 weeks
Melatonin level in the afternoon
Afternoon (4PM) saliva melatonin level change in the phase
Time frame: 3 weeks
Melatonin level at midnight
Midnight (0AM) saliva melatonin level change in the phase
Time frame: 3 weeks
Cortisol level in the morning
Morning (8AM) saliva cortisol level change in the phase
Time frame: 3 weeks
Cortisol level in the afternoon
Afternoon (4PM) saliva cortisol level change in the phase
Time frame: 3 weeks
Cortisol level at midnight
Midnight (0AM) saliva cortisol level change in the phase
Time frame: 3 weeks
Sleep quality
Pittsburg Sleep Quality Score (range: 0-21) at the end of the phase. The higher score indicates worse sleep quality
Time frame: 3 weeks
Mood states, depression
Depression, Anxiety, Stress Scales. Depression score (range 0-42) changes in the phase. The higher score, the more depressed.
Time frame: 3 weeks
Mood states, anxiety
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Depression, Anxiety, Stress Scales. Anxiety score (range 0-42) changes in the phase. The higher score, the more anxious.
Time frame: 3 weeks
Mood states, stress
Depression, Anxiety, Stress Scales. Stress score (range 0-42) changes in the phase. The higher score, the more stressful.
Time frame: 3 weeks