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| Author(s): |
Cristina Souza da Silva Luz
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR) |
| Defense date: | 2025-05-05 |
| Examining board members: |
Claudia Roberta de Castro Moreno;
Tassia do Vale Cardoso Lopes;
Gabriel Natan de Souza Pires
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| Advisor: | Claudia Roberta de Castro Moreno |
| Abstract | |
Introduction: Poor sleep quality is associated with unhealthy dietary choices and worse body composition among night-shift workers and women during the climacteric period. Melatonin therapy may improve sleep, potentially influencing dietary intake and, consequently, body composition. Objective: To evaluate the effect of exogenous melatonin administration on dietary intake and body composition in healthcare workers exposed to fixed-shift work during the climacteric period. Methods: This Phase II randomized, double-blind, placebo-controlled clinical trial included climacteric women working fixed morning, afternoon, or night shifts. At baseline, data collection included sociodemographic information, self-reported sleep parameters, dietary intake via food diaries, and body composition analysis using bioelectrical impedance. Two urine samples were collected: one before the intervention (Urine Zero) to estimate 6-sulfatoxymelatonin levels and another after the first intervention day (Urine 1) to verify whether the administered melatonin dose was excessive. After baseline, participants received either 0.3 mg of melatonin or placebo for three months. The baseline procedures were repeated post-intervention for comparison. Results: At baseline, total caloric and carbohydrate intake were higher among night-shift workers compared to afternoon-shift workers, with statistically significant differences for both calories (p = 0.02) and carbohydrates (p = 0.01). Fat-free mass and body fat percentage were significantly higher among afternoon-shift workers compared to night-shift workers (p= 0.02). Fat-free mass was significantly lower in afternoon-shift workers compared to night-shift workers (p= 0.015), whereas body fat percentage was higher in afternoon-shift workers than in night-shift workers (p= 0.02). After the intervention, no significant differences were observed in mean total caloric intake (p= 0.16) or body composition (p= 0.07) between the intervention and placebo groups. However, postmenopausal participants showed a reduction in body fat compared to premenopausal participants, who experienced a increase, regardless of the intervention (p= 0.04). Conclusion: It can be stated that doses restoring physiological nighttime melatonin levels, when administered on non-consecutive nights over three months, were not sufficient to modify food intake or body composition. (AU) | |
| FAPESP's process: | 23/01780-1 - DIET QUALITY AND MEALTIME OF NIGHT WORKERS IN CLIMATERIAL: AN INTERVENTION STUDY WITH EXOGENOUS MELATONIN |
| Grantee: | Cristina Souza da Silva Luz |
| Support Opportunities: | Scholarships in Brazil - Master |