Efeitos da suplementação de melatonina nos marcadores de risco de diabetes de acordo com o perfil lipídico da dieta em trabalhadoras noturnas

Abstract

Background: Interactions between circadian clocks and key mediators of chronic low-grade inflammation associated with fat consumption may be important in maintaining metabolic homeostasis, as well as a risk for the development of obesity-associated comorbidities, especially type 2 diabetes (DM2). Aims: To evaluate the effects of melatonin supplementation on diabetes risk markers, according to the lipidic profile of the diet (pro-inflammatory versus anti-inflammatory) in overweight female night workers. Additionally, to evaluate the effect of melatonin supplementation on the profile of fat consumption. Methods: This is a randomized, controlled, double-blind, crossover clinical trial with 27 nursing professionals who worked permanent night shifts. The melatonin group administered synthetic melatonin (3 mg) only on days off and between shifts, that is, on days when they slept at night, for 12 weeks. The placebo group was instructed to use a pill identical to melatonin, for 12 weeks, but this was a placebo. Participants performed food diaries on a typical workday and a typical day off at the baseline, and every month until the end of the protocol (6 months). The Nutrition Data System for Research software (2007 version) was used to assess the dietary profile. The dietary fat profile considered saturated, monounsaturated, polyunsaturated, trans, cholesterol, eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) and total fat. For the characterization of fatty acids according to inflammatory characteristics, the average consumption in grams of lipids from the workday and day off at the baseline and the end of the first and second phases were grouped (pro-inflammatory: saturated fats, trans fats and cholesterol; anti-inflammatory: monounsaturated, polyunsaturated fats, EPA+DHA). At baseline and the end of each phase, blood glucose, insulin, glycated hemoglobin (HbA1c) and HOMA-IR plasma concentrations were collected. In order to evaluate the effect of melatonin supplementation on the profile of fat consumption and on the markers of diabetes risk according to the lipidic profile of the diet, a generalized linear model was carried out, having as adjustment variables age, lifetime exposure to night work and body mass index (BMI). For statistical analyses, Statistica 12.0 and STATA 14.0 softwares were used. Results: The mean age of the participants was 37.1 years (SD 5.9 years) and BMI was 29.9 kg/m² (SD 3.3 kg/m²). The mean time of work in the hospital was 7.9 years (SD 3.8 years) and the median for night work at the institution was 5.3 years (AIQ 2-4 years). At the baseline, mean blood glucose, insulin and HbA1c were within the reference ranges and the median HOMA-IR was 3.1 (AIQ 2.0-4.8), a value higher than recommended. Regarding total dietary fat, 81.5% of the participants had consumption within the recommendations (20-35%), with a median consumption of 60.62 g/day of fat (AIQ 28.6-72.7 g/day). Melatonin supplementation did not change the fat consumption profile (saturated, trans, polyunsaturated, monounsaturated, EPA+DHA and cholesterol), and did not influence diabetes risk markers, according to the consumption of pro-inflammatory and anti-inflammatory fats or total fat. Conclusion: In summary, 12 weeks of melatonin supplementation had no effect on DM2 risk markers according to dietary lipidic profile (pro-inflammatory or anti-inflammatory potential) in overweight female night workers. Melatonin did not change the profile of fat consumption throughout the intervention, whether for total fats, isolated or dichotomized into anti-inflammatory or pro-inflammatory fats.