Efeito da ingestão de uma refeição hiperproteica durante o turno noturno sobre a resposta metabólica pós-prandial no dia seguinte: um estudo crossover, randomizado e controlado

Abstract

Introduction: Shift work has been associated with nutritional and metabolic diseases, and the quality, quantity and time of eating are considered important factors associated with the development of chronic diseases and weight gain in shift workers. However, the impact of nocturnal eating on the metabolic response of shift workers is poorly explored in the literature. Objective: To evaluate the acute effect of a high-protein meal compared to a normal protein meal served at night on the postprandial metabolic response of night workers the following day. Material and methods: A crossover clinical trial was performed with 14 male night workers. Participants were followed for 7 days before each intervention night in relation to food consumption and sleep pattern. After, the participants were underwent two different isocaloric dietary conditions at 1:00 h of the night shift, with a 6-day washout period between them: high-protein (HP) meal containing 45% carbohydrate, 35% protein and 20% fat; and normal protein (NP) meal containing 65% carbohydrate, 15% protein and 20% fat. Postprandial capillary glucose levels were determined immediately before intake of the test meal (time 0) and 30, 60, 90 and 120 minutes after the end of the meal. At the end of the work shift (6:30 h) participants received a standard breakfast and postprandial levels of glucose, insulin and triglycerides were determined immediately before (time 0) and then every 30 min for 2 h (30, 60, 90 and 120 minutes). The homeostatic model assessment for insulin resistance (HOMA-IR) was calculated in each of these conditions. The generalized estimating equation (GEE) and area under the curve (AUC) were used to determine differences between both interventions. Results: Higher values of capillary glucose were found after the NP condition compared to the HP condition (AUC = 119.46 ± 1.49 mg/dL x min and 102.95 ± 1.28 mg/dL x min, respectively; p < 0.001). For the metabolic response to standard breakfast the following day, no significant differences in glucose, insulin, triglyceride and HOMA-IR levels were found between interventions. Conclusion: A night meal with a higher percentage of protein leads to lower postprandial glucose levels during the night shift but exerts no effect on metabolic response at the beginning of the following day. Further studies should be performed to test the long-term effect of these conditions.