The effect of meal frequency and glycemic index during the night shift on alertness, hunger and gastrointestinal complaints in female health care workers - a two-armed randomized cross-over trial.

Abstract

Background: Nutrition strategies for night shift workers could optimize alertness, and minimize hunger and reduce gastrointestinal complaints, enhancing safety and well-being.

Objective: To investigate the effects of 1 or 3 small meals, with either low or high glycemic index (GI), compared to no meal, on alertness, hunger, and gastrointestinal complaints during the night shift.

Methods: Fifty-one female healthcare workers, aged 18 to 61, participated in a 2-armed randomized cross-over design. In one study arm, participants received one yogurt meal during the night shift, in the other, they received three. Each study-arm involved three intervention periods during night shifts, with participants consuming yoghurt with low GI (1LGI or 3LGI), high GI (1HGI or 3HGI) carbohydrates or no meal (0NGI). Objective alertness was assessed using a validated brief psychomotor vigilance task (PVT-B), subjective alertness with the Samn-Perelli scale, and hunger and gastrointestinal complaints through questionnaires.

Results: Participants in the 1LGI (ß -4.6; 95% CI 0.0, 9.3) and 3LGI (ß -3.4; 95% CI 0.0, 6.8) conditions had fewer lapses during the PVT-B than those in the 3HGI condition. No differences were found between meal conditions for median and reciprocal reaction time or subjective alertness. All four conditions reported less hunger (ß from -0.6 to -1.2) compared to no meal. The 3LGI condition resulted in more rumbling intestines than the 3HGI (ß 1.1; 95% CI 0.4, 1.7) and 0NGI (ß 0.74; 95% CI 0.11, 1.37) conditions.

Conclusions: Our study suggests that consuming three small low GI meals during the night shift helps maintain alertness, and reduces lapses compared to three high GI meals. It also minimizes hunger but may cause mild gastrointestinal complaints. https://trialsearch.who.int/Trial2.aspx?TrialID=NL-OMON25574.