Nutrition and night shift work

Rationale: Night shift workers have a 30 percent higher risk of making (medical) errors or having accidents than day shift workers. This is mainly the result of shift work-related fatigue which is related to lower alertness levels. Alertness levels are at lowest between 2:00h and 6:00h in the early morning, and eating a large meal may impair alertness levels even further. Not eating, or eating one or more small meals during the night shift could improve alertness levels. Objectives: 1) To investigate the effect of either the consumption of 1 or 3 small meals compared to no meal during the night shift on alertness levels, gastrointestinal complaints and glucose levels. 2) To investigate the effect of low glycaemic loaded meal(s) compared to high glycaemic loaded meal(s) during the night shift on alertness levels, gastrointestinal complaints and glucose levels. Study design: 2-armed randomized cross-over intervention study, where each study arm consist of three intervention periods. In one study arm participants will receive 3 small meals during the night shift and in the other study arm participants will receive 1 small meal during the night shift. Study population: 60 healthy female nurses who work the night shift at Hospital Gelderse Vallei (ZGV), aged 18 to 67 years old. Intervention: During two of the three intervention periods, nurses will receive either 1 small meal or 3 small meals during the night shift. During one of these two intervention periods the meals consist of carbohydrates high in glycaemic load and during the other intervention period the meals consist of carbohydrates low in glycaemic load. During a third intervention period participants in both study arms will receive no meal during the night shift as a control. Main study parameters/endpoints: The main study parameters will be objective alertness measured as total number of lapses and reciprocal reaction time. Secondary study parameters will be subjective alertness levels, gastrointestinal complaints and glucose levels.

1) To investigate the effect of either the consumption of 1 or 3 small meals compared to no meal during the night shift on alertness levels, gastrointestinal complaints and glucose levels. 2) To investigate the effect of low glycaemic loaded meal(s) compared to high glycaemic loaded meal(s) during the night shift on alertness levels, gastrointestinal complaints and glucose levels.

"A 2-armed randomized cross-over intervention study.
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"In one study arm participants will receive 3 small meals during the night shift and in the other study arm participants will receive 1 small meal during the night shift. Each study arm consist of three intervention periods.
During one of these intervention periods the meals consist of carbohydrates high in glycaemic load and during the other intervention period the meals consist of carbohydrates low in glycaemic load. During a third intervention period participants in both study arms will receive no meal during the night shift."

Participation in the study will not bring any risks. Also patient safety will not be jeopardized. The burden for participants will be kept as low as possible. The placement of the CGM, though quite non-obtrusive, can be considered as a burden for the participants. The calibration of the CGM may be considered a burden due to the finger prick that is required four times a day by a glucose meter. Participants will have to invest approximately 5 hours in the study, therefore time investment could be a potential burden. Also following the dietary regimen can be considered as a burden. As a personal benefit, participants get more insight in their eating patterns, alertness levels and glucose metabolism.