Voeding en nachtdienstwerk

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.

It is expected that three small meals will not further deteriorate alertness levels and will reduce hunger feelings compared to one small meal during the night shift. Moreover, it is expected that meals low in glycaemic load will lead to smaller deterioration of the blood glucose levels than meals high in glycaemic load and will also result in better alertness levels during the night shift.

Three intervention periods with at least 2 weeks in between. Each intervention period will last approximately 4 to 5 days and will contain 2-3 consecutive night shifts.

In de ene studiearm krijgen de deelnemers 3 kleine maaltijden tijdens de nachtdienst en in de andere studiearm krijgen de deelnemers 1 kleine maaltijd tijdens de nachtdienst. Elke onderzoeksarm bestaat uit drie interventieperiodes.

Tijdens één van deze interventieperiodes bestaan de maaltijden uit koolhydraten met een hoge glycemische lading en tijdens de andere interventieperiode bestaan de maaltijden uit koolhydraten met een lage glycemische lading. Tijdens een derde interventieperiode krijgen deelnemers in beide studiearmen geen maaltijd tijdens de nachtdienst.