Opting for low GI meals viable alternative to fasting during night shifts, promoting better glucose homeostasis: Study

The study showed that the results for one low-GI meal during the night shift did not differ from a glucose profile after no meal.

"Consumption of one or three low-glycemic index meals did not lead to significant changes in glucose homeostasis compared to fasting overnight," the researchers reported. On the contrary, the consumption of 1 high-glycemic index meal significantly raised all glycemic control variables during the night shifts and in the morning.

Previous studies revealed a significantly higher risk of all-cause, cardiovascular, and cancer mortality in night workers compared with daytime workers. These associations may also be partly medicated by poorer healthy lifestyles among night workers, including less fruit and vegetable consumption, lower physical activity, and more smoking. The contribution of circadian disruption in disease development may also play a role.

Night shift workers are exposed to circadian disruption that contributes to impaired glucose tolerance. Circadian disruption can be defined as the misalignment between the central and peripheral circadian clock that occurs as the manifestation of, for example, working night shifts.

Although fasting during the night shift improves glucose homeostasis, adhering to this dietary strategy may be challenging. Edith JM Feskens, Wageningen University and Research, Wageningen, the Netherlands, and colleagues evaluated the effect of fasting compared with meal consumption with different combinations of glycemic index (GI, low or high) and frequency (1 or 3 times) during the night shift on continuous glucose monitoring metrics.

For this purpose, the researchers conducted a 2-arm randomized cross-over trial on female nurses working night shifts. In each of the arms, the participants were either provided no meal (fasting), low GI, or high-GI meal during the night shift with a meal frequency according to which arm they were randomly allocated to, either 1-MEAL or 3-MEAL.

Outcome variables included glycemic control and variability (GC and GV) metrics during the night shift (21:30–7:00), in the morning after the night shift (07:00–13:00), and the 24 hours (18:00–18:00).

Based on the study, the researchers reported the following findings:

• Compared to no meal, the consumption of 1 high-GI meal increased all GV metrics not only during the night shifts but also in the morning, for instance, as observed in the coefficient of variation (β = 0.03 mmol/L), and GV percentage (β = 4.13).
• The consumption of 1 or 3 low-GI meals did not raise GC or GV metrics except for continuous overall net glycemic action during the night shifts after consuming three low-GI meals.
• When controlling for GI, night shift meal frequency did not affect any metrics in any timeframe.

The results showed that compared to no meal condition, intake of high GI meals during night shifts raised both GV and GV, whereas consuming low GI meals showed a similar effect on GC and GV as that of no meal irrespective of meal frequency.

"These findings indicate that opting for low glycemic index meals, irrespective of their frequency, appears to be a viable alternative to fasting during night shifts, promoting better glucose homeostasis," the researchers concluded.

Reference:

Suyoto, P. S., De Rijk, M. G., De Vries, J. H., & Feskens, E. J. (2023). The Effect of Meal Glycemic Index and Meal Frequency on Glycemic Control and Variability in Female Nurses Working Night Shifts: A Two-Arm Randomized Cross-Over Trial. The Journal of Nutrition, 154(1), 69-78. https://doi.org/10.1016/j.tjnut.2023.11.025