Working night shifts increases the risk of prediabetes and type 2 diabetes. But, exactly how shift-work causes diabetes has remained a matter of speculation for a long time. A new study suggests that eating both during day time and night time (as a lot of night shift workers do) interferes with circadian glucose rhythms and impairs glucose tolerance.
Most biological activities ebb and flow. Heart rate, blood pressure, body temperature, and the levels of hormones, all fluctuate cyclically every 24 hours. These cycles are called circadian rhythms. Such rhythms also influence sleep and eating.
Inside animals, circadian cycles are maintained by the ‘central circadian pacemaker’. In mammals this is a group of neurons called the suprachiasmatic nucleus. This is the body’s primary clock that all other biological clocks are constantly trying to synchronize with.
When the central pacemaker and eating/fasting cycles are perfectly synchronized, all goes well. But, when people eat both during night time and day time, the biological clock that keeps tracks of eating/fasting sends timestamps to organs that conflicts with the timestamps of the central pacemaker.
It is this misalignment between the central pacemaker and the eating/fasting cycle that the study implicates as the reason for glucose tolerance impairment. But, there might be a way to counteract the effects of misalignment – restricting meals to day time.
To test the effectiveness of this intervention, researchers simulated night shift work in 2 groups of people. Both groups of participants in the study followed a 28 hour clock to desynchronize their daily activities with their central pacemaker (sleep/wake, rest/activity, supine/upright posture, exposure to dark/light, etc.) .
While one group ate their meals according to 28 hour clock (and hence effectively ate during both day and night), the other restricted meals to day time. Simulated night work significantly affected circadian glucose rhythms in the former but not in the latter.
“Meals allocated to the habitual daytime rather than to the nighttime, can maintain internal circadian alignment and prevent the adverse effects of simulated night shift work on glucose tolerance and pancreatic cell function”
According to researchers, night shift workers can “restrict meals to the daytime to mitigate impaired glucose tolerance” and likely reduce risk of diabetes. Read more about the study here.
Article: Daytime eating prevents internal circadian misalignment and glucose intolerance in night work
Authors: Sarah L. Chellappa, Jingyi Qian, Nina Vujovic, Christopher J. Morris, Arlet Nedeltcheva, Hoa Nguyen, Nishath Rahman, Su Wei Heng, Lauren Kelly, Kayla Kerlin-Monteiro, Suhina Srivastav, Wei Wang, Daniel Aeschbach, Charles A. Czeisler, Steven A. Shea, Gail K. Adler, Marta Garaulet, and Frank A. J. L. Scheer.
