Night Shift Could Make It Difficult to Manage or Prevent Diabetes, Unless You Eat During the Daytime

Night shift can be hard on the body for a lot of reasons, but a recent study shows that it’s even worse for people with diabetes, specifically, type two diabetes. This is because our circadian rhythms are thrown off by eating during the night. Eating during the day could make a significant difference in a person’s ability to control their diabetes or prevent the onset of the disease.

In a randomized controlled trial, researchers from Brigham and Women’s Hospital asked 19 healthy young participants to stay awake for 32 hours in a highly controlled environment known as a “constant routine protocol.” They stayed in a dimly lit room, consumed the same snacks every hour, stayed in the same bodily position the majority of the time, and had no access to clocks.

Following that part of the study, participants went through a night-shift simulation in which they followed one of two eating schedules. Half the participants ate during the nighttime like a typical night-shift worker would. The other half ate during the day in order to align their eating patterns with the body’s 24-hour circadian rhythm.

All the participants then went through a second 40-hour-long constant routine protocol the way they had at first to test the effects their meal schedules had had on their circadian rhythms.

The researchers found that those participants who ate at night showed increased blood glucose levels during the final constant routine protocol, as well as decreased pancreatic beta-cell function. In those participants who ate during the day, there were no observable changes in their blood glucose levels and beta-cell function.

Nighttime eating, the researchers said, appears to cause a misalignment between the body’s central and peripheral circadian clocks, which can cause a problem with temperature control, glucose tolerance, and beta-cell function, leading to diabetes or to a decreased ability to manage one’s diabetes.

“These results indicate that meal timing was primarily responsible for the reported effects on glucose tolerance and beta-cell function, possibly due to the misalignment of central and peripheral ‘clocks’ throughout the body,” says Frank A.J.L. Scheer, PhD, MSc, co-corresponding author of the study. “While the central circadian ‘clock’ was still on Boston time, the endogenous circadian glucose rhythms suggest that some peripheral ‘clocks,’ as perhaps those in the liver, had dramatically shifted to a time zone in Asia.”

Researchers believe this data could also hold implications for other people with complicated schedules, such as those with circadian rhythm sleep disorders or who tend to sleep late on the weekends. It could also have an impact on people experiencing jet lag.

“Of the participants studied, those with the biggest disruption of their circadian system—here quantified as the misalignment between their central circadian ‘clock’ and their endogenous circadian glucose rhythms—showed the largest impairment of glucose tolerance,” says Scheer.

This research may help explain why type 2 diabetes is so prevalent among people who work the night shift. Night-shift workers typically sleep during the day and eat at nighttime when they’re awake for their jobs.

So if you’re a night-shift worker, consider moving your mealtimes to daytime, no matter how weird it might feel at first, in order to help keep your circadian rhythm aligned, your glucose tolerance in check, and your beta cells functioning well.

The study was published in the journal Science Advances.