New research finds that night shift knocks the digestive system out of sync with the body’s central biological clock.

The study revealed that just three days of being on a night shift schedule will disrupt the body’s metabolism. This disruption appears to be driven by separate biological clocks in the liver, gut and pancreas, rather than the brain’s master clock.

The new research, from the Sleep and Performance Research centre at Washington State University and published in the online edition of the Proceedings of the National Academy of Sciences, dispels the belief that the metabolic disruption in shift workers is driven primarily by the brain’s master clock, reports Science Daily.

Instead, the study revealed that separate biological clocks – called peripheral oscillators – in the liver, gut and pancreas, have a mind of their own.

“Some biological signals in shift workers’ bodies are saying it’s day while other signals are saying it’s night, which causes disruption of metabolism,” said the head researcher Hans Van Dongen.

The results showed that three night shifts in a row moved the brain’s master clock by about two hours on average. But the impact on the digestive system’s clock was massive, with the brace of night shifts knocking it out by 12 hours.

The night shifts also disrupted the rhythms of two metabolites that are linked to chronic liver disease.