Frequent international travels or working at night may harm your liver by disrupting the natural sleep-wake cycle of the body, a new study suggests.
Researchers, including those from University of Geneva (UNIGE) in Switzerland, showed that the size of the liver increases by almost half before returning to its initial dimensions, according to the phases of activity and rest in mice.
This fluctuation disappears when the normal biological rhythm is reversed. The disruption of our circadian clock probably has important repercussions on our liver functions.
Mammals have adapted to diurnal and nocturnal rhythms using a central clock located in the brain.
The latter, which is resettled every day by the light, synchronises the subordinate clocks present in most of our cells.
In the liver, more than 350 genes involved in metabolism and detoxification are expressed in a circadian fashion, with a biological rhythm of 24 hours, researchers said.
“Many of them are also influenced by the rhythm of food intake and physical activity, and we wanted to understand how the liver adapts to these fluctuations,” said Ueli Schibler, professor at the Department of Molecular Biology of the UNIGE.
The mice forage and feed at night, while the day is spent resting. “In rodents following a usual circadian rhythm, we observed that the liver gradually increases during the active phase to reach a peak of more than 40 per cent at the end of the night and that it returns to its initial size during the day,” said Flore Sinturel from UNIGE.