Sleep and health are intertwined. Getting enough sleep brings rest and recovery, leaving a feeling of alertness and being recharged, and has impacts on overall health and well-being. Sleep deficiency brings fatigue and is associated with a variety of physical and mental health problems, according to the Sleep Foundation.
The inability to get enough quality sleep is linked to an increased risk of obesity, heart problems, insulin resistance, immune imbalance, reduced cognitive function, memory issues, poor mood, and problems with growth and development.1
The circadian rhythm, part of the body’s internal clock, is known to promote high-quality, restorative sleep. However, as explained by the Sleep Foundation, if the circadian rhythm is thrown off, it can lead to poor sleep and sleep issues such as insomnia.
It’s previously been thought that the circadian rhythm is largely controlled by the brain, but research from the University of Queensland (UQ) has revealed that the liver influences the body’s internal circadian clock, which provides yet another reason to look after liver health.
Associate Professor Frédéric Gachon from UQ’s Institute for Molecular Bioscience, Dr Serge Luquet from Université Paris Cité/CNRS in France and their collaborators have demonstrated that mice with transplanted human liver cells had modified circadian rhythms.
Dr Gachon says the circadian internal body clock controls most biological functions, including sleep, hormone secretion, body temperature and metabolism.
“Mice are nocturnal, but when their liver cells were replaced with human cells, their circadian clock advanced by two hours – they ate and slept at different times to mice without those transplanted cells,” he said.
“The mice in our study started to eat and be active before night-time began, which is very unusual for a nocturnal animal.”
Until now, the synchronisation of the mammalian circadian rhythm was thought to be controlled exclusively by a central circadian clock composed of a group of brain cells called the suprachiasmatic nucleus.
Dr Gachon says this study shows human liver cells in a mouse can act on the central clock and modify circadian behaviour.
“Liver disease and metabolic diseases such as diabetes and obesity are associated with disrupted sleep, irregular eating and a disturbance of the circadian clock,” Dr Gachon said.
“This study suggests that the abnormal liver function is likely driving this disturbed rhythm.
“Our study deepens our understanding of the hormonal and neuronal mechanisms involved in the role of the liver in controlling circadian rhythms.
“It suggests that restoring liver physiology could benefit the health and well-being of patients.
“It also shows that the regulation of circadian rhythms is more complex than we suspected and presents avenues for investigating potential new treatments for metabolic diseases.”
The study was published in Science Advances. To read the study, visit: science.org/doi/10.1126/sciadv.adf2982
This feature was originally published in the July issue of Retail Pharmacy magazine.