Fat cells in the human body have their own internal clocks and exhibit circadian rhythms affecting critical metabolic functions, new research in the journal Scientific Reports, finds.
Researchers led by Dr Jonathan Johnston from the University of Surrey conducted the first ever analysis of circadian rhythms in human fat taken from people isolated from daily environmental changes.
During the study participants underwent regulated sleep-wake cycles and meal times before entering the laboratory, where they maintained this routine for a further three days. Participants then experienced a 37- hour ‘constant routine’ during which time they did not experience daily changes in light-dark, feed-fast and sleep-wake cycles. Biopsies of fat tissue were taken at six-hourly intervals and then followed by an analysis of gene expression.
Researchers identified 727 genes in the fat tissue that express their own circadian rhythm, many carrying out key metabolic functions. A clear separation in gene rhythms was identified, with approximately a third peaking in the morning and two thirds in the evening.
Dr Johnston said, “This is the first time that we have been able to identify such rhythms in human fat. This provides us with more information about how human metabolism changes across the day and possibly why the body processes foods differently during day and night.”