We already know that the human body works all day. Our biological functions follow 24-hour cycles, or circadian rhythms, which are physiological and mental changes driven by our internal biological clocks. Now, an investigation carried out by experts from the Faculty of Health and Medical Sciences of the University of Surrey (United Kingdom), explains how we can reset one of these body clocks. With meal times.
Remember that circadian rhythms are controlled, in turn, by the so-called master clocks in our brains. This ‘master clock’ is nothing but a group of neurons that communicate with each other and that are located in an area of the brain known as the suprachiasmatic nucleus (NSQ for short), within the hypothalamus.
The SCN has approximately 20,000 neurons or nerve cells, and the area of the brain in which it is located (the hypothalamus) controls body temperature, hunger, and thirst.
Research has examined the effect of a 5-hour delay in meal times on the body’s master clock, as well as its various peripheral circadian rhythms.
Why choose food?
Although we know that circadian rhythms, human metabolism, eating patterns, and nutrition are interconnected, the link between meals and the circadian rhythm has not been sufficiently investigated.
Therefore, they gathered 10 healthy young people for an experiment that lasted 13 days. Participants were served three meals a day, spaced 5 hours apart, occurring either very early or much later after they had awakened. The first meal intervals began half an hour after waking up, while the later ones began 5.5 hours after that time. All the meals had the same nutritional content and the same number of calories.
The scientists measured the participants’ circadian rhythms in a 37-hour “constant routine,” which is a special research protocol that specifically allows scientists to measure a person’s circadian rhythm. It usually involves continuous bed rest under persistent lighting. In this case, the routine included dim lighting, equally spaced small snacks, reduced physical activity, and no sleep.
What happened?
In general, the delay in the timing of meals did not influence the appetite or sleepiness of the participants. The brain’s master clock was also unaffected , as its biomarkers – for example, melatonin and cortisol, and gene expression – remained unchanged. However, what did change significantly were the participants’ blood sugar levels. Late meal times slowed blood sugar rhythms by an average of 5 hours.
“ A 5-hour delay in meal times causes a 5-hour delay in our internal blood sugar rhythms . We believe this is due to changes in the clocks in our metabolic tissues, but not in the master clock in the body. brain. We expected to see some delays in rhythms after late meals, but the size of the change in blood sugar rhythms was surprising. It was also surprising that other metabolic rhythms, including blood insulin and triglycerides, did not change “explains Jonathan Johnston, co-author of the work.
Furthermore, they found that the rate of expression of a gene called PER2 was also delayed by 1 hour.
“Therefore, timed meals play a role in the synchronization of peripheral circadian rhythms in humans and may be of particular relevance to patients with circadian rhythm disorders, shift workers, and trans-meridian travelers,” the authors conclude.
Thus, people who regularly suffer from jet lag may try to eat at specific time intervals to help reset their internal clocks.
Referencia: Meal Timing Regulates the Human Circadian System. Sophie M.T. Wehrens, Skevoulla Christou, Cheryl Isherwood, Benita Middleton, Michelle A. Gibbs, Simon N. Archer, Debra J. Skene, Jonathan D. Johnston. Current Biology. June 2017. doi.org/10.1016/j.cub.2017.04.059 Open access funded by Biotechnology and Biological Sciences Research Council
