Overindulgence during this feasting season can play havoc with the human body’s food clock, researchers from the University of California, San Francisco reported in PNAS (Proceedings of the National Academy of Sciences).
Overeating, changing sleeping patterns, and significant changes in eating habits over the holiday period can upset the body’s “food clock”, a collection of genes and molecules that interact with one another and keep the human body on a metabolic even keel. The UCSF scientists inform that their new study helps reveal how this clock functions on a molecular level.
If our eating habits change, PKCy, a protein, is crucial in resetting the food clock.
Louis Ptacek, MD. and team showed that lab mice which were given food during their sleeping hours will eventually adapt their food clock and start waking up at the “sleep time feeding time”, and run around in anticipation of food. However, mice which do not have the PKCy gene never adapt, and continue sleeping right through their sleep-time meal.
A desynchronized food clock may be associated with the pathology underling certain diseases and disorders, such as metabolic syndrome, diabetes and obesity, the authors explain. They added that their study has implications for understand the molecular bases for such conditions.
Dr. Ptacek wrote that this may also explain why obesity is more common among “night-owls” than “morning larks”.
Dr. Ptacek added:
“Understanding the molecular mechanism of how eating at the “wrong” time of the day desynchronizes the clocks in our body can facilitate the development of better treatments for disorders associated with night-eating syndrome, shift work and jet lag.”
Biological clocks are as complicated as mechanical clocks. Behind a mechanical clock one can find flywheels, cogs, reciprocating counterbalances and several other moving parts. Biological clocks consist of many interacting genes that switch on or off in an orchestrated way to keep time during each 24-hour period.
In the majority of living beings, biological clockworks depend on the circadian oscillator (a master clock) which keeps track of time and coordinates the body’s biological processes with the rhythm of a 24-hour day and night cycle.
Master clocks exist in most life forms, including mustard greens, mice and humans. Over the last ten years, scientists have discovered many of their inner workings, and identified several genes whose cycles are linked to the clock. They have discovered how in mammals, our circadian rhythms are controlled by a tiny sport in the brain, called the “superchiasmatic nucleus”.
The researchers know that apart from the master clock, human bodies have other clocks which operate in parallel throughout the day. The food clock is one of these – it is not tied to one specific spot in the brain, but rather several sites in different parts of the body.
The food clock helps our bodies make the most of what we eat. It regulates the genes that are involved in everything, from absorbing nutrients in our intestines to their dispersal in the bloodstream. Our food clock is designed to anticipate our eating patterns.
Even before we start a meal, our bodies start turning on some of these genes and switching others off, in preparation for a burst of nutrition. This is why we get bouts of hunger as our eating times approach.
Experts have known that if our eating patterns change, our food clock can be reset. If we eat at odd times or to excess, the food clock adapts. However, it was not until very recently that scientists understood how the food clock operated on a genetic level.
Dr. Ptacek and team discovered how the food clocks work at a molecular level. PKCY binds to BMAL, another molecule, and stabilizes it, resulting in a shift in the clocks timing.
Written by Christian Nordqvist