Flying in another time zone or working graveyard shifts messes up with our circadian rhythms and ultimately triggers a slew of health problems. Research suggests that one in five people living in Western countries who work at odd hours are putting their lives at risk since their schedule has been linked to obesity, diabetes, heart disease, even cancer. Now, a new study suggests delaying meals can delay metabolic functions governed by the biological clock, too. The work suggests that changing meal times, coupled with light exposure, can help synchronize the 'clock' and reduce health problems.
The notion that our bodies' biology runs in cycles known as circadian rhythms -- also known as sleep/wake cycle or body clock -- is becoming more and more established. This complex timekeeping system is controlled by an area of the brain that responds to light, which is why humans are most alert while the sun is shining and are ready to sleep when it’s dark outside.
Humans don't have a single body clock but a complex network of clocks -- as many as there are cells in the body. In mammals, all of these 'clocks' are synched with a master clock which beats by the rhythm set in a region of the brain called the suprachiasmatic nuclei (SCN) but also with peripheral clocks found elsewhere, like in various other organs.
It's the circadian rhythm that ultimately influences sleep-wake cycles, hormone release, body temperature and other important bodily functions. That's why disrupting this biological clock can come at a hefty cost to our health. Sometimes, though, such situations are inevitable, like in a work setting -- what to do?
Previous research has established that there's a link between nutrition and the circadian rhythm but it's only recently that this connection has been traced out in broader detail. Researchers at the University of Surrey in the UK recruited ten healthy volunteers who were fed three meals a day at exactly the same times every day for five days. After this initial round, the researchers delayed each meal time by five hours on the following six days. Each daily meal was identical in caloric and macronutrient content and at the end of the six days, the volunteers had to stay awake for 37 hours. They had small, identical snacks every hour for sustenance and dim lighting, in order to measure any change in their circadian rhythms.
These shifts caused a change in the cycle of blood sugar levels.
"A 5-hour delay in meal times causes a 5-hour delay in our internal blood sugar rhythms," said Jonathan Johnston, one of the authors of the new study published in Current Biology. "We think this is due to changes in clocks in our metabolic tissues, but not the 'master' clock in the brain."
Later, the authors found that the way a certain clock gene released instructions in white fat tissue was delayed after the shift in meal times. Seeing how the 'master clock' wasn't affected, the researchers reckon the delayed meals caused changes in the peripheral clocks without affecting the master clock.
Most jet lag and shift work therapies revolve around controlling light exposure but this sort of intervention seems to work on the master clock only. Changing meals, on the other hand, can help the peripheral clocks come up to speed as well, thus reducing desynchronisation of the body's clocks.
Keep in mind, though, that this was a small study which needs more validation before we can draw sound conclusions. It does suggest, however, that delaying breakfast for a couple of hours if you flew from London to Moscow can help. Nothing seems to beat a whole week camping under the stars, though.
