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When you eat is just as important as what you eat, research shows

Researchers from the Medical Research Council have found evidence to suggest the importance of timed meals in regards to health.

The team is the first to establish that insulin is the primary signal that communicates timing of meals to individual “cellular clocks” within our body, together known as the body clock, or circadian rhythm. Knowing this may be the key to helping those experiencing disruption to their body clocks.

Our individual body clocks are synched to the environment around us by way of exposure to daylight and meal times. It’s this synchronization that is vital to maintaining health, and can be thrown out of whack if traveling through different time zones or eating at irregular times throughout the day.

Although it’s known that irregular meal times can disrupt the body clock, how the body clock senses and responds to meal timing was an unknown. So, scientists from the MRC Laboratory of Molecular Biology (LMB) and the University of Manchester used cultured cells and mice to identify insulin, a hormone that is released when we eat, as the primary sensor and communication between our cellular clocks. Furthermore, insulin adjusts the circadian rhythm in individual cells and tissues by stimulating production of a protein called PERIOD.

“At the heart of these cellular clocks is a complex set of molecules whose interaction provides precise 24-hour timing,” lead researcher Dr. John O’Neill said. “What we have shown here is that the insulin, released when we eat, can act as a timing signal to cells throughout our body.”

The team found that when the mice’s insulin was released at the “wrong” time, that is, when the mice should have been resting, it disrupted their circadian rhythms, thus making it more difficult for them to tell the difference between day and night.

“We already know that modern society poses many challenges to our health and wellbeing — things that are viewed as commonplace, such as shift-work, sleep deprivation, and jet lag, disrupt our body clock,” said Dr. David Bechtold, a senior lecturer at the University of Manchester. “It is now becoming clear that circadian disruption is increasing the incidence and severity of many diseases, including cardiovascular disease and type 2 diabetes.”

“Our data suggests that eating at the wrong times could have a major impact on our circadian rhythms,” said lead author Dr. Priya Crosby. “There is still work to do here, but paying particular attention to meal timing and light exposure is likely the best way to mitigate the adverse effects of shift-work. Even for those who work more traditional hours, being careful about when we eat is an important way to help maintain healthy body clocks, especially as we age.”

The findings were published in Cell.

By Olivia Harvey, Staff Writer

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