Washington DC

A recent study suggests that eating time is important knowledge for the human body which impacts the health of people. Furthermore, researchers identified insulin as a primary signal that helps communicate the timing of meals to the cellular clocks located across our body, commonly known as the body clock.

The team behind the research believes this improved understanding may lead to new ways to alleviate the ill-health associated with disruption to the body clock.

The body clock – also known as the circadian rhythm – is a 24-hour biological cycle that occurs individually in every cell of the body, driving daily rhythms in our physiology, from when we sleep, to hormone levels, to how we respond to medication according to the study published in the Journal of Cell.

Our body clock is synchronised with the surrounding environment by exposure to daylight and the timing of meals. This synchrony is important for long-term health, and it is well known that disrupting your circadian rhythm by shift work or travel across time zones can be detrimental to health.

Importantly, it is thought that eating at unusual times, as often occurs during shift work and jet lag, is a major cause of body clock disruption.

However, it has not previously been known exactly how the body clock senses and responds to meal timing, making it difficult to provide medical advice or interventions that might alleviate the problem.

Researchers have now identified insulin as a primary signal that helps communicate the timing of meals to the cellular clocks across our body, and in doing so strengthen the circadian rhythm. The team’s experiments in cultured cells, replicated in mice, show that insulin, a hormone released when we eat, adjusts circadian rhythms in many different cells and tissues individually, by stimulating the production of a protein called ‘period’, an essential cog within every cell’s circadian clock.

Dr John O’Neill, the lead researcher, said: “At the heart of these cellular clocks is a complex set of molecules whose interaction provides precise 24-hour timing. 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 researchers found that when insulin was provided to mice at the ‘wrong’ biological time – when the animals would normally be resting – it disrupted normal circadian rhythms, causing less distinction between day and night.

Dr Bechtold, a researcher said: “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. It is now becoming clear that circadian disruption is increasing the incidence and severity of many diseases, including cardiovascular disease and type 2 diabetes.”

Dr Priya Crosby, the lead author, highlighted: “Our data suggests that eating at the wrong times could have a major impact on our circadian rhythms. 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.”