Resetting Our Biological Clocks

To all bits of clockwork that are adjusted in our bodies according to our day-night timetable, we can now add two more: cancer growth and the schedules of our internal complements of bacteria.

Cancer, according to a new Weizmann Institute study, may grow and spread more at night. In this scenario, our cells are getting messages left and right, day and night, and taking them in through the specialized receptors on their outer membranes. During the daytime, our bodies produce natural “wake-up” hormones, and these apparently, take precedence over other incoming messages, their receptors overriding those receiving growth factor messages. At night, when the wake-up hormones have gone to bed, the growth receptor messages are heard in the cell loud and clear, especially in cancer cells that tend to amplify growth signals.

The message: Certain anti-cancer drugs that target the growth factor receptors could be more effective if given at night.

How does a population of internal bacteria, which sit in the deepest intestinal dark, tell day from night? The scientists who brought us the news on the connection between artificial sweeteners, gut bacteria and glucose intolerance are back with a new study on our close relationship with our microbiome. This time, they have shown that our gut bacteria change and adapt throughout the day in synchronization with our eating schedule. So jet lag, for example, does not just screw with your head; it can temporarily upset the balance of bacteria in your gut. And constant upsets in that balance, as we know from their previous study, can lead to metabolic disorders. Indeed, the gut bacteria from a jet-lagged person implanted in the intestines of a sterile mouse caused weight gain and a rise in blood sugar levels.

The message: If you are gaining too much weight while rotating through shift work or flying around the world, blame it on your gut bacteria. Eventually, according to the scientists, we might be able to develop ways of “tricking” our gut bacteria into revising their schedules to fit the unnatural ones we adopt.