Individuals who fly and suffer from jet lag regularly may be a risk of health issues like breast cancer, diabetes, heart attack and obesity. This could be due to microbes in the gut that increase these health issues. In 2011, a study showed that if one works shifts for a decade or longer, the chances of being diagnosed with type-2 diabetes increases by nearly 40 percent. The journal Cell recently looked into this to find out why.
In Israel, Weizmann Institute of Science immunology department senior scientist Eran Elinav, MD, PhD, looked at the gut micro biome, which he suspected was the culprit. Elena refers to the gut a neglected, or overlooked organ. He feels the gut may suffer from a disrupted circadian rhythm. However, that was not the obvious choice to look at. With no changes of light, only darkness, the microbes live in the dark region of the gut. The microbes never are exposed to direct light and never see a cycle of day and night. By not seeing these changes, it was amazing to discover that the microbes were in fact affected by changes to an individual inner clock.
Using mice at first, Elinav had the rodents “work” a graveyard shift. Elena placed the mice in a situation that was similar to jet lag of about 8-hours for a human. Mice are a nighttime creature, so, Elinav forced the critters to stay awake during the day. The result in the microbes was amazing to Elinav. While the mice appeared to be “jet lagged” the microbes in the rodents guts were messed up. The bugs function and composition changes and they lost the normal circadian rhythm. The microbes also were less efficient at normal tasks like DNA repair, detoxification and cell growth.
Similar to human beings, the microbes in mice are like housekeepers, repairing the functions inside the body while the “host” typically sleeps. While the host is awake, the microbes provide growth and functions that promote energy in individuals. The jet lagged mice indicated that without the proper sleep cycle, they performed tasks at a much lower level than normal schedule rodents.
It was also discovered that the mice were more prone to be obese and become diabetic. Transferring the jet lagged mice gut bacteria into healthy, clean mice, Elivan discovered that those mice were then more likely to become obese or diabetic. Elivan believes this proves that the microbes drive this.
Proving this in humans is a much harder test. Elinav studied a pair of individuals flying from the U.S. to Israel. With the people suffering from a similar 8-hour jet lag, he sampled the microbes from their guts. He took samples three times over a two-week period. This allowed him to catch the main stage of the jet lag. Elinav discovered that the microbes in the human had indeed changed their composition and were displaying similar changes to the jet lagged mice. The research scientist also transferred some of the human microbes into the mice to see if at the height of the jet lagged period for the humans would result in more intolerance towards glucose and become more obese.
The microbes in the guts of the travelers returned to normal function about two weeks after arriving in Israel. However, for frequent travelers, the changes to the microbes and not giving the body a chance to catch up could lead to an increase chance of obesity or diabetes, or both. Keeping a healthy sleep pattern and giving the body a chance to recover from major changes like jet lag is one way of keeping the microbes in the gut from leading towards obesity and diabetes.
By Carl Auer