Thinking about travelling this summer to Bali or French Polynesia? Maybe, while you’re reading these lines, you picture yourself lying on a beautiful beach, drinking smoothies, sunbathing and taking dips. Sounds good, really good. But, beware the health problems caused by jetlag during the days after your flight.
Scientists took faecal samples before and after the travel (or mock travel) to see which bacteria were thriving in their guts, and they found that not only did the gut bacteria composition change, but also the microorganisms that prospered under the changing conditions were the ones most associated with obesity, and other health problems.
The researchers even transplanted stool from the jetlagged humans into mice without gut microbes and found those mice gained more weight and body fat and had higher blood sugar levels compared to mice that received stool from the individuals before being jetlagged.
If you take a flight once a year to go on your summer holidays, the fact that your gut microbiota change may not be a big deal, apart from the inconvenience of feeling dizzy for some days or having some intestinal discomfort. Because luckily the effects of jetlag on the composition of gut microbiota dissipate within a few weeks. But if you have to travel often, crossing the planet or changing time zones, or you are a shift worker or an airplane pilot, then you may have a problem, as alterations in gut microbiota composition are linked to obesity, diabetes and other health problems. This could be related to why frequent travellers often pack on extra pounds.
Jetlag is also associated with gastrointestinal problems, such as diarrhoea or constipation, due to the change of diet (enjoying the native food) and eating at different hours in order to adapt to the new time zone, although maybe they are more linked to fact of the travel than to the sleep disturbances due to jetlag.
Cristina Sáez Cristina Saez is a freelance science journalist. She works for several media, for instance the Spanish newspaper La Vanguardia, where she coordinates the science section, Big Vang; as well as research centres and scientific societies. She has been awarded for her journalistic work, among others, with the Boehringer Ingelheim Award in Medical Journalism 2015. Follow Cristina on Twitter @saez_cristina