Jet lag doesn’t just leave us feeling fuzzy-headed and hung-over, it can also affect our internal organs in a phenomenon known as ‘gut lag’. By now you’ve probably heard of the gut microbiome – the trillions of bacteria or microbes that live, breed and snack on your intestinal tract. The idea is enough to make your skin crawl, but they play a key role in everything from our mood to our sex drive and energy levels. Given most of your immune system is located in the gut, these microbes also help to fight viruses and infections so it goes without saying that keeping them happy and in balance is important.
What we didn’t know until recently, though, is that jet lag can throw these gut microbes out of whack. It seems there’s a complex interplay between our brain, our gut and its own daily rhythms, and hopping from one time zone to another is the reason you wake up at 4am craving a cheeseburger, while nastier side effects can include constipation and diarrhoea.
What is gut lag and what causes it?
Put simply, “gut lag describes the disrupted rhythm of internal organs such as the liver and gastrointestinal tract as a result of traveling across two or more time zones,” says Shabir Daya, pharmacist at Victoria Health.
Long-haul flights essentially cause sudden shifts in your normal sleep-wake cycle upon landing. As well as feeling groggy, your gut health is thrown out of kilter because its schedule is controlled by a part of the brain that relies on light and dark to maintain its daily routine. “All our glands work in a rhythm governed by the circadian clock, which can get disrupted when we travel through time zones,” says Shabir. “Not eating at the usual time can cause a loss of appetite or make us feel extra hungry at the time when we’re supposed to eat back at home.”
In addition, there is evidence that traversing different time zones and disrupting the circadian rhythm may also have a knock-on effect on the bacteria in the gut responsible for immunity and digestion. According to Dr Sammie Gill, dietician at probiotic brand Symprove, “this is because your gut microbes sync with your body clock, so sudden shifts in your normal sleep-wake cycle can result in shifts in the microbiome landscape, too.”
Gut specialist and clinical nutritionist, Nishtha Patel concurs. “We’re creatures of habit,” she says. “The body has an internal 24-hour clock, which keeps all of our bodily functions moving correctly and on time. Our gut microbiome supports these functions and it also plays a role in our circadian rhythm by producing the hormone melatonin, which is responsible for our sleep-wake cycle.”
So it’s no wonder that any changes to daylight hours causes the gut to become slower – hello gut lag in the form of bloating, lethargy, constipation and even an upset stomach.
How can you treat gut lag?
One option is to anticipate issues with your gut and take a few simple preventative measures. Start taking a probiotic – live ‘good’ bacteria and yeasts that keep your digestive system balanced – a week before, during and after your flight.