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.
A common cause of cramping and other distressing bowel symptoms.
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.”
The battle of bright-eyed bandits and bushy-tailed squad ends here…
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.
“Eat small meals, or nothing at all, while flying to prevent putting a burden on your digestive system which can cause indigestion, colic and gas to build in the intestines as a result of air pressure,” says Shabir, who also recommends drinking plenty of water (eight glasses a day is a good rule of thumb) as fluids keep everything moving through the gut and bowels. Nutritious snacks include wholegrain crackers with cheese, apple slices and peanut butter, or carrot sticks and bean dip, adds Dr Gill. In particular, avoid fruit and sugary foods. “The fructose from fruit can also cause a build up of gas so stick to just one portion 24 hours before you fly and also during your flight,” says Nishtha.
Set your watch before you travel and eat and sleep according to the new local time. “If it’s night-time at your destination, try and sleep on the plane; if it’s daytime stay awake or opt for a power nap and set an alarm," says Dr Gill. "Earplugs, a sleep mask and a travel pillow will help maximise comfort and encourage sleep even if your body doesn’t want to.”
While the temptation when you check into a hotel is to curl up in your duvet and snooze the day (and night) away, get outside in natural light to help your body clock and gut microbes to adjust. “This will tell the brain and body that it's waking hours and help with melatonin production to help regulate the gut,” says Nishtha. “Also set the alarm to the time you normally wake and go straight outside.” If you're struggling, download an app such as Timeshifter, which ‘resynchronizes’ your body clock with the new time zone through a personalised sleep, 'seek light' and caffeine schedule.
Equally important is to restore your gut to full function. “Go for a walk to kickstart the digestive system and drink plenty of fresh warm or room temperature water," Nishtha advises. "Try and eat a big green salad or other vegetables and fruits to get fibre into your system and get the bowels moving again," she adds.
The bottom line? There's no reason to panic. Unless you’re a frequent flyer, travelling for the odd holiday is unlikely to have any detrimental effects on your gut microbes, says Dr Gill. “Microbes tend to bounce back to their original state after a couple of weeks,” she says. "That said, it's worth doing things to keep them happy during travel and help them adapt to their new wake-sleep cycle."
