According to clinical nutritionist Stephanie J Moore it’s all down to the micro-organisms that inhabit our digestive tracts: “One of the more recent findings relating to gut health and travel is the way it disrupts our gut microbes on a number of different levels, which results in people experiencing irregular bowel movements and just feeling a bit sluggish, bloated and generally ‘ick’.”
Grumpy gut
I have made peace with bloating after 46 years around the sun, but it is this “irregularity” – which Moore notes can range from constipation to frequent, loose stools (not to be confused with travellers’ diarrhoea, which is due to a pathogen rather than microbial upset) – that has marred my travel experience.
While most people’s holiday anxieties may centre around switching off sockets or misplaced passports, mine have been dominated by what toilet facilities will be available en route. But why is my gut so grumpy when it comes to holidays?
“What wasn’t appreciated until fairly recently is that our gut microbes have their own circadian rhythm,” says Moore, “so changing time zones disrupts their function as much as it does our sleep.”
According to Moore, these clever critters take on totally different roles at different times of the day: “During the day there’s the process of digestion and detoxification of the food moving through the intestinal tract, whereas at night their function switches to housekeeping mode in order to prepare it for food the next day; killing off nasties and cleaning up the mucus membrane that lines the intestinal wall where the microbes (and immune cells) live, which in turn keeps the immune system healthy.” It stands to reason that moving from GMT to CST (or even just “Ibiza time”, aka eating at 11pm) is going to confuse the little blighters.
Modern stresses
Factor in some “it’s 12pm somewhere” booze that many of us start downing before we even buckle up – unsurprisingly alcohol is microbe-toxic – plus processed food and the stress of modern-day travel (airport security is enough to induce a bout of Delhi belly) and we’ve already got the beginnings of an unhappy microbiome. “Another thing that gut microbes really don’t like is changes in atmospheric pressure,” adds Moore, something Dr Megan Rossi, aka the Gut Health Doctor, refers to as “mile-high IBS”.
“There’s a reduced oxygen level, which changes the function of intelligent organelles inside our cells called mitochondria,” explains Moore. “Whilst we used to think of them simply in terms of making energy, we now realise they do a lot more and when the systems are disrupted, they go from making lots of energy to putting the brakes on.” The result being that wiped-out feeling we often experience on flights, as well as our digestive tracts slowing down and making us more constipated and stagnant.
So far so bad, and that’s before you’ve even reached the gluten/lactose-fest that encapsulates a typical holiday diet (interestingly Moore notes that we often tolerate bread on the continent better as it tends to be less processed, contains better quality flour and, in the case of French baguettes, has been proved – or fermented – for at least 24 hours, making it more gut-friendly).