How to stop a stomach bug from ruining my holiday: Prepare your gut before take-off

Nothing ruins a holiday faster than becoming ill with a stomach bug. One minute you’re enjoying your beak abroad — the next, you’re stuck in your hotel room with the runs.

It’s very common: up to 50 per cent of people travelling abroad will be affected by a tummy bug, according to studies.

And symptoms, such as having three or more watery bowel movements a day, stomach cramps, fever, nausea or vomiting can cause days of misery.

The most common trigger is harmful bacteria from contaminated food or water.

These bacteria produce toxins that your intestines try to flush out, causing watery stools. Some bacteria, such as salmonella, invade your gut lining, causing inflammation, making it harder to absorb water and nutrients, resulting in diarrhoea.

Whatever the cause, the symptoms will usually clear within two to three days without any need for medical attention (although if you have diarrhoea that lasts for more than a week, or have blood in your stools, then it’s best to see a doctor).

But for some, traveller’s tum becomes more than a temporary inconvenience, as it can increase the risk of developing irritable bowel syndrome (IBS).

In fact, a review published in the journal Gastroenterology in 2017 found that 10 per cent of people who’ve had traveller’s tum go on to develop long-term iBS, with symptoms such as bloating, diarrhoea or constipation, and abdominal pain.

It’s thought this is because the infection causes inflammation in the gut and alters the balance of bacteria there, which means symptoms persist in the weeks and months after the infection clears.

All of which adds weight to the merit of prevention being better than a cure.

But apart from standard advice such as being cautious of tap water and ice (in case it’s made with contaminated water) and following the “boil it, cook it, peel it, or forget it” rule when it comes to fresh food, there are other strategies to prevent traveller’s diarrhoea while you’re on holiday.

Here are my prevention tips — plus, my advice on ways to quickly ease symptoms if you do fall ill, getting you back to enjoying your holiday sooner.

Boost gut bacteria

In the week before your trip think about getting your gut ‘travel ready’ — by which I mean getting your gut bacteria in good shape.

That’s because trillions of harmless bacteria and other microbes living in your large intestine — collectively known as your gut microbiome — can help prevent harmful invaders from colonising your gut and causing infection. They do this in multiple ways.

A study by Oxford University, published in the journal Science last year, found that having a healthy gut microbiome, with many different types of gut bacteria, blocks the growth of harmful bacteria such as salmonella by using up the nutrients they need to survive.

Your gut microbiome also interacts with your immune system — 70 per cent of your immune cells live in the lining of your gut.

And a healthy community of gut bacteria can help strengthen your immune system’s defences, making it easier for your immune cells to identify and combat harmful bacteria before they cause infection.

The good news is that it doesn’t take long to turn the health of your gut microbiome around — it can take as little as three to four days, according to a study published in the journal Nature in 2013.

Start feeding up your gut bacteria in the fortnight counting down to your holiday by focusing on eating more fibre — which good gut bacteria thrive on. Simple steps can help, such as ensuring half your plate is full of vegetables at lunch and dinner, and having nut and seed snacks.

Also try adding fermented foods to your daily diet, such as kefir (fermented dairy) which makes the basis of a great gut-friendly breakfast with wheat bran, berries, nuts and seeds.

Another fermented food to try is kimchi — a type of fermented cabbage with other vegetables — which works well as a side dish or used to add crunch to sandwiches.

Take a fibre capsule

For extra security, you may also want to take a daily supplement of a type of fibre, called galactooligosaccharide (B-GOS) that specifically feeds your ‘good’ gut bacteria.

For one study, 81 volunteers were given a daily sachet of 5.5g of B-GOS, to take starting the week before their trip and continuing for the duration of their holiday — 78 were given a placebo.

According to the results published in the journal Nature in 2009, those who took the B-GOS were 40 per cent less likely to get traveller’s diarrhoea than those who took a placebo.

What’s more, those who did fall ill had less stomach pain and recovered in half the time of the placebo group.

As well as feeding your ‘good’ gut bacteria, B-GOS is thought to create a protective barrier on the lining of your gut, preventing harmful bacteria from sticking to the gut’s surface and causing infection.

Similar compounds are found in soya beans, chickpeas and lentils and while it’s not known if eating these will have the same effects, they will add beneficial amounts of fibre to your diet.

You can buy B-GOS online or at most health food stores as a powder or capsule.

Freeze leftover fruit and veg

While it might seem practical to use up everything in the fridge before your trip, not buying fresh, perishable items such as fruit and vegetables can be counterproductive for your gut bacteria.

What’s more, it may make you more reliant on packaged, ultra-processed foods, which, if they make up a lot of your diet, can be bad news for the microbiome.

Instead, focus on fresh produce that lasts well such as root vegetables, or cook and freeze any food leftovers that won’t last. You can roast trays of veg with garlic and spices, or whizz into soup, before freezing.

Pack some fungi

This might sound unlikely but yeast could help both prevent and treat a stomach bug.

Alongside bacteria the gut microbiome contains fungi, including certain yeasts, and taking a yeast capsule may help with your immune defence by bolstering numbers.

A 2019 review of studies, published in the Journal of Travel Medicine and Infectious Disease, found that taking the probiotic yeast Saccharomyces boulardii CNCM I-745 (available in some supermarkets or health food shops) in the days before the holiday and while you are away, lowers the possibility of a stomach bug on holiday by 20 per cent.

And if you do get struck down with diarrhoea, a 2023 study published in BMC Gastroenterology found that taking Saccharomyces boulardii CnCM i-745 alongside paracetamol and an antispasmodic can help ease symptoms, such as stomach pain and fever, better than a placebo.

Try taking it for the week before and during your holiday.

Try banana remedy

The biggest danger if traveller’s diarrhoea does strike is dehydration. And because you will be losing not only fluid but also electrolyte salts, such as sodium, chloride and potassium that help your body’s fluid balance, water alone may not be enough to fully hydrate you.

Feeling weak or dizzy may be a sign that you are low in fluids and salts. While you can buy rehydration sachets or electrolyte drinks to help, you can make your own remedy by adding six teaspoons of sugar (to help speed up the rate your body absorbs water) and half a teaspoon of salt (to provide sodium and chloride) to a litre of water. To get in extra potassium eat a banana alongside this.

In terms of fluid, aim for 1.5 to 2 litres of fluids a day.

Lay off the ice cream

Even when you feel well enough to eat and drink as normal it’s worth being careful in the early days of your recovery until your system feels like it is really back to normal.

So steer clear of coffee as this can have a laxative-like effect, stimulating your gut to move food through quickly, as will decaffeinated coffee, although to a lesser extent.

the same goes for spicy food, as the capsaicin, which is found in spices such as chilli powder and paprika, can accelerate how quickly food moves through your gut.

You also might want to put your holiday ice cream on hold, as your gut isn’t able to fully digest lactose, the sugar in milk, when you have diarrhoea, and could make your symptoms worse.