Your Gut on Travel

Virtually the whole human body is colonized by microbes. The gut―which refers to the gastrointestinal tract―is a particularly important reservoir, hosting trillions of microscopic organisms that include bacteria, viruses, fungi, and parasites.

While we’ve been taught to fear many of these microbes, they’re essential to our health. Our gut biome plays a key role in metabolism, hormonal regulation, brain function, and immunity, containing over 70 percent of our immune cells.

Laura Nicholas, ND, owner of Luna Health Clinic in Vancouver, says that many patients consider the impact of gut dysbiosis―an imbalance in the gut microbiome―as limited to digestive complaints. However, the effects can be far more wide-ranging. An imbalance of gut bacteria can contribute to mood disorders like anxiety and depression.

The gut microbiome also regulates inflammation, a key driver of chronic disease. According to Nicholas, gut dysbiosis can also play a role in health conditions like polycystic ovarian syndrome (PCOS), endometriosis, Hashimoto’s thyroiditis, bladder pain, and premenstrual disorders.

Your gut at 35,000 feet

Travel can put the gut biome under stress, particularly if you’re travelling by air.

While air in your home might have 40 to 60 percent humidity, the conditioned air entering an airplane cabin at cruising altitude is extremely dry. Lower levels of humidity can contribute to dehydration, which can disrupt your gut balance by encouraging the growth of microbes and reducing the number of immune cells.

Bloating and constipation are other common airplane complaints. As cabin pressure falls, trapped gas can expand in volume by 30 percent, causing discomfort and flatulence. Sitting still for hours on end can slow the movement of food through your gut, compounding issues of constipation and bloating.

Other travel troubles

Arriving at your destination can pose additional challenges for your gut. “Irregular eating patterns, unfamiliar foods, dehydration, stress, and altered sleep-wake cycles all influence digestive function,” says Nicholas. “Even without contracting an infection, many people report changes in bowel habits―most commonly constipation―with travel.”

Many people will also be (unfortunately) familiar with traveller’s diarrhea, which can affect up to 40 percent of travellers. It’s usually acquired through contaminated food or water, and while it usually resolves without lasting impact, it can also trigger conditions such as post-infectious irritable bowel syndrome (PI-IBS).

Guard your gut

There are proactive steps you can take to protect your gut health, both before and during travel.

Start early

Give your gut a head start by focusing on nutritious meals and taking good care of yourself before takeoff. “Supporting gut health while travelling starts with planning ahead,” says Nicholas. “I recommend focusing on whole, minimally processed foods, staying hydrated, and avoiding excessive alcohol or sugar, which can impair microbial diversity and suppress immune system function.”

Superstar supplements

A good-quality probiotic can help to improve the balance of good bacteria in your gut and boost your immune activity prior to travelling. Nicholas also recommends Saccharomyces boulardii, a type of probiotic yeast that can protect against traveller’s diarrhea and bacterial infections.

Nicholas also recommends taking digestive enzymes with extra hydrochloric acid (also known as stomach acid) to help adjust to unfamiliar cuisines and prevent pathogenic or opportunistic microbes from disrupting your gut balance.

To prevent constipation, Nicholas recommends magnesium citrate, which functions as a gentle laxative to help draw water into the gut. Supplementation with melatonin can also help to regulate your circadian rhythm when changing time zones. “This helps to get a longer and deeper sleep, which can support the immune system and prevent contracting an infection.”

Drinking elderberry juice may also help increase your ratio of beneficial gut bacteria, and ginger can help ease nausea if you do come down with a bug.

Healthy habits

During your trip, Nicholas recommends maintaining light physical activity, such as walking or stretching, which can help with digestion. Regulating your sleep and meal times as quickly as possible will also help to keep you regular.

In flight, try to avoid carbonated drinks, which can increase bloating. Since digestion slows down when you’re spending so much time sitting down, look for easy-to-digest meals with fibre, lean proteins, and healthy fats.

Think big

Being a human means existing in relation to millions of invisible organisms around and inside of us.

This means that travel can bring new places quite literally into your body: research shows that even travellers who don’t experience gastrointestinal distress can return home with a temporarily altered biome. These fluctuations are part of being alive―but with a bit of care and planning, you can make sure your gut stays balanced no matter where life takes you.

This article was originally published in the November 2025 issue of alive magazine.