(Insert dream destination here) has been on the top of your travel bucket list for years, and you are finally fulfilling your fantasy. You’ve wanted to go there to experience something totally novel—a new country, culture, and cuisine. You are on a quest to step out of your comfort zone, broaden your horizons, and have a meaningful and memorable experience. The idea is to both lose and find yourself in the thick of tantalizing tastes, smells, sights, and sounds. This is what travel is all about.
What you don’t want, though, is constipation, bloating, lethargy, and traveler’s diarrhea. While you might be over the moon about a trip overseas, your gut might physically display a different sentiment.
Travel can be impactful on many different levels, including on our gut microbiome. And as we are beginning to realize (scientifically and societally), everything seems to be connected, controlled, or influenced by our gut, including the majority of our immune system.
The Role of the Gut Microbiome in Traveler’s Health
The primary functions of the gut microbiome involve immune system education and enforcement, metabolic processes, and protection against harmful, foreign pathogens. These are all operations you want in tip-top working order during your international escapade. For many, this is not the case, though. Upward of 100 million people travel from industrialized countries to developing countries every year. Of those 100 million travelers, between 40-60% will develop traveler’s diarrhea (TD). Various pathogens are known to cause TD, including but not limited to bacteria such as Escherichia coli and Salmonella, Shigella viruses, and parasites like Giardia.¹
Interestingly, the gut microbiome of a traveler suffering from TD is very similar to that of an individual experiencing gut disharmony (characterized by a high abundance of bacteria in the phylum Firmicutes, an increase in Proteobacteria, and few members of Bacteroidetes).² Part of your gut microbiome’s natural protective function involves creating and maintaining a barrier against incoming pathogens, such as those that contribute to TD.
When your microbiome is out of whack, its ability to perform all its health-sustaining functions, including keeping us from getting sick, is greatly compromised.
What Happens to Your Gut When You Travel
Your gut loves fiber and consistency. Like all living organisms, the microbes in your gut have specific dietary needs and their own biological clocks that dictate life processes similar to ours, and many of which benefit their host (you). Whether we are conscious of it or not, we ask a lot of our gut, but our gut doesn’t ask very much of us. Unfortunately, though, many of us aren’t the best hosts, and the result is evident in the prevalence of gut-rooted health concerns commonly found in industrialized countries like the United States—our diets are too high in fat and refined sugar and too low in fiber; our sleep-wake cycles are inconsistent; we are too sedentary; we are chronically dehydrated.
Now, to really shake things up, we take our gut across seas and into new time zones where any semblance of routine is thrown out your hotel window and indulgence levels are high (Bonjour, afternoon wine! Hola, chorizo! Namaste, butter chicken!).
Our current gut microbiome baseline (this is something you can test for) before we travel can make us more susceptible or more resilient against gastrointestinal upsets and gut drama while abroad, as it can while we are home too. When we travel, though, we are more prone to rhythmic disruptions, dietary changes, and novel exposure to different types of bacteria, fungi, and parasites that can affect our unique microbial community.
Rhythmic Disruption
Scientists have discovered that our microbial community depends on consistent rhythms to function optimally.³ We have also learned that there is a shift in the quantity of Bacteroidetes and Firmicutes in our gastrointestinal tract from day to night.⁴ So, in short, our sleep-wake cycle directly impacts our gut composition. Travel can disrupt your normal rhythms (sleep-wake and fast-eat cycles) and, in turn, disrupt your microbiome by reducing the number of healthy microorganisms and increasing the population of potentially harmful microorganisms.
Travel tips: Leading up to your trip, dial in your circadian rhythm. Making sure you are going to sleep and waking up at the same time each day and that your sleep window is sufficient in length will help ensure your gut microbiota is happy and healthy before you travel. During your trip, try your best to maintain your regular sleep pattern.
Dietary Changes
Diet is one of the most impactful factors contributing to gut health. Two things tend to happen when we travel. One, we ditch our regular home diet, and two, we introduce new foods into our temporary travel diet. As stressed earlier, our guts don’t love change unless that change is favorable to them, such as adopting a high-fiber diet, drinking more water, and adding a personalized prebiotic and probiotic into the mix.
Tasting the local fare is part of experiencing the culture of a place, though. However, introducing new types of food, preparation methods, and spices should be done gradually and with elevated attention to sanitation practices (if the water isn’t safe to drink, foods washed in that water aren’t safe for you to eat either).
Travel tips: Be mindful of any types of foods or spices that would normally cause discomfort. Take a fiber supplement.
Novel Exposure
Each environment or region has its own unique microbial strains. In fact, your environment greatly influences your gut microbiome diversity. Geographical and racial variations in microbiome structure can be attributed to host genetics, innate/adaptive immunity, diet, hygiene, parasite load, and environmental factors, among other influences like age, gender, and medication use.⁵
Our microbiome wants to prevent and limit foreign pathogen colonization, but when we are traveling, this can be difficult to do. Pathogens get in via the food, water, air, and surfaces we come into contact with as we explore and experience a new destination. Observational studies have shown that even if you don’t get TD or some other traveler’s malady, your gut composition may be altered just by traveling.⁶
Don’t worry, though; the change isn’t necessarily permanent. The gut will find a way to stabilize itself over time. In one study, a traveler from the United States who spent 51 days in a major city in Southeast Asia showed a dramatic change in their gut composition while abroad. However, within two weeks of returning home, the microbiota returned to its pre-travel composition.⁷
Travel tip: Follow traveler advisories/recommendations for food and water. There are a lot of places where it is not advised to drink the tap water or eat raw fruits and vegetables (especially with the skin on). Know before you go!
Bonus tip: If it is not already part of your wellness routine, take probiotics while you are traveling to help support your immune and digestive systems while abroad.*
Is Travel Good for Your Gut?
The short answer is—ultimately, yes. While exposure to certain types of pathogens can harm your health, exposure to different types of microbes can make your gut more resilient. As we have shifted in our human history from hunting and gathering to rural farming to industrialized urban living, we have lost some of our microbial diversity along the way. Diversity is what creates resilience, though, and resilience is necessary for sustained health.
Resources:
Youmans, B. P., Ajami, N. J., Jiang, Z.-D., Campbell, F., Wadsworth, W. D., Petrosino, J. F., DuPont, H. L., & Highlander, S. K. (2015, February 19). [The gut microbiome during travelers' diarrhea]. Gut microbes. Retrieved November 25, 2022, from PubMed Central.
Youmans, B. P., Ajami, N. J., Jiang, Z.-D., Campbell, F., Wadsworth, W. D., Petrosino, J. F., DuPont, H. L., & Highlander, S. K. (2015, February 19). [The gut microbiome during travelers' diarrhea]. Gut microbes. Retrieved November 25, 2022, from PubMed Central.
Parker, J. (2022, March 25). [Preparing your gut for traveling]. Viome.com. Retrieved November 25, 2022, from viome.com
Frazier, K., & Chang, E. B. (2020, January). [The gut microbiome, circadian rhythms, and metabolism]. Trends in endocrinology and metabolism: TEM. Retrieved November 25, 2022, from PubMed Central.
Gupta, V. K., Paul, S., & Dutta, C. (2017, June 23). [Geography influence on human microbiome composition]. Frontiers in microbiology. Retrieved November 25, 2022, from PubMed Central.
Hassing, R. J., Alsma, J., Arcilla, M. S., van Genderen, P. J., Stricker, B. v H., & Verbon, A. (2015, November 26). [Review of International Travel and gaining of resistant bacteria]. Eurosurveillance. Retrieved November 25, 2022, from eurosurveillance.org
David, L. A., Materna, A. C., Friedman, J., Campos-Baptista, M. I., Blackburn, M. C., Perrotta, A., Erdman, S. E., & Alm, E. J. (2014, July 25). [Lifestyle affects on human microbiota]. BioMed Central. Retrieved November 25, 2022, from genomebiology.biomedcentral.com
