Studies suggest that an estimated 20 million people experience traveller's diarrhea each year, and it's miserable for everyone. In years past, people preparing for their epic trips would either cross their fingers, pack some over-the-counter antidiarrheal meds and hope for the best, or they might even convince their docs to fork over a prescription for antibiotics just in case. But recent research and the explosion in popularity of over the counter probiotic supplements is leading people to also try stocking up on probiotics in their travel bag, too. The question is: Do probiotics even really help for this?
Anecdotal evidence suggests that, yes, probiotics could possibly help treat and maybe even prevent diarrhea. "The idea that we could give someone something to bolster or strengthen the defenses of a travellers' microbiome to prevent bad bacteria from colonizing and causing illness is an attractive one," says Mark Riddle, MD, MPH, chair and professor of the department of preventive medicine and biostatistics at the Uniformed Services University. But studies so far on travellers haven't consistently shown any benefit, he says. So, probiotics aren't exactly a slam-dunk treatment for this specific type of diarrhea.
Traveller's diarrhea is really a bacterial infection. It's just like other types of diarrhea in terms of symptoms (loose or watery stool and abdominal cramps), but this particular type is triggered by consuming bacteria from contaminated food, water, or ice, Gina Sam, MD, MPH, a gastroenterologist and head of The Institute of Gastrointestinal Motility Disorders and Integrative Health in New York City told Refinery29. So basically, the idea is that these probiotics repopulate your gut with "good" or "normal" bacteria that can fight the icky bacteria that causes the acute bout of diarrhea, according to the CDC. So far, researchers have pinpointed a couple of strains that have been shown to reduce the severity and duration of traveller's diarrhea: Saccharomyces boulardii CNCM I-745 and L. rhamnosus GG.
While it's a promising theory, the bad news is most experts agree that much more research needs to be done on the topic before doctors can start recommending any type of probiotic as a treatment or preventive method for traveller's diarrhea. Also: the strains they've pinpointed so far are hard to find in a consumer-friendly form, and since supplements are not regulated by the Food and Drug Administration it's hard to know what exactly is in over-the-counter probiotic supplements, generally. "I think we will eventually get there in the future, but right now we are still learning how the systems of colonization resistance [work], and how we can modify things in the human [body]," Dr. Riddle says.
At the end of the day, traveller's diarrhea is a foodborne illness; in fact, it's most often caused by ingesting E.coli, the same type of bacteria that is often behind food recalls and food poisoning here at home. That means the best way to prevent traveller's diarrhea is just to take care to be vigilant about common-sense food safety practices while you're travelling. Skip raw delicacies, and eat thoroughly cooked, hot foods instead. Avoid raw fruits and vegetables (unless you've washed them with clean water or removed the skin). Drink bottled water only, and opt out of ice made from tap water, especially in developing countries where water safety is trickier. And don't forget to wash your hands with soap and water after using the bathroom and before eating. Hand sanitizer alone might not kill these diarrhea-inducing germs.
If you're really worried about it (maybe you've had it really bad before or your destination is particularly risky), best advice is to talk to your doctor before you go. This way, you can pack antibiotics to have on hand just in case. Also pack an OTC antidiarrheal (such as Imodium A-D), Dr. Riddle says. "Mild diarrhea (illness that does not affect your ability to carry out daily activities of travel) does not need antibiotics." If symptoms get worse, you'll have a dose of antibiotics ready to go.
If you want to add probiotics to this list of tactics, go for it. In all likelihood they won't help prevent or treat your diarrhea if it strikes, but they could help keep you regular, which is often a challenge when you're vacationing, too. Or, if you get diarrhea as a side effect of the antibiotics (yep, sometimes antibiotics backfire!), probiotics may shorten the duration, Dr. Riddle says. "Though stopping the medication usually also helps to stop the symptoms," he says.
And if you do everything right, and Montezuma's revenge still comes for you? Don't worry. Most cases will pass on their own, but if your diarrhea turns bloody, comes with a fever, or lasts for more than a few days, you should go see a doctor.