Probiotic supplements contain healthy bacteria to support the microbiome, a collection of trillions of bacteria that live in our gut. “Think of probiotics as your little helpers that restore order and help maintain harmony in your gut ecosystem,” Vincent Pedre, M.D. told mindbodygreen. The microbiome is intricately connected with digestive health and the immune system. In fact 70 to 80 percent of the immune system lives in the gut1. Scientists believe that the immune system and the bacteria that live in the gut co-evolved2 to communicate and support one another. “Good” bacteria helps stimulate and prime the immune system to keep it in tiptop fighting shape against “bad” bacteria that can make us sick. In addition, some “good” bacteria produce toxins3 to fight off “bad” bacteria themselves. “They outnumber and antagonize unwelcome pathogens, including unfavorable bacteria, yeast, and parasites,” says Pedre. “Another way to think about it is the probiotics are like good cops,” Robert Rountree, M.D. told mbg. “We’re putting in the good cops, and the good cops can keep watch over the bad guys.” So a healthy gut equals a healthy and strong immune system. And that might comes in handy for staving off digestive issues, like one of the most common causes of diarrhea: travel-related exposure to pathogens. Millions of people each year contract diarrhea from unclean water and food or the general stress of travel. By maintaining a healthy gut, you can ensure your immune system is well-supported to fight back while you enjoy vacation. In fact, preemptively taking a probiotic might support healthy digestion, free of “traveler’s diarrhea"4 cases, according to a research review published in Travel Medicine And Infectious Disease. Popping a probiotic in times of gastrointestinal distress might also help manage the severity and duration of diarrhea. One research review even found that some probiotic strains were able to lessen the duration of diarrhea symptoms5 by a day. And when you’re tethered to the toilet, an extra day of relief is a huge win. Probiotic foods may be tough to stomach when your stomach is upset, especially dairy-based ones like yogurt, so you may want to stick to a supplement to reap the bacterial benefits. Glutamine is a nonessential amino acid, which means the body usually produces sufficient amounts, but in times of illness or extreme stress glutamine levels may become depleted7. This can weaken the intestinal walls and affect the body’s ability to properly and efficiently absorb nutrients during digestion. In addition, having low levels of glutamine may exacerbate or even cause diarrhea6. The enhanced speed of transit through the intestines can make it even more difficult to replenish glutamine and other important nutrients. Supplementing with glutamine when you have diarrhea can help repair the intestinal walls8 and support nutrient absorption. This is especially important for fighting dehydration, a common but potentially dangerous side effect of diarrhea. In fact, glutamine supplementation has been shown to significantly enhance water and electrolyte uptake6, lessening the severity of diarrhea and staving off dehydration. McDonough has developed & lead nutrition education programming in schools. She’s covered a wide range of topics as a health & nutrition reporter from the rise in the use of psychedelics for depression to the frustrating trend in shorter doctors’ appointments and the connection between diet and disease.