‘Gut-Healing’ Probiotic Supplements Are Everywhere Right Now. Here’s What the Science Says | SELF

Oct 17, 2024

If you haven’t noticed, we’re living in the “heal your gut” era. Within the past few years, there’s been a wild influx of influencers, documentaries, cookbooks, and news articles breaking down how you can eat this or take that to “fix” your gut, and subsequently, a range of health problems. As someone who deals with horrible stomach issues, I have lurked in Reddit “microbiome” threads for tips and clicked on catchy ads for probiotic supplements that claim to get rid of uncomfortable bloating or cure chronic indigestion. And I’ll admit it: They intrigue me. I would love nothing more than to throw money at a pill or powder that makes it easier (and less painful) for me to digest food. But sadly, my gastroenterologist has told me multiple times (because I’ve asked multiple times) that probiotic supplements likely won’t fix my messed up tummy.

Linda Lee, MD, the chief of the division of gastroenterology at Northwell Health’s North Shore University Hospital in Manhasset, New York, tells SELF that, over the years, lots of her patients have asked about probiotics too. So much research is being published on the importance of the gut microbiome—the trillions of microorganisms, like bacteria, viruses, and fungi, that naturally reside in your GI tract—and how it both contributes to and protects against the development of chronic diseases like diabetes and cancer, disorders like irritable bowel syndrome (IBS), and mental health conditions like depression and anxiety. As scientists have learned more, there’s been a rapid push to figure out how these microbes can be strategically used to improve our well-being.

So naturally, “gut health” and “microbiome” swiftly became buzzwords in wellness spaces on and offline. “Companies have tapped into that interest—and maybe even fear—and convinced people that they need to take a probiotic supplement to correct what’s ‘wrong’ in there,” Dr. Lee says. There are gummies and powders and capsules that can, allegedly, do it all—and we gobble them up (spending billions on probiotic products every year in the process). But here’s the catch: Scientists don’t have a solid grasp on whether probiotic supplements have legit benefits or even how they might work—at least not yet. As Aparna Church, PhD, the codirector of the Goodman-Luskin Microbiome Center with UCLA Health, tells SELF: “It’s a hot mess.”

If you, like me, find yourself enchanted by the potential benefits of probiotic supplements, keep reading. We take a deep dive into what we do (and don’t) know about these encapsulated little critters—and when, if ever, it’s a good idea to take them.

Probiotics are bacteria and yeasts that, simply put, are presumed to have some kind of health benefit. These good bugs are naturally found in fermented foods, like yogurt, kombucha, kefir, sauerkraut, and kimchi, among others. And when they make their way into your GI tract, they can alter your microbiome and support things like digestion, brain health, and immune function. Different bugs are being studied for different effects: Bifidobacterium are thought to inhibit the growth of harmful pathogens and potentially fight cancer cells, for example, while Lactobacillus might reduce gut inflammation (a common precursor to chronic diseases) and ease digestive woes like diarrhea.

Dr. Church, who’s dedicated her career to studying the gut microbiome, believes probiotics—as in, the actual bugs in fermented foods—are (generally) great. They have so much potential that it’s no surprise companies decided to cash in and pack them into capsules and sell them as catch-all wonder-workers. But probiotic-rich foods and probiotic supplements are not one and the same. Fermented foods typically contain a wide variety of good bacteria that are “alive and active in natural environments,” says Dr. Church, whereas supplements usually contain a high concentration of specific strains that were freeze-dried and stuffed into a pill. “One’s more controlled, one’s more natural,” she says (more on why that matters below).

We are in the golden age of probiotics research. Growing evidence suggests certain types of good bacteria can ease GI symptoms like bloating, shorten the duration of some infections, support mental health, ease inflammatory skin issues like eczema, and improve metabolic conditions like diabetes. “We know that probiotics are good. We know that,” Dr. Church says.

However, there are only a few specific scenarios that probiotic supplementation is currently recommended for, like pouchitis, which is inflammation of an artificial “pouch” that’s surgically placed in the colon of certain folks with inflammatory bowel disease (IBD), like Crohn’s or ulcerative colitis. Probiotics are also often recommended for preterm infants to prevent certain complications that are caused, in part, by microbiome disturbances. And they’re occasionally used to restore gut bacteria in kids and adults taking antibiotics, as these meds can wipe out both good and bad germs, often leading to a bad case of diarrhea. But this route is hotly debated, even among experts and accredited organizations. So far, the potential benefit of taking probiotic supplements while on antibiotics has largely been seen in people with a higher risk of C. difficile infection, a harmful bacteria that can colonize the gut once the good guys are knocked out. (Even in this situation, there are varying criteria for “high-risk” among doctors.)

Experts can’t say for sure if these good bugs alleviate symptoms of or prevent digestive conditions like IBD or pancreatitis, and while some data show they might help improve immune-related issues like allergies and asthma, it’s too soon to start shelling out supplements to folks diagnosed with them. Even with IBS, probiotics are only recommended to those involved in a clinical trial (so things like safety can be controlled while side effects and efficacy are carefully monitored). It’s not that probiotic supplements are total BS—Dr. Church is hopeful that one day we’ll have the rigorous science needed to create expansive guidance, but we’re just not there yet. Case in point: If you look at the American Gastroenterology Association’s guidance on probiotics, you’ll see its recommendations (or lack thereof) are often chalked up to a “knowledge gap” or a varying “quality of evidence.”

As for the average, generally healthy person who grabs a bottle of probiotics tablets at Whole Foods? “There’s no evidence that taking a probiotic [supplement] is actually beneficial to you if it’s not for a specific condition,” Dr. Lee says.

Here’s where we’ve gotten ahead of ourselves: There isn’t one perfect gut microbiome everyone should strive for, says Dr. Lee. In fact, there are likely different kinds of bacterial communities that are good for human health. You probably have a mix of bacteria that’s different from the germs camping out in my intestines. Remember: This idea that you can take any ol’ probiotic to “fix” your gut health is an extremely appealing but faulty one. “We don’t even know if a probiotic you take is really ideal for you versus somebody else,” says Dr. Lee.

The major shortfall of probiotic supplements is they operate off the claims that these bugs can help treat, say, a vaginal infection or persistent bloating for basically anyone. Again, don’t get us wrong—some supportive evidence suggests they might ease certain symptoms. But what people often don’t realize, according to Dr. Lee, is that the strains examined in scientific trials are very specific; there are trillions of organisms that come in various strains, each of which can have vastly different health effects in people.

For example, when Dr. Lee’s IBS patients ask if they should be taking a probiotic, she’ll walk them through the existing research and explain how, for example, some studies discovered that Bifidobacterium helped people with IBS feel less bloated—but she’ll stress this doesn’t mean it’ll help them specifically, even if they have IBS, even if they take a pill loaded with Bifidobacterium. “Just because one strain [used in a study] was helpful for IBS does not mean another Bifidobacterium strain is going to confer the same benefits,” Dr. Lee says. To make matters more complicated, there are different types of IBS—certain folks largely deal with constipation, others diarrhea, and some get a combo of the two—that might influence how their bodies react to specific bugs. Your genetics, biological sex, diet, general health history, and even where you live might affect your response to certain probiotics too. As a result, “what might work for one person might not work for another,” says Dr. Church.

Supplements, shampoos, and serums that offer impressive results are everywhere right now. Experts have thoughts.

The body of growing research, at large, is also all over the place. “Different studies often use different strains of probiotics at varying dosages, making it really hard to compare the results and draw definitive conclusions,” says Dr. Church. There’s no standardization across the board. Plus, a lot of studies often use a small, mostly white group of people, lack a placebo (which ensures any reported effects are legitimate), and only look at the short-term risks and benefits. For context, studies should include a lot of people (not just rats!) who come from different backgrounds and are studied over a lengthy period of time—at least a few months, ideally longer. Without these factors in place, the findings aren’t reliable, says Dr. Church.

Companies want to get their supplements out on the market fast because probiotics are hot right now—but they can’t do that if they take the time to conduct a high-quality yearslong trial. Dr. Church says that we desperately need long-term safety and efficacy data before we can come to a consensus, before we can say any particular probiotic works for a certain health issue and why. The only consensus, it seems, is that the jury is still out.

To make matters stickier, supplements aren’t regulated by the FDA. Unlike pharmaceutical medications, probiotic pills and capsules aren’t required to undergo rigorous safety and efficacy testing (hence the whole research dilemma detailed above). They can, pretty much, be created and thrown onto shelves—the FDA will only go after a brand if, after the fact, the supplement seems to be causing health issues for people who’ve taken it. It’s illegal for a manufacturer to claim its supplement can treat or cure diseases, but they can say something nebulous like “This pill supports your gut health.” So they do.

The lack of federal regulation also means there’s no telling what’s actually in your probiotic pill. Studies have found that the ingredients included in these capsules don’t always match what’s listed on their packaging. Some contain significantly lower levels of the bacteria they claim to have, completely different types of microbes than the label specifies, and, in some cases, pathogens that can potentially make you sick. (This is particularly concerning for people who are immunocompromised. Probiotic supplements, in general, aren’t recommended for folks with weakened immune systems because they can increase the risk of an infection.)

There’s also the looming question of whether the bugs can even survive the journey from the manufacturing plant, into the capsule, onto the (likely hot) truck, into the store, from your car to your house, into your acidic stomach, and finally, through the rest of your gut. These factors can absolutely reduce the potential benefits of probiotics, says Dr. Church, so supplements need to be formulated and stored in a way that’ll keep them alive and viable before the bugs even brave the journey through your body. (This might look like freeze-drying and encapsulating them, which may wind up killing off bugs, or creating time-release formulas that are more resilient to heat—not like there’s any credible oversight on that!).

Before you add that “miracle” pill or powder to your cart, read this.

Even if you create and store them perfectly, the clock is working against you. “The number of live bacteria [in a supplement] decreases over time,” says Dr. Church. Right now, there’s no easy way for scientists to look inside a person’s intestines or measure fecal samples and determine if the probiotics survived all of the roadblocks, but in vitro experiments have shown viability plummets as they weather the harsh environment in your gut. Some manufacturers pack their pills with extra bacteria to try to account for this decline, but it’s not clear whether that’s an effective workaround.

Yet the biggest dilemma, at least in Dr. Church’s eyes, is misinformation. A lot of influencers share captivating stories about how probiotic supplements cleared their acne, eased their allergies, or kept their vagina clear of persistent infections—sometimes, they have megabucks deals with brands and reach millions of eyeballs. Much of what you see about any type of supplement on social media is inaccurate—but that doesn’t stop it from having an enormous influence over what people put into their bodies.

According to Dr. Lee, eating a diet rich in diverse and nutritious foods is the best way to support your gut microbiome. She gives this same advice to her patients, friends, and family: “If you really care about your gut health, pay attention to what you eat.” Every time you swallow a snack or meal, it tinkers with your gut bacteria. So start with probiotic-rich foods and toss some cheese into your salad, or reach for some Greek yogurt when you’re hankering for a snack.

Research has also shown that people’s gut bacteria expanded dramatically when they shifted from an omnivorous diet to a vegetarian one, and that a high-fiber diet (roughly 25 to 35 grams a day) can feed beneficial gut bacteria. (Good bugs feed off prebiotics, or special plant fibers, to grow, thrive, and survive.) Dr. Lee likens noshing on fiber to growing a garden: “You’re trying to cultivate good plants so you give it good soil and nutrients.”

If you want to try a probiotic supplement, clue in your doctor or a registered dietitian. They can walk you through the possible risks and benefits based on your individual health. Probiotic supplements are pretty low-risk if you’re generally healthy, so they likely won’t lead to any major side effects or issues (aside from less money in your bank account), says Dr. Lee. If anything, you might get gassy or bloated, in which case you can just stop taking them. The most important thing, according to Dr. Lee, is to temper your expectations since the most likely scenario is that they’ll do a whole lot of nothing.

When Dr. Lee sees people who really want to give probiotic supplements a shot, she suggests only taking them for a month. “If you’re feeling no better after a month, it’s probably not doing anything for you,” she tells them. And hey, maybe they seem like they do something for you (or you end up riding the high of a powerful placebo effect). If you feel like it’s making you burp less or reducing your acid reflux, it might be worth sticking with them if your doctor agrees it’s the best option for you. The reason: Studies have shown that once you stop taking a probiotic supplement, that bacteria disappears from your microbiome. “It’s not like you’re recolonizing yourself permanently by taking a probiotic for a shorter period of time,” Dr. Lee says.

This is not a shot at probiotics as a whole. Even the scientists who question the whole gut health movement think probiotics—and the promise they might hold—are pretty wonderful. It’s just easy to get swayed by flashy advertising and the buzz around these good bugs when they’re neatly packaged into a pill. Until we have the science to back supplements specifically, it’s crucial to recognize that no one knows if that pack of probiotic chews is doing anything for your gut or if it’ll only give you a quick case of the toots.

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