“What is good gut health?” is a question that makes Alexander Khoruts, MD, a M Physicians gastroenterologist, chuckle. “There is no consensus on what good gut health is, in terms of definition.” 

A member of the American Gastroenterological Association’s advisory board on the gut microbiome, Dr. Khoruts says that experts are just starting the conversation about how to best define and measure gut health. These measures include symptoms, lab tests of inflammation and which gut microbes play roles in our health. “So maybe in 20 years, we’ll have a definition.”

That’s because the exploration of gut health is a relatively young field, Dr. Khoruts says. It’s a field where there is still quite a bit of ambiguity, which is what Dr. Khoruts has spent his career making more concrete, both in his research and in treating patients. 

Doctors and researchers are not alone in navigating the murkiness that is gut health – many patients feel it too. 

The gut, the brain and the symptoms

“There are many gut diseases, like ulcerative colitis, Crohn’s Disease and others that we can examine and diagnose pretty readily,” Dr. Khoruts explains, “But in the majority of our patients, the gut appears structurally normal, but they are experiencing symptoms like cramps, diarrhea, chest pain, irregular bowel movements, fecal urgency or nausea.” 

Much of what we feel in our gut comes down to gut-brain interactions, Dr. Khoruts explains, where there can often be miscommunication. “This happens because the gut can’t send a detailed message to the brain about what is making it unhappy.”

Instead, the brain has to interpret many messages that come from the gut, and these often manifest as painful cramps or nausea, Dr. Khoruts says.

He also notes that “people who live with anxiety, too, can get caught in a loop. When people are stressed, they become more sensitive to the messages from the gut. Anxiety can lead to hypervigilance about symptoms, which then cause more anxiety, and the symptoms only get worse.”

“The painful symptoms and uncertainty about their cause are frustrating for patients,” Dr. Khoruts notes, many of whom may turn to probiotics to help with their gut and symptoms.

What’s the deal with probiotics?

“There is a scientific definition of probiotics,” Dr. Khoruts explains, “Which is that they are live microorganisms that, when given in appropriate or sufficient amounts, will benefit health. But that’s not a legal definition.”

According to Dr. Khoruts, the U.S. Food and Drug Administration (FDA), the agency that oversees the nation’s medicines, has a legal definition for a medicine or drug, “which is anything that treats, mitigates or prevents disease.” 

In theory, Dr. Khoruts says probiotics that come in the form of manufactured tablets or capsules can be a drug, but none have been proven to meet the FDA’s definition. “And so, instead of being regulated like drugs, where products have to be proven to be safe and effective for a disease, probiotics land in the health and wellness industry, where the claims are very, very vague.” 

While the FDA has determined that many of these probiotic capsules are likely not harmful, Dr. Khoruts cautions that they have not been scientifically proven to help with gut health or symptoms, and that the majority of these probiotics are not even what their labels say they are. 

“90% of the time, what’s on the label isn’t actually what’s in the bottle,” Dr. Khoruts says. “These microbes may be dead, they may be the wrong microbes altogether or they could be in the wrong amounts.”

A common reason healthcare providers may recommend probiotics is to facilitate recovery of microbes in the gut after exposure to antibiotics. In fact, there have been limited studies to test this idea. But, Dr. Khoruts explains, the exact opposite happened. “These probiotics actually delayed recovery of gut microbes.” 

“The marketing tactics are very clever,” he says, noting, “Probiotics are promoted with vague, but enticing claims like ‘this improves digestive health.’” 

In reality, according to Dr. Khoruts, since scientists are still defining what digestive health looks like, regulatory agencies like the FDA cannot deny that kind of claim. 

“The companies certainly don’t tell you that their products treat irritable bowel syndrome or any other specific disease because this would invite the scrutiny of regulators like the FDA,” he says, “As a result, people end up wasting a lot of their hard-earned money.” 

Wait, what about kombucha, yogurt or kefir milk?

It’s important to note that these marketed probiotics are different from foods or drinks with probiotic properties, like kombucha, kefir milk and yogurt, which Dr. Khoruts prefers to label as “fermented foods.” 

Fermentation is an ancient way of preserving the nutritional value of food without modern industrial processing or added chemicals. Beyond kombucha, kefir milk and yogurt, other popular fermented foods include sauerkraut and kimchi. 

“There was a highly publicized study last year that compared the composition of gut microbes that are believed to be beneficial in people who consume a lot of fermented foods versus those who didn’t,” Dr. Khoruts says. It showed that those who ate fermented foods have greater diversity in their gut microbes, which is associated with good health.

“It’s just one study, but it does help me clinically,” Dr. Khoruts says, also noting that “the results could be more due to the nutritional value of food instead of the content of microbes that do the fermenting, but it’s helpful, and more studies could look into that too.”

The bottom line about gut health

“This is still a young field.” Dr. Khoruts notes. While there is still much to discover and learn, what we do know helps: “Eating a plant-based diet with minimally processed foods, including fermented foods, continues to be good for people who are looking to keep their guts and overall health in shape.”

In terms of troubling symptoms patients may have, Dr. Khoruts recommends that they discuss their concerns with their doctor, who can refer them to a gastroenterology specialist, if needed. 

In the meantime, Dr. Khoruts and his colleagues are continuing to investigate the gut and learn more about how medicine can continue to help, unclouding the future and defining improved gut health for all.