Getting Your Microbiome Analyzed Probably Won’t Do Anything for Your Health

First of all, do you even know what a microbiome is?
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If you’re tuned into the ever-evolving, sometimes ridiculous world of wellness, you’ve likely heard about microbiome testing—the new-ish trend of testing the composition of your gut microbiome. Essentially, you mail in a fecal (yes, poop) sample to companies that will analyze your gut microbiome for a fee and send you results that tell you about the diversity of the bacteria in your gut. These results, they claim, can give you a better picture of your overall health and suggest what factors may be influencing it.

But is there any real science behind these claims? Is microbiome testing actually a helpful measure of your overall health? And will mailing off a poop sample really give you any actionable information about your health or diet? Before we get into any of that, let’s answer the basic question that most of you are probably asking yourself. 

What is a microbiome?

Your microbiome is a genetic snapshot of all the microscopic organisms in your body. Usually when people use the term, they’re referring specifically to the gut microbiome.

Increasingly, medical studies (and health food marketers) are referencing our “microbiota,” the collection of microbes—bacteria, viruses, yeast, and other microscopic organisms—that live in and on our body. While these microbes exist throughout our bodies, the gut microbiome is the most well-studied. And, though our entire microbiota includes several microscopic organisms, the best-studied microbes to date are bacteria, of which there are hundreds of species and trillions of individual cells.

Some of these bacteria can harm us, as potential pathogens—salmonella and E. coli are two well-known gut pathogens, for example—while others actively help us, producing vitamins or inhibiting the replication of pathogens; others are seemingly neutral, neither actively helping or harming, but thriving as a part of our internal microbial ecosystem.

When you send in your fecal sample for a microbiome test, it’s analyzed in a lab using a method called 16s RNA ribosomal sequencing. Basically, scientists isolate and sequence the DNA in your sample and look only at the part that comes from bacteria. This genetic snapshot of your microbiota is usually referred to as your microbiome. From the analysis, you learn what species of bacteria are present in your microbiome, and how diverse your microbiota is in comparison to others.

While the testing process is scientifically sound, it’s still unclear what conclusions can and can’t be drawn from the results. Despite ongoing research, we are in the early stages of understanding how our gut microbiome influences our health.

An abnormal microbiome is associated with certain health problems.

Studies have shown that abnormal (or dysbiotic) microbiomes can be associated with a number of diseases, including Crohn’s disease, cardiovascular disease, and even some cancers. “If someone has a chronic disease, for example, metabolic syndrome or inflammatory bowel disease, or is obese, you could almost guarantee that their microbiota composition would be abnormal,” Gail Hecht, M.D., professor of medicine and microbiology/immunology at Loyola University Stritch School of Medicine and chair of the American Gastroenterological Association Center for Microbiome Research and Education, tells SELF.

An abnormal microbiome may show significantly less diversity of bacteria than the typical microbiome, or may show overgrowth of certain bacteria that have been linked to health conditions. But it’s important to note that most studies examining links between disease and the gut microbiome have been association studies, where causation couldn’t be determined. In other words, it is unclear whether having an abnormal microbiome is a cause of disease, or if various disease conditions instead lead to an abnormal microbiome—we can’t be sure whether an abnormal microbiome is a cause of disease, or just a symptom.

So, while at-home microbiome tests can be helpful in flagging an abnormal microbiome, it’s difficult to draw any definitive conclusions from this information. Instead, anyone whose test shows abnormal results should consult a doctor for a professional diagnosis. If an abnormal microbiome is indicative of a health problem, a doctor can suggest appropriate forms of treatment.

Beyond that, scientists have yet to define what an optimally healthy microbiome looks like, if there’s even such a thing.

The microbiome is a spectrum and the line between healthy and unhealthy is blurry. A long-standing challenge of microbiome research has been to define what it means to have a “healthy” microbiome. Could there be some optimum combination of bacteria that ensures a person’s health? After years of research, it turns out there is really no such thing—at least, not just a single combination of organisms that qualifies as a healthy microbiome. Instead, a number of variations can all be considered healthy or normal.

Plus, your microbiome is constantly changing. “In one person, if you have your microbiome sequenced, even day to day there are going to be variations.” Dr. Hecht tells SELF. Changes in the microbiome can be due to what someone ate or drank that day, the presence of transient illnesses such as colds or diarrhea, or any medications—especially medications that target bacteria, such as antibiotics.

So, if you’re an otherwise healthy person, will knowing more about the bacteria present in your gut (your microbiome) really do anything for you? 

Likely not. If you’re already healthy, your microbiome composition will probably be much like other healthy individuals where you live, according to Dr. Hecht.

A number of studies have demonstrated that a diverse microbiome is associated with gut health, while one lacking diversity tends to be less healthy. However, knowing the exact number and types of species you carry in your gut isn’t really necessary.

Likewise, supplementing with probiotics might not do anything for otherwise healthy people.

As SELF previously reported, while studies on probiotics are promising, there’s little evidence to show that probiotic supplementation has a beneficial impact for healthy people. Plus, since supplements aren’t subject to the same regulatory standards as drugs, you may never really know what you’re getting. “The literature shows that in some [supplements], certain bacteria that are stated to be present on the label aren’t even there, so you have to be careful,” says Dr. Hecht.

The best, simplest way to promote gut health (which is what all the hype around the microbiome is really about) is to eat a healthy diet that includes plenty of fruits, vegetables, and other plant-based foods.

“What we eat has a major impact on the health of the gut microbiota,” says Dr. Hecht. That includes plenty of fiber, which may help feed your gut bacteria. “Nondigestible fiber comes from plants, including vegetables, fruits, grains, nuts, and legumes,” explains Dr. Hecht, who says that eating plenty of these foods will have a healthy impact on your microbiome.

If you want to include probiotics in your diet, Dr. Hecht suggests getting them from fermented foods—yogurt, kefir, kimchi, and kombucha are all food sources of probiotics—instead of supplements. But, realize that the probiotics in these foods are even more difficult to study than the probiotics in supplements, as the healthy bacteria content can vary so greatly. As such, there is not a good amount of scientific data to support their benefit in promoting a healthy microbiome.

Like many areas of health, there is no magic bullet or easy shortcut to a “healthy” microbiome, and chances are that if you’re otherwise healthy, your microbiome is as well.

Tara Smith, Ph.D., is an infectious disease epidemiologist and associate professor at the Kent State University College of Public Health.

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