Scientists say that healthy gut flora are teeming with a broad range of bacteria. A study in Nature Metabolism published in February 2021 looked at the gut flora of more than 9,000 people and found that healthy aging was associated with a diverse set of bacteria, while a lack of bacterial diversity was observable in a bunch of conditions, including unhealthy aging. The takeaway was that you want your digestive tract to be a rain forest of microbes, not a desert. That’s why grocery store shelves are lined with probiotic supplements claiming to have billions of microbes in each bottle that will boost microbiome diversity. The latest products catering to the interest in the type of bugs that live in your gut are at-home gut health tests. Ranging in price from $49 to nearly $350, these tests claim to inform you on ways to improve your intestinal ecosystem. Packages of tests and supplements can retail for up to $600. Are they worth it?
What Are These Tests and How Do You Take Them?
Some of the most popular tests out there are:
OmbreViomeThorneWellnicityFloréBiohmVerisana (also analyzes leaky gut, yeast infections, and Helicobacter pylori, which can cause an infection in your stomach)
Most tests follow a common protocol. You use a scooper or swab to get a small sample of stool. The sample is sealed in a vial and shipped back to the company. Several weeks later, the company will email you a personalized microbiome assessment: a report that lists the microorganisms residing in your gut and whether you’re at risk for certain diseases or disorders. Some tests will also send dietary and lifestyle recommendations. Ombre generates a personalized microbiome report, food recommendations, and a targeted probiotic, claiming their recommendations will boost mood, prevent weight gain, and improve digestion. In addition to personalized reports, some companies also sell their own probiotics, which they claim are customized to your microbiome to meet your needs, whether that’s boosting metabolism, improving cardiovascular health, increasing optimism, facilitating smoother digestion, or enhancing your immune system.
What Does the Science Say?
While the gut microbiome may be part of standard care at some point in the future, according to a review in Nature Reviews Gastroenterology and Hepatology from 2021, we’re not quite there yet. That’s why experts view these tests with deep skepticism. “Nobody should waste their money on these tests,” says Rabia De Latour, MD, a gastroenterologist and an assistant professor of medicine at NYU Langone Health in New York City. “The top researchers at the most innovative laboratories at the world’s best academic institutions with the highest levels of funding can’t do what these companies are claiming. We still cannot pinpoint which microbes are associated with which health outcomes.” Dr. De Latour added that a person’s gut microbiome is constantly changing, and one sample does not provide an accurate picture of a rapidly evolving ecosystem, which is why the tests are not a diagnostic tool, not covered by insurance, and not FDA approved. For tests like Verisana, De Latour points out that a doctor can perform an antigen test that is the gold standard for H. pylori, as well as prescribe medicines to eliminate an H. pylori infection. A study published in 2019 in Clinical Gastroenterology and Hepatology pointed out that the gut microbiome’s changeable nature makes it difficult to treat, and it’s a pitfall for doctors to assume it will remain stable. “We know that a change in diet can change the gut microbiome within 24 to 48 hours,” says Brian Lacy, MD, PhD, a gastroenterologist and a professor of medicine at the Mayo Clinic in Jacksonville, Florida. “And stress can change gut function and likely change the gut microbiome. It is a moving target for many patients. Thus, results of testing could change from week to week, if exercise, diet, stress, and medications all change.” Dr. Lacy noted other shortcomings of the tests. “It is estimated that we can accurately identify only 10 to 15 percent of all gut bacteria,” he says. “Even in a research setting, it is difficult to provide more than a broad overview of gut health and where there is a predominant species of one bacteria or another. The gut microbiome lives in a very delicate balance. At present, we cannot confidently state, in most cases, whether any individual has an issue with one strain of bacteria or another.” Both De Latour and Lacy say that good gut health depends on a balanced diet that is high in fiber, which feeds the beneficial gut bugs. They added that proper sleep, exercise, and stress reduction may also help improve gut health.
So, What Can the Tests Tell You?
Most of the tests claim to isolate the DNA of the bacteria and fungi found in your sample. They then figure out which gut bacteria have colonies in your intestines. Another caveat: The technology is limited and is able to identify only a fraction of the bacteria found in your stool sample. It is more than likely that most of your sample will be unidentified. The companies generally offer dietary suggestions and an opportunity to work with one of their nutritionists, as well as exercises and activities to improve gut health and a personalized vitamin and probiotic regimen the company sells. “Most probiotics have never been tested in scientific trials,” says Lacy. “Many are dead on arrival — meaning they are not live bacteria and may not work as well as publicized. Many do not even survive transit through the stomach and may not get to the colon where they are supposed to work.” Taking care of the microbes in the gut that take care of us is certainly a good idea, but experts caution that at-home gut-health tests won’t provide anything more insightful than advice to eat more vegetables, exercise, and reduce stress. “The bottom line: I do not recommend home gut-health tests,” says Lacy. “More importantly, there is no good data showing that you can act on the test results to change the gut microbiome.”
