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Problems With Gut Microbiome Tests Available to Consumers

Oral microbiome Credit: Wikipedia

People have questions about the direct to consumer (DTC) gut microbiome tests that are now available from at least 31 companies. What do the results mean and can we believe them?  Well... according to a recent article in the medical site Medscape, the tests may be appealing to the consumer, but right now they don't mean anything at all.

This is because the tests are both unreliable and unregulated. Results of microbes found in the stool will vary from day to day, and from test to test. The same stool samples sent to different companies or even to the same company come back with different results. Generally the tests are offered by companies that want to sell you something - their supplements or other products in order to "improve your gut health."

However, there is no evidence backing up their claims. The tests are also not consistent - some do genetic sequencing, but others are just culture or a microscopic analysis (which find only a few of the microbes in the microbiome). Researchers stress that standardization of these tests is needed.

Yes, the gut microbiome has a tremendous effect on health and disease, and microbiome therapies definitely have potential. But right now it's buyer beware!

Excerpts from Medscape: Are Direct-to-Consumer Microbiome Tests Clinically Useful?

Companies selling gut microbiome tests directly to consumers offer up a variety of claims to promote their products.

"We analyze the trillions of microbes in your gut microflora and craft a unique formula for your unique gut needs," one says. "Get actionable dietary, supplement, and lifestyle recommendations from our microbiome experts based on your results, tailored to mom and baby's biomarkers.…Any family member like dads or siblings are welcome too," says another.

The companies assert that they can improve gut health by offering individuals personalized treatments based on their gut microbiome test results. The trouble is, no provider, company, or technology can reliably do that yet.

The microbiome is the " constellation of microorganisms that call the human body home," including many strains of bacteria, fungi, and viruses. That constellation comprises some 39 trillion cells.

Although knowledge is increasing on the oral, cutaneous, and vaginal microbiomes, the gut microbiome is arguably the most studied. However, while research is increasingly demonstrating that the gut microbiome has clinical implications, much work needs to be done before reliable applications based on that research are available.

But lack of scientific evidence and validity hasn't stopped a growing number of companies across the globe from offering direct-to-consumer (DTC) microbiome tests, Erik C. von Rosenvinge, MD, a professor at the University of Maryland School of Medicine and chief of gastroenterology at the VA Maryland Health Care System, Baltimore, told Medscape Medical News.

"If you go to their websites, even if it's not stated overtly, these companies at least give the impression that they're providing actionable, useful information," he said. "The sites recommend microbiome testing, and often supplements, probiotics, or other products that they sell. And consumers are told they need to be tested again once they start taking any of these products to see if they're receiving any benefit."

von Rosenvinge and colleagues authored a recent article in Science arguing that DTC microbiome tests "lack analytical and clinical validity" — and yet regulation of the industry has been "generally ignored." They identified 31 companies globally, 17 of which are based in the United States, claiming to have products and/or services aimed at changing the intestinal microbiome.

Unreliable, Unregulated

The lack of reliability has been shown by experts who have tested the tests.

"People have taken the same stool sample, sent it to multiple companies, and gotten different results back," von Rosenvinge said. "People also have taken a stool sample and sent it to the same company under two different names and received two different results. If the test is unreliable at its foundational level, it's hard to use it in any clinical way."

Whether test results from commercial companies are positioned as wellness aids or diagnostic tools, providing advice based on the results "is where the danger can really come in," Kao said. "There is still so much we don't know about which microbial signatures are associated with each condition."

What to Tell Patients

"Doctors should be advising against this testing for their patients," gastroenterologist Colleen R. Kelly, MD, Brigham and Women's Hospital, Boston, told Medscape Medical News. "I explain to patients that these tests are not validated and are clinically meaningless data and not worth the money. There is a reason they are not covered by insurance."

von Rosenvinge said that the message to patients "is that the science isn't there yet to support using the results of these tests in a meaningful way. We believe the microbiome is very important in health and disease, but the tests themselves in their current state are not as reliable and reproducible as we would like."

Kelly said she worries that "there are snake oil salesmen and cons out there who will gladly take your money. These may be smart people, capable of doing very high-level testing, and even producing very detailed and accurate results, but that doesn't mean we know what to do with them."

She hopes to see a microbiome-based diagnostic test in the future, particularly if the ability to therapeutically manipulate the gut microbiome in various diseases becomes a reality.

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