Potential Pitfalls
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,” Dr. Kao said. “There is still so much we don’t know about which microbial signatures are associated with each condition.”
“Even when we have a solution, like the Crohn’s exclusion diet, a physician doesn’t know enough of the nuances to give advice to a patient,” she said. “That really should be done under the guidance of an expert dietitian. And if a company is selling probiotics, I personally feel that’s not ethical. I’m pretty sure there’s always going to be some kind of conflict of interest.”
Supplements and probiotics are generally safe, but negative consequences can occur, Dr. von Rosenvinge noted.
“We occasionally see people who end up with liver problems as a result of certain supplements, and rarely, probiotics have been associated with infections from those organisms, usually in those with a compromised immune system,” he said.
Other risks include people taking supplements or probiotics when they actually have a medically treatable condition or delays in diagnosis of a potentially serious underlying condition, such as colon cancer, he said. Some patients may stop taking their traditional medication in favor of taking supplements or may experience a drug-supplement interaction if they take both.
What to Tell Patients
“Doctors should be advising against this testing for their patients,” gastroenterologist Colleen R. Kelly, MD, AGAF, Brigham and Women’s Hospital, Boston, said in an interview. “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.
Dr. Colleen R. Kelly
“Recommendations to purchase probiotics or supplements manufactured by the testing company to ‘restore a balanced or healthy microbiome’ clearly seem like a scam,” she added. “I believe some of these companies are capitalizing on patients who are desperate for answers to explain chronic symptoms, such as bloating in irritable bowel syndrome.”
Dr. 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.”
When patients come in with test results, the first question a clinician should ask is what led them to seek out this type of information in the first place, Dr. von Rosenvinge said.
“Our patient focus groups suggested that many have not gotten clear, satisfactory answers from traditional medicine,” he said. “We don’t have a single test that says, yes, you have irritable bowel syndrome, or no, you don’t. We might suggest things that are helpful for some people and are less helpful for others.”
Dr. 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.