Lots of things can disrupt your gut health over the years. A high-sugar diet, stress, antibiotics – all are linked to bad changes in the gut microbiome, the microbes that live in your intestinal tract. And this can raise the risk of diseases.
It could be possible, scientists say, by having people take a sample of their own stool when they are young to be put back into their colons when they are older.
While the science to back this up isn’t quite there yet, some researchers are saying we shouldn’t wait. They are calling on existing stool banks to let people start banking their stool now, so it’s there for them to use if the science becomes available.
But how would that work?
First, you’d go to a stool bank and provide a fresh sample of your poop, which would be screened for diseases, washed, processed, and deposited into a long-term storage facility.
Then, down the road, if you get a condition such as inflammatory bowel disease, heart disease, or type 2 diabetes – or if you have a procedure that wipes out your microbiome, like a course of antibiotics or chemotherapy – doctors could use your preserved stool to “re-colonize” your gut, restoring it to its earlier, healthier state, said Scott Weiss, MD, professor of medicine at Harvard Medical School, Boston, and a coauthor of a recent paper on the topic. They would do that using fecal microbiota transplantation, or FMT.
Timing is everything. You’d want a sample from when you’re healthy – say, between the ages of 18 and 35, or before a chronic condition is likely, said Dr. Weiss. But if you’re still healthy into your late 30s, 40s, or even 50s, providing a sample then could still benefit you later in life.
If we could pull off a banking system like this, it could have the potential to treat autoimmune disease, inflammatory bowel disease, diabetes, obesity, and heart disease – or even reverse the effects of aging. How can we make this happen?
Stool banks of today
While stool banks do exist today, the samples inside are destined not for the original donors but rather for sick patients hoping to treat an illness. Using FMT, doctors transfer the fecal material to the patient’s colon, restoring helpful gut microbiota.
Some research shows FMT may help treat inflammatory bowel diseases, such as Crohn’s or ulcerative colitis. Animal studies suggest it could help treat obesity, lengthen lifespan, and reverse some effects of aging, such as age-related decline in brain function. Other clinical trials are looking into its potential as a cancer treatment, said Dr. Weiss.
But outside the lab, FMT is mainly used for one purpose: to treat Clostridioides difficile infection. It works even better than antibiotics, research shows.
But first you need to find a healthy donor, and that’s harder than you might think.
Finding healthy stool samples
Banking our bodily substances is nothing new. Blood banks, for example, are common throughout the United States, and cord blood banking – preserving blood from a baby’s umbilical cord to aid possible future medical needs of the child – is becoming more popular. Sperm donors are highly sought after, and doctors regularly transplant kidneys and bone marrow to patients in need.
So why are we so particular about poop?
Part of the reason may be because feces (like blood, for that matter) can harbor disease – which is why it’s so important to find healthy stool donors. Problem is, this can be surprisingly hard to do.
To donate fecal matter, people must go through a rigorous screening process, said Majdi Osman, MD, chief medical officer for OpenBiome, a nonprofit microbiome research organization.
Until recently, OpenBiome operated a stool donation program, though it has since shifted its focus to research. Potential donors were screened for diseases and mental health conditions, pathogens, and antibiotic resistance. The pass rate was less than 3%.
“We take a very cautious approach because the association between diseases and the microbiome is still being understood,” Dr. Osman said.
FMT also carries risks – though so far, they seem mild. Side effects include mild diarrhea, nausea, belly pain, and fatigue. (The reason? Even the healthiest donor stool may not mix perfectly with your own.)
That’s where the idea of using your own stool comes in, said Yang-Yu Liu, PhD, a Harvard researcher who studies the microbiome and the lead author of the paper mentioned above. It’s not just more appealing but may also be a better “match” for your body.
Should you bank your stool?
While the researchers say we have reason to be optimistic about the future, it’s important to remember that many challenges remain. FMT is early in development, and there’s a lot about the microbiome we still don’t know.
There’s no guarantee, for example, that restoring a person’s microbiome to its formerly disease-free state will keep diseases at bay forever, said Dr. Weiss. If your genes raise your odds of having Crohn’s, for instance, it’s possible the disease could come back.
We also don’t know how long stool samples can be preserved, said Dr. Liu. Stool banks currently store fecal matter for 1 or 2 years, not decades. To protect the proteins and DNA structures for that long, samples would likely need to be stashed at the liquid nitrogen storage temperature of –196° C. (Currently, samples are stored at about –80° C.) Even then, testing would be needed to confirm if the fragile microorganisms in the stool can survive.
This raises another question: Who’s going to regulate all this?
The FDA regulates the use of FMT as a drug for the treatment of C. diff, but as Dr. Liu pointed out, many gastroenterologists consider the gut microbiota an organ. In that case, human fecal matter could be regulated the same way blood, bone, or even egg cells are.
Cord blood banking may be a helpful model, Dr. Liu said.
“We don’t have to start from scratch.”
Then there’s the question of cost. Cord blood banks could be a point of reference for that too, the researchers say. They charge about $1,500 to $2,820 for the first collection and processing, plus a yearly storage fee of $185 to $370.
Despite the unknowns, one thing is for sure: The interest in fecal banking is real – and growing. At least one microbiome firm, Cordlife Group Limited, based in Singapore, announced that it has started to allow people to bank their stool for future use.
“More people should talk about it and think about it,” said Dr. Liu.
A version of this article first appeared on WebMD.com.