As awful as it sounds, scientists say taking a sample of your stool when you’re young to replace into your colon when you’re older could restore your gut to full health, and are calling for existing stool banks to encourage people to start banking their faeces now.
Lots of things can disrupt your gut health over the years. A high-sugar diet, stress and antibiotics are all linked to bad changes in the gut microbiome, the microbes living in your intestinal tract. And this can raise the risk for diseases.
But you might be able to erase all that damage, restoring your gut to a time when you were younger and healthier, say the scientists.
While the science to back up the storing of faeces in stool banks for future use is not conclusive yet, some researchers say we shouldn’t wait. They want existing stool banks to allow people to start banking their stool now, so it’s there for them to use if the science becomes available, reports Medscape.
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-colonise” your gut, restoring it to its earlier, healthier state, says Dr Scott Weiss, a professor of medicine at Harvard Medical School and a co-author of a recent paper on the topic. They would do that using a medical procedure called faecal microbiota transplantation, or FMT.
Timing is everything. You’d need a sample from when you're healthy, say, between the ages of 18 and 35, or before a chronic condition is likely, says 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 ageing, he says.
How can we make this happen?
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 faecal 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 ageing, such as age-related decline in brain function. Other clinical trials are looking into its potential as a cancer treatment, says Weiss.
But outside the lab, FMT is mainly used for one purpose: to treat Clostridioides difficile (C. diff), an infection caused by an overgrowth of C. diff bacteria. 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
There’s a certain ickiness to the idea of FMT, but banking our bodily substances is nothing new. Blood banks, for example, are common, 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 faeces (like blood, for that matter) can harbour disease, which is why it’s so important to find healthy stool donors. Problem is, this can be surprisingly hard to do.
To donate faecal matter, people must go through a rigorous screening process, says Dr Majdi Osman, chief medical officer for OpenBiome, a non-profit microbiome research organisation.
Until recently, OpenBiome operated a stool donation programme, 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,” Osman says.
FMT also carries risks, though so far, they seem mild. Side effects include mild diarrhoea, 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, says 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, says 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, says Liu. Stool banks currently store faecal matter for one or two years, not decades. To protect the proteins and DNA structures for that long, samples would probably 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 could survive.
This raises another question: Who’s going to regulate all of this?
The FDA regulates the use of FMT as a drug for the treatment of C. diff, but as Liu points out, many gastroenterologists consider the gut microbiota an organ. In that case, human faecal matter could be regulated the same way blood, bone, or even egg cells are. Cord blood banking may be a helpful model, Liu says. “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 faecal 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,” says Liu.
Study details
Rejuvenating the human gut microbiome
Shanlin Ke, Scott T. Weiss, Yang-Yu Liu
Published in Trends in Molecular Medicine on 1 August 2022
Highlights
• Industrial advances have been associated with large-scale changes in the human gut microbiome and a higher incidence of complex human diseases.
• Rewilding the human gut microbiome by transplanting the whole gut microbial community from donors in nonindustrial societies may result in a dramatic mismatch between our industrial environment/lifestyles and the ancestral microbiome.
• Emerging studies suggest that stool banking and autologous faecal microbiota transplantation (FMT), using the recipients’ own stool samples collected at a younger age when they are disease-free, may be a better – or at least an alternative – solution. This leads to the idea of rejuvenating the human gut microbiome.
• The conceptual similarity between stool banking for autologous FMT and cord blood banking for an autologous transplant implies the potential for rejuvenating the human gut microbiome.
Industrial advances have caused significant loss of diversity in our gut microbiome, potentially increasing our susceptibility to many diseases. Recently, rewilding the human gut microbiome – that is, bringing it back to an ancestral or preindustrial state (e.g., by transplanting stool material from donors in nonindustrial societies) – has been hotly debated from medical, ethical, and evolutionary perspectives. Here we propose an alternative solution: rejuvenating the human gut microbiome by stool banking and autologous faecal microbiota transplantation, that is, collecting the hosts’ stool samples at a younger age when they are at optimal health, and cryopreserving the samples in a stool bank for the hosts’ own future use. In this article we discuss the motivation, applications, feasibility, and challenges of this solution.
Medscape article – Your Poop May Hold the Secret to Long Life (Open access)
Trends in Molecular Biology article – Rejuvenating the human gut microbiome (Restricted access)
See more from MedicalBrief archives:
Super poo: The emerging science of stool transplants and designer gut bacteria
The war over faecal microbiota transplants
Faecal transplant produces sustained improvements in cognitive and clinical outcomes