I have a piece in the NYT Sunday Review exploring the question: Should we bank our own stool for microbial reconstitution?
A few notes and interesting tidbits that didn’t make it into the piece.
First, an interesting study linking early-life microbial disturbances with the later development of asthma was just published in Science Translational Medicine. Unlike other studies, which look backward in time to make these associations, and which are therefore weaker, this one was prospective. It followed the kids over time. And the scientists identified four types of bacteria that seemed to be depleted in children who later developed asthma.
How to show causality? They put those bacteria in asthma-prone mice and, lo and behold, those mice were less likely to wheeze.
Notably, one factor identified in the loss of these bacteria was antibiotics use early in life. It’s a nice study, one that raises a question left unaddressed in my piece, but which I’ll raise here: Instead of restoring all your microbes—i.e. instead of eating your own feces— what about “rationally designed” probiotics that replace just these microbes critical to inhibiting the development of asthma and whatever else? And what about giving these probiotics routinely during or after antimicrobial therapy?
ON THE COST OF STOOL BANKING
As I reported the piece, I began to imagine a future in which huge, refrigerated warehouses stored frozen poo for each citizen. Just in case.
But Kevin Katz, who headed the pilot program on proactive stool banking at North York General Hospital in Toronto, burst that bubble. He pointed out that the cost per life saved would be prohibitive if stool banking were rolled out for everyone.
The question is, what about if proactive stool banking prevented chronic diseases, not just infection? Would the numbers change — would it become cost-effective? Remember 20 percent of Americans have hay fever; around 8 percent have asthma, not to mention the other chronic diseases linked with antibiotics. These are all quite costly.
Would the numbers be more favorable IF we knew that fecal reconstitution could prevent some percentage, however small, of these disease?
Eric Pamer of Memorial Sloan Kettering made another interesting point. In the context in which he works (leukemia patients developing terrible antibiotic-resistant infections), by preventing those infections, he’s not only potentially saving these patients’ lives; he’s also saving money spent on isolation wards — the patients are kept away from everyone else — and expensive cleaning procedures. Furthermore, he’s preventing other people from getting infected. Because leukemia patients who develop these infections become incubators for terrible pathogens, shedding and spreading the organisms about. In his view, preventing these sequelae unquestionably make proactive stool banking cost-effective.
Again, it’s interesting to contemplate how this might also apply to the general population. Cost effectiveness depends on what fecal restoration really prevents, which we don’t know yet.
ON TECHNICAL DIFFICULTIES — I.E. HOW IT WOULD ACTUALLY WORK
The microbiota continues to change and evolve throughout life, responding to dietary shifts, illness, age, exposures, your new dog, etc. And experts raised interesting points on how this complicates proactive stool banking. For example, should you “deposit” into your bank every year? Twice a year? More often, or less? Would a sample from 10 years ago be dangerous to you — since in 10 years, a lot can change? Should you try to get your microbiome “in shape” before you deposit, by, for example, eating a healthy, junkfood-excluding, high-fiber diet for a month or so before banking your stool? All these questions remain unanswered.
It’s also worth noting that fecal transplant for C diff began, as a procedure, using fresh stool. Now banking organizations, such as OpenBiome, prepared and freeze the feces so that it’s store-able. But as Brett Finlay — senior author on the asthma study mentioned above — pointed out to me, not all bugs freeze equally well. What if those key disease-preventive microbes don’t survive the freezing?
Finally, I asked people about DIY — which I absolutely don’t recommend. But I asked. And truth is, somewhat surprisingly, scientists didn’t dismiss the possibility . You need some expertise to do the blending and freezing right, of course. And getting it in a pill, if that’s the preferred delivery method — well, imagine getting poo into a tiny capsule in your kitchen. Yet everyone I asked made this point: The storage freezer needs to stay frozen — meaning, that, at a minimum, it can’t be a frost-free freezer. Temps often fall in those, apparently. And you don’t want a repeatedly thawed and refrozen sample.
Finally, here’s an unanswered question that needs answering: Let’s say the science proves autologous transplants work–that it has great preventive potential. How will you deliver to a young kid who can’t swallow pills? Invasive procedures (e.g. nasogastric tube, or enema) come to mind. But it seems like too much. This is a major stumbling block.