In 2010, I read for the first time about Fecal Microbiota Transplants (FMT – though back then, they were just called Fecal Transplants); I quickly emailed my Science Partner in Crime, “Fecal transplants are going to be the weight loss strategy of the future. People are going to get shit enemas from Twiggy to be skinny.” His response: “Stop being gross. Stick to the science.”

In the five years since I started my research on the human as ecosystem, scientists are adding to our knowledge about human microbial make up and its importance to a myriad of human health issues at a seemingly exponential pace. In recent years, more and more mainstream publications like the LA Times, New York Times Magazine, National Geographic, among others, are synthesizing complex scientific papers and reporting this research about our miniscule inhabitants and human health. In addition, smaller more niche publications are jumping on the microbiome bandwagon, like parenting site Fatherly which supports “men who want to be great fathers without turning into clichés.” All this coverage allows the general public to become more and more educated on the necessity of maintaining a healthy ecosystem.

We are revising our relationship with germs. Probiotics are in. Rampant antimicrobial use is on its way out. We now understand that many people’s individual responses to certain foods, drugs, and diets have links to the types of microbes that live in their guts. We are starting to use antibiotics more judiciously and are looking for more precise ways of targeting disease-causing microbes that leave our beneficial ones intact. There are many great books on the market or forthcoming about the human microbiome, written by experts in their field like Martin Blaser (whose wife, Maria Domínguez-Bello, does interesting and important research on gut microbes (go women in science!!!)) and Rob Knight. All of these things are really, really good.

Reporting on a complex entity like the human ecosystem requires careful writing. It’s a rabbit hole with seemingly infinite side passages. Often in writing about the human ecosystem, we writers have to make a choice of which side passages we enter and which we ignore for the sake of clarity and brevity (of which this essay isn’t brief), always keeping in mind that we need to “do no harm” in the conclusions we offer to our readership who is trusting us to synthesize the information in a useful and accurate way. Happily, most of those who are reporting on advances in human microbiome research like Michael Pollan and Ed Yong are careful as well as damn good writers.

However, the tie-in of the microbial inhabitants in human ecosystem to human health is where things get tricky with writing. Readers often look to these articles for insight into how to affect positive changes in their own health, and the future of microbiome manipulation is so very bright with possibility. It is dissatisfying to read an essay about human health with the now clichéd take away of “eat right, exercise” (which despite its clichéd perception is still a very true and good take away). Often the temptation as a writer is to offer some sort of advice or juicy tidbit that can be construed as advice. No one, especially a suffering person, wants to be told “the science is complex, wait for more information.” Especially, as Michael Howard notes in “The Link Between Gut Bacteria and Your Kid’s Behavior Just Got Stronger,” when research on the human ecosystem moves at a “glacial pace.”

But this glacial pace and resulting frustration does not justify irresponsible journalism. And sadly, the last sentence of Howard’s essay—“In the meantime, root for the next-best thing: fecal transplants!”—falls into this category. Now, I don’t think Howard’s intention was to be irresponsible. Rather, I see this comment falling into my “Twiggy shit enema” category of “I can’t believe gross things like fecal transplants are real.” And I do appreciate that he did link to a Washington Post article that describes FMTs as treatment for chronic infection NOT child behavior. But will his readers, who come to Fatherly for parenting advice, be able to catch the nuance here? We can’t be certain of that. For all of its interest-piquing factor, FMT was a side tunnel in the rabbit hole that Howard should have either ignored for his essay or given more exploration than a seemingly flippant last sentence.

The BLUF (Bottom Line Up Front) of this essay is that FMTs are highly effective in changing human ecosystem, but at this time are not something a healthy (or even a fairly healthy) person should seek as an intervention. They are definitely not something a parent should give her child as a mood/behavior regulator.

“But if they are highly effective in changing human health, why can’t we explore them as treatment for behavior problems; certainly they must be more natural than pharmaceutical drugs?” You might ask.

The words “effective” and “change” (and even “natural”) are value neutral. FMTs work, but whether one will work in a way a recipient perceives as positive is not guaranteed (or even likely in most cases). The research we have on mood/behavior and the microbiome is still preliminary. How an FMT might affect this aspect of human health is still unclear. In fact, to my knowledge (and if someone knows otherwise, please forward the research to me, I could use it for my book), FMTs are not being considered in laboratory research for this kind of human treatment (there are some interesting mouse studies though). Where FMTs are being explored as treatment options is in chronic infection and obesity (see, I was right about Twiggy).

FMTs offer glorious possibility. As I’ve noted before:

Hospitals are often using fecal transplants to cure persistent C. difficile infections as well as other bowel dysfunctions. Now, studies in the Netherlands are investigating whether FMT can be a solution to metabolic syndrome and obesity to diabetes; while here, the Food and Drug Administration (FDA) is working out regulations to ensure the safety and efficacy of FMT as a routine treatment for persistent and highly pathogenic bacterial infections.

In all of these cases, the people undergoing FMT have experienced a disintegration of quality of life that the positives outweigh the possible negative outcomes of FMT.

You might ask now, “What are the negative outcomes? Besides an exchange of excrement, what exactly does an FMT do?”

Think about yourself as a walking world. On this world of you, there are many diverse environments: the desert of your back, the swamps of your genitals, the cave of your bellybutton, the jungle of your armpit. In each of these environments, live tiny organisms that have evolved to best survive in the ambient conditions. They process your sweat (sometimes into smelly byproducts), fight off intruders, and work with your human cells. The most intriguing (and most studied) human environment of all is the river valley of your gut. Here, even though they are technically outside of our bodies (the gut is essentially an external tube that runs through the center of all of us), gut microbes have a very personal relationship with the locals (our human cells); evidence shows that they “talk” directly to many of our organs including the brain and liver, affect our weight, immune function, and even mood. Microbes build fantastic structures on the mucus layer in the gut and pay rent by educating our immune system, providing food for our human cells in the form of short-chain fatty acids and essential vitamins, and fighting off any pathogenic microbe that might try to make a land grab—amongst many other things.

The colonization of your body-as-world begins at birth and continues throughout your lifetime. In fact, our uniqueness is not in our human cells but in the microbial (and I am including the viral) differences we have. As we age, the differences continue to mount even between identical twins (who do have a more closely related microbiota but a very different viral make up). From day one, our microbes are terraforming our gut (literally shaping its physical structure) and teaching our immune system what is safe and what is dangerous to our bodies. In fact, animal studies show that immune systems not exposed to microbes tend to be underdeveloped and a bit trigger happy (think allergies and autoimmune problems). Further, studies on birth mode (cesarean or vaginal) and infant feeding (formula or breast milk) are showing that these also affect the types of microbes that colonize us and subsequent gut and immune development.

FMT is an organ transplant. The FMT procedure weakens or kills off all of your microbial residents (but not necessarily your viral ones) so that they can then recolonize you with a whole new community of microbes. It’s the equivalent of taking the entire rainforest of South America and putting it in on another earth-like planet. You have moved one world to an entirely different one. And what about those native viruses who are still in the recipient’s gut? Well, over your lifetime, your particular viral make up has co-evolved with your particular microbes. With a whole bunch of new microbes (and their accompanying viruses), your resident viruses will no longer be in balance with the system. A viral war could break out. Or it might not. Your immune system might look at these new “good” microbes as friendly. Or they could freak out at all the new strangers and launch an autoimmune attack (similar to an organ transplant rejection). Or something else might happen when these new microbes start talking with your human system that we can’t anticipate. Right now, we can’t predict the outcome of an FMT in a particular individual.

Because we know that FMTs are so powerful and fraught with uncertainty, they are usually only medically approved as a last resort for people whose quality of life is severely diminished. Despite the simplicity of the technique (people do them at home), it is an extreme procedure. Donors have to be chosen very carefully. And even then, the outcome may be undesirable such as the case of the woman who reported unwanted weight gain after an FMT that cured her C. difficile infection. Further, the long-term effects are still unknown.

Research on the human ecosystem is as if all the scientists are working on a giant puzzle that depicts a color gradient: red on the top, violet at the bottom. But instead of each color being sharply delineated, they sloooooowly blend down the spectrum. So while red and violet pieces look very different, a reddish orange piece might be harder to properly place. One scientist may be holding a very important piece of the puzzle but may not know exactly where to put it in the big picture. So while we may know something like FMT is important, without knowing how it fits in the whole picture (or whole ecosystem), we can’t predict just how it will affect the puzzle construction (read: human health).

This is how research on the human ecosystem looks. We have intriguing sections of the puzzle filled out but still don’t quite understand the big picture yet. And until we understand the big picture, we need to proceed with caution. That caution extends to how we writers explain the puzzle pieces.

Yes, in the far future, I do believe that shit enemas will be routine for all sorts of human health issues—as I believe that designer probiotic mixes will be available for those Lego meltdowns (and other things) much sooner. However, in the meantime, we need to be careful with how we portray treatments and advances in scientific knowledge as well as how we implement them in ourselves and our children. Howard would have been better served to have ended his essay at the penultimate paragraph with the “clichéd” perspective Dr. Lisa Christian offered:

“It is possible that effects of diet would emerge if we used a more detailed assessment,” says Bailey’s co-author, Dr. Lisa Christian. “It is certainly possible that the types or quantities of food that children with different temperaments choose to eat affect their microbiome.”