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Fecal Transplants: Getting To The Bottom Of The Matter

Many Americans will be introducing more food than usual to their GI tracts on this Thanksgiving Day, and so I thought I’d provide you with a special gastroenterology-related post to complement the mood. If you have already eaten, I might suggest that you come back to this post on an empty stomach. I will be discussing the alternative medicine practice known as “fecal transplantation” and it is rather unsavory.

The idea of transferring stool from one person to another (for the treatment of various GI disorders) was first described in the 1950s. This month the TV show, Grey’s Anatomy, featured the practice in one of their plot lines – which rekindled interest in the therapy, and resulted in an explosion of search engine activity. I figured it was probably my duty, as a member of Science Based Medicine, to offer a rational analysis of the treatment in the hope that the Google gods will serve up my post to a few of the information-seekers out there. I hope to reach them before the snake oil salesmen, wrapped in their mantle of “gentle, natural cures,” convince them that they desperately need a good colon or liver cleanse, if not a fecal transplant.

Like most alternative therapies, fecal transplantation is based on a drop of truth and a gallon of pseudoscience. It is true that the gastrointestinal tract is teeming with hundreds of thousands of bacterial species and pseudo-species, and that without them we would die. It is also true that certain nasty bugs (like clostridium difficile) cause problems when they take up residence within the gut. Antibiotics do upset intestinal flora, much to the consternation of infectious disease specialists. Now, all that being said – the practice of repopulating the gut with another person’s stool requires some fairly grand assumptions about efficacy and safety that are not founded upon any clinical trial data whatsoever.

How It Works
My friend and pro-science advocate, Dr. Brian Fennerty, explained to me that the process of fecal transplantation (as described in the literature) requires a few steps. First, the undigested matter from the donor stool must be removed with some sort of straining device. Next the remaining fluid is spun in a centrifuge to reduce the material into a bacterial “pellet.” Finally the pellet may be introduced to the patient through a nasogastric tube, or reconstituted in liquid and inserted into the rectum in the form of an enema.

The Underlying Assumptions
In order to recommend fecal transplantation, one would have to make a number of assumptions. These giant leaps present little cause for hesitation among some alternative medicine practitioners:
• That gut derangements (such as inflammatory bowel disease) are caused by imbalances in intestinal flora
• That gut diseases could be improved or treated with introduction of donor stool to the GI tract
• That donor stool will provide the right sort of bacterial colonies to restore the correct “balance”
• That bacteria from donor stool will actually colonize the new gut, rather than exit with the next meal
• That a recolonization will endure long enough to affect the underlying disease being treated
• That donor stool will not introduce any unwanted pathogens
• That there are no negative side effects (sepsis, perforated colon, exacerbation of colitis, etc.) that outweigh the possible benefits.

The Dangers
The human GI tract is not just full of bacteria, but it can also be populated with viruses, fungi, protozoa and parasites. Fecal transplants can transmit HIV, prion disease, e. coli 0157:H7, worms, shigella and other dysentery-causing infectious agents. Current laboratory testing is unable to detect all possible pathogens, especially prions. It is therefore impossible to declare a stool sample “safe” with our current technology.

The Scientific Literature
To my knowledge, there have been no controlled trials to evaluate the outcomes of fecal transplants. There are several observational studies suggesting that patients with c. diff colitis and certain inflammatory bowel conditions improve after the introduction of donor feces. Of course, observational studies do not establish that the treatment is more efficacious than a tincture of time.

A summary of the literature (with references) may be found here. Ironically, the website that features these references claims that fecal transplants may be helpful in the treatment of everything from heartburn, to immune deficiencies, to autism.  Apparently, they didn’t analyze the literature they cite.

Conclusion
There is currently insufficient evidence to recommend fecal transplantation for any patient. There are clear risks, and no proven benefits.

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The Last Word
After reading this post my husband asked me, “How much do they pay donors?”

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