We are not one organism, we are many organisms. And when we disturb the relationship with our symbiotic partners, we can suffer unpleasant and sometimes life-threatening consequences. One of the most fascinating areas of medical research is the study of how our bodies interact with the the various organisms that we carry around, on us and in us. A focus is the gastrointestinal tract, particularly how the composition and function of those organisms contribute to what we think of as “normal” function, and how they can affect our risk for obesity and disease. My favorite analogy is from SBM’s own Mark Crislip who likened it to a “metaphorical rainforest” giving a vivid mental image of the of the number of species (thousands) in our guts, and the complexity of that ecology. If the gastrointestinal tract is a rainforest, then antibiotics are the metaphorical clear cutters, wiping out some of the normal bacteria, and creating the conditions where unwanted bacteria can grow.
Antibiotics are among the most useful (if not the most useful) classes of drugs in widespread use today. They’re also among the most widely prescribed, and both antibiotic overuse and their addition to animal feed present real dangers to their ongoing effectiveness. Their popularity stems in part from their effectiveness, but also from the perception that they are safe. And, in general, a course of most antibiotics is usually well tolerated. Among the side effects, diarrhea is common (with an incidence of 5% to 39%). It’s due in part to the antibiotic killing off our normal “good” bacteria, which can significantly change the most prevalent species. In some cases, “bad” bacteria can surge as a result. Clostridium difficile infection is pretty much the worst gastrointestinal consequence of antibiotic therapy. It isn’t just a cause of antibiotic-induced diarrhea, “C. diff” infections are virulent and vicious, spreading easily, especially among hospitalized patients, causing widespread misery and even killing. (more…)
I suppose it was bound to happen, but it still rankles. Here is the back cover of last week’s issue of the decreasingly prestigious New England Journal of Medicine:
Here’s the front cover:
It’s the 200th Anniversary issue, no less. Some might protest that ‘probiotics’—live bacteria of ‘good’ varieties, as far as the gut is concerned—aren’t all that implausible, and that there is some trial evidence that they help for some conditions. That’s true, but as is typically the case even for the somewhat plausible end of the “CAM” spectrum, the hype greatly surpasses the evidence. The abstract of the most recent systematic review that I could find for probiotic treatment of irritable bowel syndrome (IBS: symptoms and signs that best match the claims in the advertisement above) concluded:
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.