Delicious homemade Kimchi (fermented cabbage). It’s alive! Click for a closer look.
Fermented foods, such as sauerkraut and kombucha, have become popular for health reasons. I have made my own sauerkraut in the past and have recently made the tasty, fermented Korean side dish, kimchi. I did it not only for the taste but also for the hope that the bacteria responsible for the fermentation of the cabbage — lactic acid bacteria (LAB) — would contribute to the diversity of my gut microbiota.
As a research scientist in the field of bacterial pathogenesis, this made sense to me. Now that I have started blogging about health and fitness and have been writing more in depth articles about health related topics, I started wondering what research has been done on the health benefits of fermented foods. Can the bacteria in fermented foods even survive the harsh conditions of the human gastrointestinal (GI) tract, particularly the stomach?
I was amazed to learn that the fermentation of food has been used by humans for thousands of years as a way to preserve foods, and that the health benefits go beyond their microorganisms (don’t worry, citations are provided below). The fermentation process enhances the nutritional quality of food by contributing beneficial compounds such as vitamins, and by increasing the bioavailability of minerals. Probiotics, including those found in kimchi, have a range of positive effects on health, including the improvement of various intestinal inflammatory conditions, positive impacts on the immune system and even weight loss, and can alter the composition of the gut microbiome.
However, these effects mostly depend on whether the bacteria actually make it in sufficient numbers to the colon. And let me tell you, the journey to the colon is one harsh and dangerous ride!
Some apparently rather useless Lactobacillus acidophilus
I always cringe when I see an acupuncture headline with ‘needle’ or ‘point’ in the title. Can’t the writer avoid the clichéd pun? I had an editor who commented that the titles of my essays are often obtuse. Probably true. In going back over my essays on SBM I often can’t tell from the title what I have written about until I read the article. It is a fine line between (what I think) is a clever title and obscurity. So gut check it is.
Time flies when you are having fun. I wrote about probiotics back in 2009.
My conclusion at the time:
Probiotics are useful for the prevention of antibiotic-associated diarrhea. Probiotics may be helpful in preventing other overgrowth syndromes or diseases associated, and perhaps with perturbations of the gut microbial flora such as IBS and colic.
Probiotics are foreign bacteria that are not a normal part of your GI tract; they do not enhance your immune system and, in normal people do not promote the nebulous bowel health.
If you are a normal human, with a normal diet, save your money. Probiotics have nothing to offer but an increased cost.
Medicine is not static and there have been interesting advances in the understanding of the human microbiome in health and disease since 2009, so for SBM and my own medical understanding, I thought it would be a good opportunity to review the topic. Although with over 12,000 references on the PubMeds, I will only touch on a smattering of the papers. My ID attending in medical school always referred to reading the medical literature as drinking from a fire hose. Indeed. (more…)
I know by now I shouldn’t be, but I am still amazed by how readily so many people buy into the seemingly endless array of bogus sCAM nostrums. Many are marketed and hawked for the treatment or prevention of diseases that are poorly managed by science-based medicine. There are countless examples of dietary supplements that are purported to effectively treat back and joint pains, depression, anxiety, autism, chronic pain, and chronic fatigue; the list goes on and on. The lure for these treatments is at least understandable and, although frustrated that scientific literacy and rational thought loses out, I empathize with the desire to believe in them. On the other end of the spectrum is the even more ethically corrupt substitution of safe and effective treatments with products that are not. I encountered what I find to be possibly the most frightening and dangerous example of this recently at my practice. A family new to the area called to schedule a routine health-maintenance visit for their 5-year-old daughter. When our nurse reviewed the medical records the mother had faxed over, she noted that the child was unimmunized and explained to her that she would need to begin catch-up vaccinations. The mother matter-of-factly stated that her daughter was actually fully vaccinated with a vaccine alternative. She had received a series of homeopathic vaccines from a naturopath. I am not going to discuss this egregious example of sCAM here, though it was addressed in previous SBM posts.1,2 Instead I’d like to focus on another part of the sCAM spectrum. Here lies a form of sCAM that, in some ways, is even more difficult for me to comprehend. These are products invented, marketed, and sold solely for the treatment or prevention of fictitious diseases or problems that exist only in the realm of fantasy. (more…)
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:
Remember this picture when I start talking about your spouse.
The Wall Street Journal has an assessment of probiotics in the Jan 13, 2009 issue entitled “Bug Crazy: Assessing the Benefits of Probiotics.” For some reason when I wander around the hospital on rounds people show me articles such as this and ask, so whatcha think about this? Probiotics are interesting. They are live bacteria given to treat and prevent diseases. It is one of those overlap areas for scientific medicine and so called alternative medicine. There are good clinical trials to suggest areas where these agents are of benefit, but other aspects of their use are blown out of proportion for the real or imagined benefit probiotics may provide. Much of alternative medicine where it overlaps with real medicine is the art of making therapeutic mountains out of clinical molehills. The Wall Street Journal article is the kind of reporting that drives. Me. Nuts. It drives me nuts because the reporting acts as if the underlying assumptions of the therapies are true. (more…)
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.