 Changes in your diet not only affect you physically, physiologically inside, but also mentally, how well you think, psychologically, how well you feel. But you'll never know just how good you can feel until you put it to the test and try eating healthier. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. Today we look at that surprising versatility of fecal transplants. Did you know they can be used to treat clinical conditions like ulcerative colitis, depression, bipolar disorder, and alcoholism? Here's the story. Plant-based foods and the microbiome and the preservation of health and prevention of disease. We have evidence that high-fiber plant-based diets can prevent many different common diseases, maybe through the effect that these diets have on the composition and metabolic activity of our microbiome, the bacteria in our gut. Good gut bugs in our colon eat the plant residues and spit out health-promoting and cancer-suppressing metabolites. Like fiber is metabolized to short-chain fatty acids, which have profound anti-inflammatory, anti-cancer properties, and we have special fiber-feeding microbes that chew through the plant cell balls and release all the anti-inflammatory, antioxidant, and anti-cancer goodies inside. So, how many old plant foods do we have to eat? All the evidence points to a physiological need for about 50 grams of fiber a day, which is what is contained in the traditional African diet, and is associated with the prevention of common Western chronic diseases. This is up to twice the recommended minimum and three times the current intake in the United States. How can you prove the microbiome is involved, though? Fecal transplantation, stool transplants, one man's trash, another man's treasure. Currently, donor fecal microbiota transplantation is the optimum therapeutic approach for recurrent clostridium difficile infection. C. diff is today considered the most common hospital-acquired cause of diarrhea. It's a life-threatening infection that can rear its ugly head when your good gut bugs have been wiped out by antibiotics. So, to get rid of it, all we need are more good gut bugs, which can be provided by a healthy donor through the infusion of a liquid suspension of the donor's stool. We are winning with poo. Fecal transplants have proven their worth, and the management of recurrent C. diff diarrhea with cure rates up to 90%. Because of this success, fecal transplants have been suggested as a potential treatment in other gastrointestinal diseases. For example, the inflammatory bowel disease known as ulcerative colitis. There have been four randomized controlled trials, and fecal transplants appeared to nearly double clinical remission rates. But what about non-gastrointestinal disorders? Here's a case study of a series of fecal transplants for multiple sclerosis. The patient experienced improvements in their microbiome, more of these fiber-feeding anti-inflammatory bacteria, and there was a significant increase in the levels of brain-derived neurotrophic factor, which is suggested to play a neuroprotective role in MS, as well as both subjective and objective evidence of improved walking, which was the patient's primary MS symptom. Now, to give the new fiber-feeders something to chew on, the patient was put on a high fiber diet, which is great, but just putting people on a plant-based diet alone may help. Stool transplants are not, since standard Western diets promote dysbiosis, a bad bug gut imbalance, and neuroinflammation in MS, while plant-based high-fiber diets decrease MS risks. Randomized placebo-controlled trials will be needed to tease that out, but in the meanwhile, we can certainly build up good gut bugs the old-fashioned way by eating fiber-rich whole-plant foods. What about fecal transplants for depression? Interest in the gut microbiome and its role in health has exploded just in the last few years. Does any of this have relevance in psychiatry? Maybe so. Several studies demonstrate microbiome differences between depressed persons and non-depressed persons, and after all, an imbalance in neurotransmitters is implicated in the cause of depression, and the gut microbiome is known to synthesize large quantities of these same neuroactive supplements, like serotonin and dopamine, and there's a major information highway from the gut to the brain called the vagus nerve that could potentially alter mood states. Early fecal transplants were delivered from the bottom up through colonoscopy, but now we have crapsules, encapsulated feces to make it easier to swap stool. Here's a case report of a 79-year-old woman who suffered a tragedy and subsequently lost her appetite, became introverted, drowsy, and stayed in bed all day, wasting away 55 pounds over the next six months. She was hospitalized for depression and prescribed multiple anti-depressant drugs, but to no avail. So what the heck? They stopped the drugs and tried a fecal transplant. The stool donor was her own 6-year-old great-grandson, who had a good appetite, an outgoing personality, and a disciplinary stool. I don't even know what that means. Four days after the fecal transplant, she started feeling better, and by two weeks, she was frankly euphoric. She was able to go back home and within six weeks, all was back to normal. What about a fecal transplant for bipolar disorder? The poor woman was in and out of psych hospitals with manic depression until she got a fecal transplant with stool from her husband. That's romantic. And within six months, she was symptom-free. This case report was published in 2020, so symptom-free for years, no longer on medication, and has lost more than 70 pounds to boot, either because she got slim hubby stool, or just being off her psych meds. She went from being functionally disabled to running a small business and has published two books. What about alcohol dependence? Alcoholism has traditionally been considered exclusively a brain disorder, but hey, all these other psychiatric syndromes seem to have links to the gut, so they compared the guts of alcoholics to non-alcoholics, and they found that some alcohol-dependent subjects developed gut leachiness, which was associated with higher alcohol cravings. Okay, but maybe instead of the gut issues somehow leading to alcohol cravings, the alcohol led to the gut issues. Alcohol may have a toxic effect on the gut wall, but both groups were consuming the same amount of alcohol at the time, so maybe there is some kind of gut connection after all? This was the study that blew people's minds. The transplant of feces from alcoholics into mice induced an alcohol preference. These were mice without any previous contact with alcohol, all of a sudden spontaneously preferring alcohol. Normally, mice don't really like alcohol, but feed them some feces from an alcoholic human, and they do a 180-degree switch. So wait, are you saying that gut bugs can determine alcohol cravings? There's only one way to find out, and that's put it to the test. A randomized double-blind clinical trial, a fecal microbiota transplant for alcohol use disorder, which is the current clinical term for alcoholism. They took alcoholics with liver cirrhosis and active problem drinking and randomized them to either get a placebo enema or a fecal transplant enema, and within two weeks, alcohol cravings reduced significantly in 90% of the fecal transplant cases versus just 30% in the placebo cases. And this was validated by P-Tests, showing that they were drinking significantly less, too, with improved cognition and psychosocial quality of life. Now this is all still just experimental, and not without potential downsides. Yes, they're working on ways to make stool transplants more palatable. On balance, they've largely been found to be safe, though there have been cases of bad bugs being transferred from donors, even a fatal case. And there's even a theoretical risk you could be transplanted with cancer cells, making it the gift that keeps on giving, but in a bad way. In our next story, we look at what's more important, probiotics or prebiotics, and where can we best get them? Virtually every day we are all confronted with the activity of our intestine, and it's no surprise that at least some of us have developed a fascination with our intestinal condition and its relation to health and disease. Over the last years, the intestinal microbiota or gut flora has been identified as like a fascinating new organ with all sorts of functions. Well, if the bacteria in our gut make up like a whole separate organ inside our body, what about doing an organ transplant? What would happen if you transferred intestinal bacteria from lean people into obese people? Researchers figured that rebalancing the obesity-causing bacteria with an infusion of gut bacteria from a lean person might help. Now, they want this to be a placebo-controlled study, which for drugs is easy, give a sugar pill. But when you're sticking a tube down people's throats and transplanting feces, I'm thinking, what do you use as a poop-cebo, if you will? Both the donors and the subject brought in fresh stools, and the subjects are randomized to either get the donor stool or get transplanted with their own collected feces. That was the placebo, you get your own back. Okay, so what happened? The insulin sensitivity of the skinny donors was up around 50. That's a good thing. High insulin sensitivity means low insulin resistance, the cause of both type 2 diabetes and pre-diabetes. The obese subjects started out around 20, and after infusion of their own feces they stayed around 20. But the group of obese donors getting the skinny similarly started out low, but shot up near to where the slim folks were. It's interesting, not all lean donor stools conveyed the same effect on insulin sensitivity, as some donors had very significant effects, the so-called super fecal donor, whereas others had little or no effect. Turns out this super donor effect is most probably conveyed by the amounts of short chain fatty acid producing intestinal bacteria in their feces, the food bacteria that thrive off of the fiber we eat. The short chain fatty acids produced by fiber-eating bacteria may contribute to the release of gut hormones that may be the cause of this beneficial improved insulin sensitivity. The successful use of fecal transplantation has recently attracted considerable attention, not only because of its success, but its capacity to prove the cause-and-effect relationship that the bacteria we have in our gut can affect our metabolism. But within a few months the bacterial composition returned back to baseline, so the effects on the obese subjects were temporary. We can get similar benefits, though, by just feeding what few good gut bacteria we may already have. Say you have a shed full of bunny rabbits. Feed them pork rinds, and they all die. Yes, you can repopulate your shed by infusing new bunnies, but if you keep feeding them pork rinds, they'll eventually die off as well, whereas even if you start off with just a few bunnies, if you feed them what they're meant to eat, they'll grow and multiply, and soon you'll be full of fiber-eating bunnies. Fecal transplants and probiotics are only temporary fixes if we keep putting the wrong fuel into our gut, but by feeding prebiotics, such as fiber, which means increasing whole plant food consumption, we may select for and foster the growth of our own good bacteria. However, such effects may abate once the high fiber intake ceases. Therefore, our dietary habits should include a continuous consumption of large quantities of high fiber foods to improve our health, and if we don't, we may be starving our microbial cell. We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to nutritionfacts.org slash testimonials which may be able to share it on social media to help inspire others. If you'd like to see any of the graphs, charts, graphics, images, or studies mentioned here, go to the Nutrition Facts Podcast landing page where you'll find all the detailed information you need, plus links to all the sources we cite for each of these topics. My last two books were How to Survive a Pandemic and My How Not to Diet Cookbook. Get ready this year for the launch of How Not to Age, and of course all the proceeds for the sales of all my books goes directly to charity. Nutritionfacts.org is a non-profit science-based public service where you can sign up for free daily updates on the latest new nutrition research with bite-sized videos and articles uploaded nearly every day. Everything on the website is free. There are no ads, no corporate sponsorships, no kickbacks. It's strictly non-commercial, not selling anything. I just put it up as a public service, as a labor of love as a tribute to my grandmother, whose own life was saved with evidence-based nutrition.