Most people don’t realize they share their bodies with trillions of bacteria, fungi and other microbes. The majority of these live deep within our intestines and are known collectively as the gut microbiome.
“The microbiome is the collection of bacteria that live in the GI (gastrointestinal) tract, predominantly in the colon,” explains Seth Rosen, M.D.,  a gastroenterologist affiliated with Baptist Health South Florida. “They are necessary for healthy functioning. And it’s a very normal situation to have all of these bacteria from the time shortly after you’re born until you die. And when there are alterations in there it can lead to illness.”
So-called healthy bacteria in the gut microbiome produce vitamins including vitamins B, B-12, thiamin, and riboflavin, and help keep unhealthy bacteria in check. Numerous studies in recent years have found that the health of the gut microbiome plays a role beyond our digestive system and may affect conditions including diabetes, obesity, heart disease and cancer.
Dr. Rosen shed light on the unseen world of the gut microbiome on a recent episode of the Baptist HealthTalk podcast , hosted by Jonathan Fialkow, M.D.,  deputy medical director and chief of cardiology at Miami Cardiac & Vascular Institute . Check out some illuminating Q&A highlights from their discussion.
Dr. Fialkow: What are some of the more common medical conditions that we are now doing a lot of research about and raising interest regarding the role of the microbiome?
“Well, it’s been talked about in a variety of situations. Most commonly in irritable bowel syndrome, where the balance of the organisms seems to play a key role. It’s also been implicated in Clostridium difficile (C difficile) or pseudomembranous colitis, which you get after you’ve taken antibiotics.”
Dr. Fialkow: And those are really significant diarrheal illnesses, right?
“Yes. There’s been talk about Inflammatory Bowel Diseases, such as Crohn’s disease and ulcerative colitis. And it’s also seems to play a key role in the balance of the immune system in the body and generalized inflammation in the body. An imbalance has been implicated in possibly increasing inflammatory markers and leading to heart disease.”
Dr. Fialkow: Right. We think the bacteria protect us against and provide a barrier against certain substances, which otherwise can be absorbed and cause inflammation, and heart disease, and cancer, and even obesity. They’re thinking that there might be a connection between why certain people can eat food and then bacteria digests in a certain way that increases the absorption of the food and may lead to obesity and various other things. So, it’s just fascinating. What do we see with the microbiome in relation to antibiotic use?
“So, whenever you take antibiotics you’re going to alter the bacteria balance in your GI tract. The antibiotics, especially the ones we use today, what we call broad spectrum, broad acting against many different bacterial species, will alter the balance of bacteria in the GI tract. And the result of that can create different conditions. Some people, while they’re taking antibiotics, will have diarrhea. Some will have gas and bloating; some will have constipation. And this is all because you’ve altered that very critical balance of bacteria that exists in the GI tract.”
Dr. Fialkow: So, let’s talk a little bit about probiotics.
“Probiotics are so-called healthy bacteria for the GI tract. There are literally dozens and dozens of probiotic products on the market. The first thing people need to know is these are not treated as drugs by the FDA. The U.S. Food and Drug Administration classifies these as supplements or food supplements. And so, they don’t go through the same rigorous testing that a drug will go through. The only requirement that a company has is to make sure that they’re safe and won’t harm people. But there is no requirement to show that there’s truly a benefit to them.
“Some of the probiotics have done clinical studies and shown that there may be a benefit. And often these clinical studies are concentrating on a specific disease condition, either diarrhea or irritable bowel syndrome, or perhaps even inflammatory bowel disease. But any of the probiotics that say “We will just improve your health,” are probably lacking any solid scientific evidence.”
Dr. Fialkow: Are there situations in which you recommend probiotics to your patients?
“I may recommend probiotics when I want to treat a specific condition where I think the probiotic may be beneficial and then I’ll try and select the probiotic. And there’s only a handful that there have really been clinical studies on. I’ll choose one where there’s some data that supports treating that particular condition.
“People who aren’t having any problems and come in for colon cancer screening and they’ll say, “Should I be on a probiotic?” If they have no issues then there’s no particular reason for them to spend their money on a probiotic. They tend to actually to be rather expensive, actually.”
Dr. Fialkow: What about natural probiotics? Do you recommend any kind of dietary components that either are felt or shown to be a benefit?
“People will say to me, “Well, I eat yogurt and it says, it’s got probiotics in it.” The problem is you can’t eat enough yogurt that really make a dent in your microbiome. What has been shown are what are called prebiotics, which are certain healthy foods that act to stimulate the growth of the healthy bacteria in the GI track. Certain fibers are good for that. Somebody’s looked at dandelion extract, which is good for it. Cauliflower and broccoli have all been suggested to be healthy prebiotics. And you can buy supplements that are touted as being prebiotics. They do not have probiotics in them, but they will stimulate the healthy bacteria in the GI tract.”
Dr. Fialkow: So, my staple of my diet of eating purely yogurt, sauerkraut, and kimchi is not going to work if I have a diarrheal illness from an antibiotic?
“It’s unlikely to. Actually, (I will) play devil’s advocate. There was a study that came out last year that questioned the efficacy of any probiotics. You take a probiotic and it’s got a couple of million colonies of bacteria in it. And you’re talking about billions and billions in the GI track, or trillions. Does it make a difference if you take a pill every day with a couple of million colonies of bacteria in it, and it has to make its way through your GI tract to get to the lower portion of your GI tract?
“And some people have questioned whether it makes any difference whatsoever in scientific studies. The problem with the kimchi and the yogurt is that it has far less than what is in these little capsules. And so, no, you can’t eat enough, although those are all healthy things.”
Dr. Fialkow: Let’s get to antibiotics. We know that we should not take antibiotics if we don’t absolutely need them.
“We use way too many antibiotics in this country. And there’s no question that it is detrimental to health when they’re overused. So that’s the first thing.
“Another thing is there are many, many people who are on proton pump Inhibitors, that’s Nexium, and pantoprazole, Protonix, Prilosec, omeprazole. Those are the proton pump Inhibitors. They shut down acid in the stomach, which is one of our early first defenses against bad bacteria. And it’s been shown that people who are on this for a long-term may have more issues with their gut biome, and in the setting of using antibiotics, they may be more prone to certain illnesses, including C difficile. So, I would say the same thing about proton pump Inhibitors as antibiotics. Don’t use them unless they’re absolutely indicated.”