Our Guts and Brain: The Connection Between Digestive Health and Mental Health with Dr. Benjamin Lebwohl
A gastroenterologist describes how the health of our digestive tract can have implications for mental health, and what anyone can do to support their digestive health.
Welcome to Health Matters – your weekly dose of the latest in health and wellness from NewYork-Presbyterian. I’m Faith Salie.
In today’s episode, we’re exploring the science behind that feeling of having butterflies in your stomach.
The connection between what we feel in our guts and how we feel in our brains — which doctors call the gut-brain axis — is so much stronger than you might think.
To explore that fascinating link, I talked with Dr. Benjamin Lebwohl, a gastroenterologist at NewYork-Presbyterian and Columbia. He’s also the Director of Clinical Research at Columbia’s Celiac Disease Center, so he took us through the ins and outs of our gut health, and explained how GI diseases like Celiac have implications for our mental health.
Faith: Hi, Dr. Lebwohl. Thank you so much for joining us.
Dr. Lebwohl: Thank you, Faith. It’s nice to be here.
Faith: As a gastroenterologist, you treat a host of GI conditions, from heart burn to Celiac disease, which we’ll talk more about later. But let’s start by discussing the connection between gastrointestinal health and mental health. Could you explain the gut-brain axis for us?
Dr. Lebwohl: Sure the gut brain axis refers to the strong connection between the workings of the gut, of the gastrointestinal tract and the doings of our consciousness and our awareness. We all have a gut-brain axis. In a state of good health the gut sends a message to our conscious awareness saying, oh, it’s time for you to go to the bathroom. And that is your gut brain access at work. In other situations, it’s not originating from the gut, but it’s originating from something you are seeing or experiencing. We’ve all had the notion of having butterflies in one’s stomach, so that is the phenomenon where some stressful circumstance, whether it’s a big exam coming up, public speaking, whatever it is that might make you somewhat anxious. Often that is accompanied by some sensation of queasiness.
Faith: We are so used to talking about our gut metaphorically. Right. I don’t know, man. I just feel it in my gut. And what you’re telling us is that’s real.
Dr. Lebwohl: Yeah, it is. So you know, the other expressions, oh, that person has got a lot of guts. You know, a lot of, but yeah, there’s a close connection between times of stress and gut function.
Faith: Is this a relatively new phrase, gut-brain axis?
Dr. Lebwohl: Actually a lot of this work was pioneered by a physician named Michael Gershon, who’s here at New York Presbyterian/Columbia, who wrote a book some years ago called the Second Brain, referring to our guts, and this reflects the finding that we have a tremendous amount of neural activity originating from the gastrointestinal tract.
In fact, serotonin, which is a neurotransmitter kind of chemical that neurons use to communicate with each other -and increasing serotonin is seen to be beneficial for mood- it turns out that in our body there’s a lot more serotonin in our gut than in our brain. And so that in part explains this sort of emotional connection we might have with our gastrointestinal tract.
But it’s also a fact that often, this second brain is occurring at a level unbeknownst to our consciousness. I remember being a medical student and watching for the first time an upper endoscopy and a colonoscopy looking at the inner workings of the stomach, the small intestine, and the large intestine, the colon.
And what struck me as a first-time observer of this was that the patient was asleep, deeply asleep and unaware, and yet the gut was contracting, in an almost sort of reptilian way. You see these waves of muscle contraction and relaxation. That is of course, happening without our knowledge. That’s how food gets through us and we’re not feeling every single one of those contractions, but that’s actually happening all the time, including when we’re totally unconscious during a colonoscopy. That really got me sort of, a real appreciation of the fact that the gut really does have its own nervous system.
Faith: Everything you’re saying is giving me this new profound respect for our guts.
Dr. Lebwohl: You know, like any part of the body or, or system we don’t think about it or appreciate it unless or until it’s not working properly.
Faith: Using a couple of diseases as examples—like Crohn’s disease or irritable bowel syndrome—what are some of the mental health implications of GI distress?
Dr. Lebwohl: So these different conditions can cause symptoms in a little bit different ways. But ultimately their toll on mental health can be similar. And so for example, in irritable bowel syndrome, which we believe is fundamentally a disorder of this brain-gut axis where, otherwise innocuous stimuli in the gut is being interpreted by the nerve endings in the gut as severe pain. That can cause, maybe the feeling like you have to use the bathroom and can interfere with your quality of life and your ability to function. In Crohn’s disease where there’s inflammation, where the immune system is really acting up in response to something in the bowel, probably our community of bacteria that otherwise, you know, uh, are not causing trouble. In Crohn’s disease, the immune system is reacting against that and resulting actually in direct damage to the gut. In celiac disease, someone who is exposed to gluten, the immune system sees that as a threat, attacks the gluten that’s in the bowel, and the gut is collateral damage. It directly becomes affected by the immune system. And again, with a damaged gut that interferes with its ability to process and absorb nutrients.
Now, all these different ways in which the gut might malfunction can result in a very unhappy host, right? Suddenly the owner of the gut is getting all of this distress, feeling pain, feeling the need to go to the bathroom and that in turn can result in great distress, which can sometimes lead to even more gastrointestinal problems.
Faith: In our culture, these are conditions that people don’t feel comfortable talking about, and that must have really difficult mental health impact.
Dr. Lebwohl: That’s right. And so gastrointestinal problems, if they interfere with ordinary social discourse, with going out to eat or going on a date, it can be stigmatizing, it can be embarrassing. And someone who’s really in the throes of, you know, an uncontrolled flare-up of Crohn’s disease, or is having difficulty because of incompletely controlled celiac disease, they might prefer to avoid social interaction.
It’s actually something that I’m seeing a lot in celiac disease where traveling and eating out, these are the circumstances wherein someone with this condition might be particularly concerned because unlike a home-cooked meal, you’re not sure if there might be small amounts of gluten in the restaurant meal that you’re about to have, or if you’re going to someone’s home, you don’t want to make a big fuss and tell them all of the ways that you need to avoid cross contact with gluten. And so, that runs the risk of closing off aspects of life that are really important to us.
Faith: You’ve mentioned celiac disease and you’ve described what it is. How is it diagnosed?
Dr. Lebwohl: About one in a hundred of us have celiac disease, but many people with celiac disease remain undiagnosed. They don’t know that they have it. Some people with celiac disease are having ongoing gastrointestinal symptoms, abdominal pain, irregular bowel habits, and in light of our relatively recent understanding that celiac disease is common and can have many different symptoms. The way it’s diagnosed is typically a combination of blood tests and an intestinal biopsy, which is a sample of the intestine that’s obtained during an upper gastrointestinal endoscopy.
And celiac disease has a very characteristic appearance of a damaged intestine. So if someone has an elevated antibody level and that intestinal appearance, then a diagnosis is confirmed and that’s when the gluten-free diet should be begun.
What’s key is to do the testing first. It’s very tempting to start a gluten-free diet because you’re looking for answers, you’re not feeling well. But if you wanna figure out if celiac disease is indeed the problem, the root of symptoms, it’s really important to do this testing first.
Faith: Are there any symptoms of celiac that might surprise people?
Dr. Lebwohl: It is diagnosed in the gut, but it can affect multiple different parts of the body. In some ways, that’s a consequence of the gut not working. For example, if the gut isn’t working properly, we can’t absorb calcium and vitamin D, and someone might be diagnosed with celiac disease after they have a fracture and they’re found to have, for example, a young onset osteoporosis, and they might not even have much or even any disturbance in their bowel function.
Another person might get diagnosed after they are found on routine blood tests to have anemia, to have a low blood count. And that’s because we need a functioning gut to absorb dietary iron. And if celiac disease is present and if the person is continuing to eat gluten their malfunctioning gut won’t absorb iron properly, and they may develop anemia, even again in the absence of intestinal symptoms.
Still others may have symptoms that seem far flung and nothing to do with the intestinal tract, including migraines, including infertility, including elevated liver enzymes on routine blood tests. So all these are different manifestations of celiac disease. It really can be what we call a clinical chameleon and it can be a challenge to get diagnosed if someone with celiac disease doesn’t have the so-called classical symptoms of irregular bowel habits, abdominal pain.
Faith: So it’s clear that for celiacs in particular, avoiding gluten, right? Wheat, rye, barley, that’s a big don’t, but health as we know is more than just avoiding the bad stuff. So, what are the most important things on the do list for someone with Celiac when it comes to supporting gut health?
Dr. Lebwohl: I’m glad you asked because the gluten-free diet really is not just about what to avoid. It’s fundamentally about how to have a healthy diet and what to eat. And one of the benefits of coming to a Celiac Disease Center like the one we have at our institution is access to expert dieticians who can really sit down and discuss how to have a gluten-free diet that’s healthy, that’s sufficiently diverse, that’s sufficient in whole grains, which is a component of a gluten-free diet that sometimes plummets if done without careful guidance. And also one that is sufficiently interesting. So it’s really important to play the long game here and think about this being a long-term treatment.
Faith: What are some things that anyone can do to strengthen their GI health and thus support their mental health?
Dr. Lebwohl: The most important thing anyone can do is be up to date with their screenings. And in the GI world, that’s colorectal cancer screening. That is the gastrointestinal cancer that we screen everyone, even if they feel perfectly well, for.
It’s important to underscore that colon cancer is really common. Five percent of us will get it in our lifetime. That’s one in 20, and the most common symptom of early colon cancer is no symptom. You feel perfectly fine. And that’s where screening comes in.
If colon cancer reliably caused a specific kind of symptom early on, like rectal bleeding, if it always caused that, we wouldn’t be screening. But in fact, usually it doesn’t cause that, doesn’t cause any symptom, and that’s why we say, you should come in when it’s time for you to come in, even if you feel fine.
Faith: Dr. Lewohl, thank you. That’s such an important takeaway for all of us. I’m so glad to talk with you.
Dr. Lebwohl: It’s my pleasure. Thank you.
Our thanks to Dr. Lebwohl
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