Transcription
what we're talking about here is bacteria. The microbiome is really an ecosystem of about 39 trillion bacteria that live in our gut. They actually live all over our body, in every orifice—your ears, your nostrils, your mouth, your anus. I mean, every place there's an opening, there's bacteria. But here's a crazy thing: inside our body, we're packed with bacteria at the lower end of our gut. The home, the Great Barrier Reef of these natural bacteria in our body, is in a part of the colon called the cecum. If you're in the medical field, you'll know exactly what I'm talking about. It's a part of the organ system that a lot of people aren't familiar with. I used to wonder, "Okay, so where does the microbiome, where do all these bacteria live?" It's called the cecum.
There are some bacteria that are really bad actors, and they cause all kinds of problems. But by and large, most of the bacteria that we will encounter in our lives are inside our body, not outside our body, and most of the bacteria are good, not bad. That's what we call our gut microbiome. Our gut microbiome actually is an ecosystem of 39 trillion bacteria, most of it living inside our gut. What they do inside our gut is they eat the food that our body doesn't digest.
Let me explain. You take a bite of an apple, and our human bodies are going to absorb the natural fructose, the sugars in the apple. We're going to get the vitamins; we're actually going to get some of the other nutrients that are going to be absorbed into our body. But there's a lot of fiber that's going to be left over, right? You know, the skin that you eat if it's an organic apple. The fiber—there's a lot of fiber in an apple or pear—and then that fiber trickles down your 40 feet of intestine all the way to the cecum. The bacteria there are being fed this leftover stuff. Whatever we don't absorb goes to the bacteria.
I'm going to come back to that point because you're asking why the chemicals are not so good for us. It's because our bacteria get fed. If it's normal, healthy food, normal, healthy fiber, our bacteria eat that fiber, and in payback for feeding them, the love that our bacteria show for us is that they produce metabolites that are anti-inflammatory. These are called short-chain fatty acids, or SCFAs, and they lower inflammation, promote healing, streamline our blood lipids, and make our insulin sensitivity better, which is an important part of our metabolism.
So the fuel is actually more rapidly absorbed into our bloodstream. Nobody wants to have lots of glucose, lots of blood sugar at high levels all day long. It's not good for our bodies. It's like being stuck in a bathtub too long or a swimming pool too long. You know how your fingers wrinkle? That's not what you want. You want our blood sugar to be readily absorbed into our cells. These are just partially what we know our gut bacteria does for us.
So we have to feed them well. Feeding them three times a day is kind of like having a pet. Our bacteria, our microbiome, is like a pet. If you have a dog, a cat, a parakeet, a goldfish, most of us are responsible pet owners, so we make sure that we feed them our kibble or the flakes every single day or the seeds. Now, most of us will choose what kind of food we're actually feeding our pet. You don't want to feed your dog junk, right? You want to choose carefully; you want to take care of your animal. Well, that's basically what eating whole foods that are as good as possible—high-quality whole foods—is. That's what we're feeding our gut microbiome.
And they pay us back by giving us health through these short-chain fatty acids. Okay, let's go back to your question: what about foods that are loaded with synthetic chemicals, artificial preservatives, and artificial sweeteners? By the way, it's another big offender. What happens is that we're eating it. "Oh, there's no calories in artificial sweetener." "Oh, this cheap, shelf-stable stuff with artificial flavor tastes really great." It goes down the gullet. We absorb relatively little because it doesn't have as many nutrients as the normal whole food. The rest of it—where does it go? We don't just poop it out; we're feeding our gut bacteria, that 39 trillion population, and we're feeding them junk. We're feeding them chemicals; we're feeding them things that they shouldn't be eating.
Okay, imagine if you fed your pet dog really terrible quality food, chemical food, all the time. I don't think your dog is going to last that long. All the problems that your vet tells you that dogs can have if you feed them poor-quality food—that's what we're doing to our gut with all these artificial synthetic things. And so that's the reason why we need to take good care. You know, like this whole idea of the pregnant mom saying, "I have to watch what I eat because I'm eating for two." Well, guess what? Each of us, we're eating for 39 trillion. In fact, we are feeding our gut microbiome, and we have that responsibility. If we treat our gut microbiome well, they will treat our health well.
So, what are some of the things we can do to make sure our microbiome is thriving? First of all, what do some of the bad substances, the bad actors, the chemicals do? They kill off good bacteria. When good bacteria get killed off, bad bacteria start to grow in. It's an ecosystem, right? So think about the Great Barrier Reef. I've actually had the privilege of swimming in, diving in, and snorkeling around there. It's amazing. You go into the water, and you see this dizzying array of colorful sea life. If you start removing the moray eels, taking the crabs away, and removing the clownfish and taking away the sea anemones, those are all critical players in the gut microbiome.
What do you think is going to grow into that space? Something will grow into it, and in the case of our gut microbiome, it's the bad bacteria that replace the good bacteria. They overgrow. When you have a lot of bad bacteria growing, they produce inflammatory compounds, not anti-inflammatory compounds. They start to create inflammation, and some of these bad bacteria, by the way, can drill their way through your healthy gut and even get into your bloodstream, which is really, really dangerous. In fact, there's one called C. diff (Clostridium difficile), which is a big, deadly problem in hospitals that can cause terrible inflammatory changes in your gut. You have to be on IV antibiotics, and some people don't make it when they have that kind of infection.
So that's why the overgrowth of bad bacteria is a terrible thing. We believe that a lot of irritable bowel syndrome, inflammatory gut disease, and even colon cancers and gut cancers are probably at least partly attributable to harmful overgrowth of bad bacteria. And that's just in the gut. We also know that when you have harmful bacteria growing in your gut, it raises the chances of actually having heart disease, diabetes, and even Alzheimer's disease because of the gut-brain axis. There's a connection between the two. Bad actors in your gut cause bad consequences everywhere in your body.
This is such a new, important field that we only understand the tip of the iceberg. If I were advising a young medical student going into their career right now and they asked me, "Hey, Dr. Lee, what kind of research field should I go into?" I would say, "Go study the microbiome." There's a whole vast frontier out there that teaches us how important our gut bacteria are for our health.
So what are some of the good things that you can actually do? We talked a lot about the bad things. I'm always about the positive side. Don't tell me about just a problem if you can't give me a solution, right? So the solution is this: feed our good gut bacteria to restore their integrity and help the good guys grow back.
Think about it this way: you have a perfectly good neighborhood, and some of the residents there get older and older, they age out, and they die or move away. Now you've got gang members and drug dealers that move in. That's the overgrowth of bad bacteria. What do you think those drug dealers and gang members are going to do? They're going to attract more drug dealers and more gang members into the community, and well, there goes the neighborhood. That's what happens when you have an overgrowth of this bad bacteria.
So what do you do? How do you rehab a neighborhood? What's the good move? Well, look, you've got to move some of the bad guys out, that's for sure. But then what you want to do is you want to move lots of good guys back into the neighborhood because you can actually rehab a downtrodden neighborhood by making the places nicer and moving in people that deserve to be there, who can be good citizens.
How do we do that for our gut bacteria? We start eating more whole, plant-based foods. We eat fiber; we eat good bioactives. We eat the positive bioactives in whole foods. We cut down on chemicals, synthetic chemicals, artificial sweeteners, and artificial flavors. We try to grow back the good guys, and the bad guys will start to go away because good guys can overgrow. They can actually dominate if you give them the opportunity.
So what we can do is eat three types of foods. Number one, we can eat prebiotic foods. These are foods with a lot of dietary fiber: broccoli, apples, lots of fruits, pears, mushrooms, celery, kale, lots of these green veggies, red bell peppers, green peppers, and onions. They all contain lots of dietary fiber. Awesome! Great! Good for you. Even bamboo shoots that you might get in an Asian market, for example, are also a great way of getting dietary fiber. That's why pandas eat bamboo, by the way—they get the dietary fiber.
You can also eat bacteria itself. So, bacteria in foods—again, we were always told if you look in your fridge and you see some blue stuff growing on your food, toss it out. True, please do that; you don't want to be getting food poisoning. But there are certain foods that have good bacteria in them. What kind of foods? Yogurt—it's made with good bacteria. Kimchi, sauerkraut, pickles—all made with good, healthy bacteria. Even some cheeses, which have a lot of saturated fat and salt, are not really healthy for you, but even some of the cheeses can actually have good bacteria that are growing.
Sourdough bread—you know, I'm not telling people to eat a lot of carbs or eat a lot of bread, but if you're going to eat bread, sourdough is the way to go. That tangy, characteristic flavor of sourdough bread is made by lactic acid. How do you get the lactic acid in sourdough bread? You have a good, healthy bacteria that should be growing in our gut called Lactobacillus. Lactobacillus is that kind of bacteria that makes lactic acid, which makes sourdough taste tangy. The bacteria remnants are in that bread, and when you eat them, you're actually replenishing your body by contributing to the ecosystem.
Then, of course, there's something called postbiotics. Postbiotics are really whatever the bacteria produces. Can we actually add some of that into our system as well? Well, it turns out a jar of pickles, a jar of kimchi, or a jar of sauerkraut already has postbiotics because the bacteria already in there are already making their stuff. So we're already eating some of that good stuff.
I think that's really the thing to do: stay away from the bad things for your gut microbiome and add some of the good things for your gut microbiome. One last point about this is that what makes our gut microbiome happiest? It turns out it's not just plant-based foods, but diversity. If you eat the same thing every single day, your gut bacteria gets really bored and doesn't like it. So try to eat 20 or 30 different kinds of plant-based foods every week.
All right, not that hard to do. Spices count! You know, put some seasoning on there; it might be four or five plant-based foods already in a salad. Use more than romaine lettuce; put different kinds of greens in there. Light them up! Diversity is what our gut microbiome thrives on. This is where I think that this idea of loving your food and loving your health comes into play. This is not about being a robot and following only one or two foods. You have to eat a lot of different foods all the time.
Look at all these foods I write about—more than 200 foods that can help beat disease. All of them come from traditional food traditions that you can combine and make absolutely delicious and tasty. That's actually how you get this diversity, which your gut microbiome will thank you for. More diverse foods mean more diverse bacteria, which means a healthier microbiome, which means an overall healthier body.
If you eat a healthy food like a kiwi, for example, that has a lot of dietary fiber, it will cause your gut microbiome to grow healthy bacteria within 24 hours. So it doesn't take much to actually start the process of rehab going. That's really what we're talking about—it's a process. Of course, you do want to actually cut down or cut out the bad stuff because if you're just shoveling in harmful things to your gut microbiome, you're not giving it a chance to recover.
You want to back off the bad stuff and start the good stuff, and it's pretty quick. You can usually get a replenishment of your gut microbiome. These days, by the way, Jesse, you can actually order out and send out your stool sample to have your own gut microbiome checked. Things are beginning to change. It's not mainstream yet, and maybe some of the tests aren't quite ready for prime time, but it's a really useful way for us to be able to monitor our own health by looking for those healthy gut bacteria.
Well, that's great! I just want to make sure what I'm getting at specifically, though, is the assumption that there are still, even if we've abused the microbiome, certain seeds and bits of the good bacteria that we put the right stuff in, those bloom and take up adequate space like they should. Or is it actually bacteria that are coming off the fermented food or just bacteria in our environment that we're taking in that are repopulating from ground zero?
It's actually a little bit of all the above. So it's the good bacteria getting an edge once again to grow back and fill up the spot that they want to fill up. It's the good bacteria that you're eating in the foods that have actually been consumed. By the way, kimchi has two bacteria that have been newly discovered—new to the biology world—that are present only in kimchi. I was really surprised. I'm not Korean, but I do like kimchi. One of them actually fights influenza; it is a bacteria that helps us resist the flu. Another one actually helps us improve our metabolism.
So there are these unique bacteria that grow in foods that are actually really good for us. Yes, we want to be able to eat some of those, and they stick and grow. The ones that are good already can actually grow back and expand more. Of course, we're being in contact with bacteria all the time anyway in our environment.
You know, one of the things we're starting to realize is that living in a sterile environment is not so good for us. We need to be participating in our planet, which is not so much a dirty planet. I mean, well, maybe it is a dirty planet, but basically, we need to actually be in contact with and be at one with the different kinds of bacteria out there. So if you have a kid, let them play in the dirt a little bit. They're actually getting some good bacteria from the planet to help keep their gut healthy, keeping it challenged to make sure it's in good shape.
And Dr. Lee, I know probiotics—I believe in them. A probiotic is really a mix, tends to be a mix of bacteria that we're just adding to the good guys that are in our gut. I don't think a probiotic should be a replacement, however, for fibrous foods, you know, the prebiotic foods or the probiotic foods, because you get so much more.
This is what you call the pure bacteria. Yeah, probably helpful; I believe in it. But you know, you get so much more from those healthy bioactives that are present in whole food. That's actually what I want people to focus on: what are the whole foods that you really enjoy? This isn't a chore; this is all about enjoying your health and enjoying your food at the same time. You can actually pick from a menu of foods that are actually good for you. Don't eat the ones you don't like, for God's sake. Choose the ones that you actually love, and pick a lot of different ones. Vary it up! Enjoy it!
I really try to coach people into not being afraid of food but leaning into food—not worrying so much about the things that can harm them, but really focusing on which foods that you enjoy can actually bring you benefit. Because that's a win-win situation when you find a food that you enjoy and it's good for you.
You touched on the fact that our microbiome is in communication with different areas of the body. I want to hone in on the communication between the gut and the brain. This is something that comes up on the show periodically, but you're a guy that likes to go deep into the science. So I'm curious: how does that work?
You know, it's so interesting. We don't fully understand it, but I'll tell you what we believe is happening. Okay, let me set the stage by first painting a picture of how the gut and the brain are wired together. Out of our brain, we've got nerves that come out of our brain. Our brain is like tens of millions of nerves, but there are these cranial nerves that pop out like wires coming out of the wall. One of them, one of the biggest nerves, is called the vagus nerve. It's one of the biggest nerves in the body. It comes out of your head, runs down your neck, wraps around your esophagus, which is the tube that we eat with, to our stomach.
Then below that, it branches out into thousands of branches. Those branches reach all the way down to our intestines. It's kind of like a horse's tail blowing in the wind. You've got all these tendrils everywhere, and they're touching our gut. What we believe is that the brain signals to the gut through these nerves that talk to the bacteria, and vice versa. The bacteria can send a text message up to the brain through the vagus nerve.
Okay, so you think about the bacteria living inside your gut. There's a gut wall, and then just on the other side is a wire. The bacteria can actually just put a signal right through the wire. This is a wired system, not a wireless system, and it goes up into the brain. Of course, bacteria can also send wireless signals through the bloodstream.
What happens is that when the brain receives those bacterial signals, they begin to release hormones, social hormones being one of the most important. There's one called oxytocin. Some of your viewers and listeners may have heard of oxytocin. Oxytocin is a social hormone. It is the hormone that your brain surges and releases when you see a great friend that you haven't seen for a long time. You think, "Oh my God, I feel so good seeing that person!" Or when you give a family member a hug, you know, a family member you like—a hug—you feel good. That's oxytocin.
Oxytocin is what you actually get—not with a peck on the lips with a kiss, but a French kiss. Your brain floods out oxytocin. The biggest example everyone always remembers when I say this is that when you have an orgasm, your brain pounds out a gigantic burst of oxytocin. It's just there for a few seconds, but that's what makes you feel so great for a short period of time.
Okay, the gut microbiome is connected, communicating through this vagus nerve up into your brain and triggering, sending text messages: "Hey, a little oxytocin, please! A little more oxytocin, please!" It actually helps us keep our mood going up. That's an example. Oxytocin is just one of them. Serotonin, dopamine—these are all the things that psychiatrists have been writing prescriptions for for decades to try to improve mood.
You know, I think that we're beginning to realize that our gut bacteria actually play a role in improving our mood. Now we're beginning to think...