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Why We Actually Need Bacteria to Stay Healthy
Interviewer: Living on the inside and outside of our bodies are over 1000 species of bacteria. It may sound creepy, but as it turns out, our microbiota, as they are called, keep us healthy.
Pathology Professor, studies how the bacteria help us. Dr. Round, why does our body need these bacteria?
Dr. Round: We're still trying to better understand why we need these bacteria, but there's a lot of studies to support that these bacteria are very important in influencing the development of our immune system, which helps us to fight off the bad organisms and protect us from diseases. There are also studies to show that these organisms are important for maintaining a healthy weight, as well as protecting us from even diseases like autism. So they can even influence how we behave.
Your Microbiota Is as Unique as Your Fingerprint
Interviewer: Does everyone have the same type of bacteria in them?
Dr. Round: Actually, everyone's microbiota is very much like a fingerprint. No two are exactly alike. Even twins, their microbiota is different despite the fact that they're genetically identical.
How Good Bacteria Train Your Immune System
Interviewer: You focus on how these bacteria interact with the immune system. Why is this work interest interesting to you?
Dr. Round: I was a trained immunologist. And when I was doing my graduate studies at UCLA, when I was learning about the immune system, I was learning about how the immune system evolved to fight off bad bacteria. And that's all I thought about during my graduate studies.
But in thinking about these commensal microbes that live all over our bodies, it got me thinking that, well, maybe there's something more to it. We're actually finding that these organisms are imperative to the development of a healthy immune response. They actually teach our immune system how to be better at fighting off the bad ones, and they help our immune system to discriminate what is good and what is bad, and help us to tolerate the things that we need to be tolerant against, and by tolerance I mean to not mount an immune response against.
What Happens When the Gut Immune System Goes Wrong
Interviewer: And your research is also important for understanding diseases like inflammatory bowel disease. Can you explain that part of your research?
Dr. Round: We're very much focused on intestinal immune system development, and diseases like inflammatory bowel disease, they occur in the intestine, and they occur because our immune system fails to tolerate our good microbes. We're chock-full of these microbes within our intestine, and they do, in fact, help to influence our immune system development. But we have a fine relationship with these microbes in our intestines such that they help us, and then in turn we let them live on our bodies so we don't mount immune responses against them. So the research that we do in this lab is to identify what organisms live in our intestine that may prevent the development of inflammatory bowel disease. And we've found that some of these organisms can actually protect from the development of IBD.
The Search for Natural Bacteria-Based Therapies
Interviewer: So your work could possibly lead to new types of therapies?
Dr. Round: That's right. We're hoping to identify what I like to refer to as natural therapeutics. You know, we've had this long evolutionary process with these organisms, and we're highly dependent on these organisms for our development and our health. So we think that we can ultimately identify the organisms that are having the beneficial activity and maybe put them in a pill form or administer them in yogurt. There are many ways. But, we do hope to identify which ones are good, and then give them to people who are sick.
Could Gut Bacteria Influence Autism and Behavior?
Interviewer: Now you said there could be a link between these good bacteria and autism. That's fascinating. Can you talk about that a little bit?
Dr. Round: This is very new research, and there's only a couple labs in the country that I'm aware of that study this. One of them is my former mentor, Sarkis Mazmanian at Caltech. But they are doing behavioral studies with germ-free mice. So these are sterile mice that live in these bubbles that don't have any of these microbes living on their bodies, and they can do behavioral studies and show that mice that don't have commensal microbes are more anxiety-prone. They're not as adventurous. So there's all these behavioral defects, and if you induce an autism-like disease in these mice, they get exacerbated forms of autism. So there are these implications that these bacteria can also influence how we behave and influence diseases such as autism.
Interviewer: That's fascinating. And it's not just behavior. It's obesity and many other processes, too.
Dr. Round: That's right.
Taking Care of Your Good Bacteria Starts Early
Interviewer: And so the take-home message we think is that we need to take care of these good bacteria. How can you and I do that?
Dr. Round: The biggest thing is to not overdo it with antibiotics. So this is especially important in young children. So there is a direct correlation with the number of times that a young child has taken antibiotics and the development of IBD later in life. So the more times a young child takes antibiotics, the more predisposed they're to developing autoimmune diseases like inflammatory bowel disease. So if your child gets an earache, don't push the doctor to give you antibiotics. Children's immune systems can clear those types of infections. Other things that people can do is to eat their yogurts and stay clean. But don't overdo it with the sanitary alcohol cleansers.
updated: April 10, 2025
originally published: November 21, 2013