Did you know that you're not just one living thing? No, you're actually an entire ecosystem of teeny tiny, creepy crawly, living microbes. They're all over -- from your skin to gut to even your sex organs. Oh my.
What role do these microbes play in our bodies? How do they affect us, and how can we make the most of them? I reached out to Dr. Justin Sonnenburg, assistant professor of microbiology and immunology at Stanford University School of Medicine, to find out. Click on the video above to hear the amazing things he told me (full transcript below). Talk nerdy to me!
JACQUELINE HOWARD: Hey everyone. Jacqueline Howard here. Take a look in the mirror. What do you see? You may say an individual -- a man or a woman -- but in reality, you’re an entire ecosystem. That’s right. You're made up of trillions of cells--some human, of course, but also lots of bacteria. In fact, those bacterial cells outnumber your own human cells 10-to-1. So, we’re more microbial than we are human. Eek! But seriously, these microbes affect us in profound ways. Just take it from Dr. Justin Sonnenburg. He's a microbiologist at Stanford University’s School of Medicine.
DR. JUSTIN SONNENBURG: These microbes have become really integrated into our biology. There are developmental cues that we rely on from these microbes; they help us digest food; they help shape our immune system; alter our metabolism; and there’s even some emerging evidence that they can influence our nervous system, so influence things like moods and behavior.
JH: That’s crazy. Germs control your mood!? But, yeah. It turns out bacteria teeming in your gut just may influence your mind. Have you ever had a gut feeling? Research shows that gut germs produce hundreds of neurochemicals that your brain uses to regulate not just mood but also things like learning and memory. For instance, these microbes manufacture around 95 percent of your body’s serotonin. That’s the neurotransmitter that’s linked to positive emotions. These microbes in your body are collectively called your human microbiota. So, how do we get colonized in the first place? As we all know, the environment is full of germs, some good some not so good. But things get started way, way back.
JS: When we’re in the womb, we’re actually sterile. We have no microbes associated with our bodies. And then once we’re delivered, we represent an open ecosystem for these microbes and they rapidly colonize our body. We know for instance the babies that are born by caesarean section, their microbiota for the first days of life look very much like their mother’s skin, whereas babies that are born vaginally, their microbiota look like their mother’s vaginal microbiota.
JH: That’s not all. Breast feeding is another way a mother helps in the assembly of a young microbiota. Her body produces sugars to help feed beneficial gut bacteria and keep the baby healthy. As we grow older, we continue to encounter microbes in the foods we eat as well as our environment. Our individual microbiota become as personal as a fingerprint. It’s unique to who we are biologically, where we live, and who we’ve been in contact with.
JS: The gut microbiota is incredibly individualized. Each one of us has a different human genome but we differ even more substantially in the content of our microbiome.
JH: Now, what would happen if we got rid of those trillions of microbes in our bodies? Would we weigh less? Yeah, but not by that much. According to Dr. Sonnenburg’s back-of-the-envelope calculation, we’d lose only around a fifth of a pound because these microbes are so tiny. Strangely, without our microbiota, we may smell different -- maybe even smell better. But, we would also look and feel not too good. Bad germs would have free reign to colonize our bodies and wreak havoc. So, how may we maintain a healthy microbiota? Dr. Sonnenburg said more support for research in this regard is needed -- as well as in the field of microbiology as a whole -- but he still offered some tips nonetheless.
JS: Eating a diet that’s rich in different sorts of plant material, that’s rich in dietary fiber, is I think now generally believed to be a really good way to nurture a healthy microbiota. Adding foods like yogurt, kimchi, and sauerkraut to your diet can be a nice way to add beneficial bacteria.
JH: One more tip he mentioned is to minimize antibiotic use to when it’s absolutely necessary. That's because when you take antibiotics, not only does the bad microbe in your body take a hit but also your good microbes. So there’s some collateral damage. But what do you think of now seeing yourself as an island of sorts where a bunch of living things have colonized to form a dense ecosystem? Leave your thoughts in the comments. You know how we do, talk nerdy to me!
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