Here is the full transcript and summary of Robin Shields-Cutler’s talk titled “What I’ve Learned From My 3 Trillion Closest Friends” at TEDxGrinnellCollege conference.
In this TEDx talk, microbiologist Robin Shields-Cutler discusses the microbiome, an ecosystem made up of hundreds or thousands of different species of microbial organisms that exists in each and every one of our guts. He emphasizes that scientists were able to study the microbiome using advances in microscopy and DNA sequencing technology and explains its importance in shaping our physiology, training our immune system, communicating with our brains, and helping us digest food.
Listen to the audio version here:
TRANSCRIPT:
I’d like you to think about your friends. What do your friends do that supports you? How do your friends affect the way that you feel and think? If you feed your friends, do they feed you?
How many of these close friends do you have? Now, I don’t mean to brag, but I have about three trillion, give or take 10 or 20. But by the end of this talk, I hopefully will convince you that you do, too. A little bit of a warning, though.
Every time you, or sometimes when you go to the bathroom, you might lose a couple hundred billion of these friends. I’m not talking about people, as you probably figured out. That’d be weird. I’m talking about one of the most complex ecosystems on our planet.
And it exists in each and every one of our guts. This is an ecosystem made up of hundreds or thousands of different species of microbial organisms we call the microbiome. And if you were to count all these cells, it would equal or exceed the number of human cells in your body. You could pull this mass of writhing, squishy cells out, could weigh as much as a pound.
So that’s kind of a lot. But a trillion is a hard number to really figure out. I bet a lot of you can’t really conceptualize what a trillion means. It’s on the order of the US national debt, but I’m going to guess that’s not really helpful either.
But you probably have a good idea of what a second is, how long a second is. I’m a professor. I’m very aware of people counting the seconds, usually until I’m done talking. You have an idea of what a second is. If you add three zeros to that, you get 1,000 seconds. 1,000 seconds before noon today was 11:53 AM. If you add three more zeros, you get a million seconds. And a million seconds ago was about 12 days.
Add three more zeros, and we get a billion seconds. A billion seconds ago, I was about 5 and 1⁄2 years old. I’ll let you do the math later on that. But if you add another three zeros, we get to a trillion.
And a trillion seconds ago, the year was 29,687 BCE. Prehistoric humans hadn’t even made it to the part of the world that we live in today. So now you might be saying, OK, scientist person, how are you going to study something that’s so immense and you can’t even see it? So I’m going to start by taking us back about 11 billion seconds.
That’s the late 1600s. And a curious Dutch haberdasher by the name of Antonie van Leeuwenhoek. And he made these glass lenses that allowed him to magnify what he was looking at, first microscopes. He peered into things like dirty pond water and saw a microbial world that had never been witnessed before.
Since the turn of the last century, an analogous revolution has been taking place and a shift in perspective. This is mostly driven by advances in DNA sequencing technology. So now our very expensive, fancy, modern glass lenses can allow us to peer into the microbiome, ask questions about what species are present, what genes are they carrying, what those might do, and how is it changing?
Now, very much like in the 17th century, our version of van Leeuwenhoek’s revolution is changing the way that we look at science and the way that we look at microbial communities. This has led to an avalanche of new knowledge and an equal number of questions about the role of these microorganisms.
And I hope it’s beginning to chip away at the notion that all bacteria are bad germs. In contrast, these microorganisms are truly essential for our well-being. From the moment we’re born, we’re colonized by bacteria and fungi, and these microorganisms help shape our physiology. They train our immune system. They communicate with our brain. And they help us digest our food, giving us essential nutrients and vitamins that we can’t process otherwise. You feed your friends, and they’ll feed you.
If you raise a mouse to be completely sterile, no bacteria enter on its body. You can do this in the lab. These animals will survive, but they need about a third more calories in order to maintain their weight, like their dirty, bacterial-laden cousins. They’re also susceptible to a lot of illnesses and infections.
To quote Joni Mitchell, you don’t know what you’ve got till it’s gone. So back in 1957, a medical technologist and a curious physician on the East Coast noticed that a lot of surgical patients experienced really horrible GI symptoms after going home. Now, they also noticed that the bacteria normally present in these people’s feces was basically absent. Strange.
These patients, nothing about the surgery had to do with their intestines, but they had received high doses of antibiotics in order to prevent an infection. So they noticed this, and they decided to do a little experiment. They collected feces from these patients before they went in for surgery, before their antibiotics. And then afterward, they fed it back to them in capsules.
This anecdotally worked pretty well at preventing these people’s GI symptoms after the surgery, until the hospital administrators found out and nearly fired them. But this technologist, his name was Stanley Falkow, and he went on to be one of the most respected, successful researchers in modern microbiology.
So you feed your friends, they’ll feed you and maybe feed somebody in need.
So I’m telling you that you have this incredible microbial ecosystem in your bodies. You may have spent a lot of your life totally unaware of this. How do we protect it? What can we do? What kind of things influence this?
So as a way of starting to explore this, I’m going to tell you one more story. This story is called A Tale of Two Tamarins. The story begins with two individuals in different corners of the country that are coming to the Midwest. They’re going to live together, share a room, eat a similar diet, spend a lot of time together with similar other individuals in a small space.
To ensure their adequate nutrition, they’ll be provided with access to lots of fruits and vegetables and a really special formulation of mealworms. Meet Cliff and Weasley. Who did you think I was talking about? So we measured the microbiome.
This project was led by an undergraduate researcher in my lab. We measured the microbiome of these tamarins throughout their journey to the Midwest through stages of quarantine and a very gradual, intentional set of introductions to one another until they were spending time together and sharing space and living together.
Now, you might not be surprised that the microbiomes of these two individuals were pretty dissimilar to start. They were coming from very different places. So in this chart, the dots, each point represents the microbial community of a given monkey on a given day. And points that are close together represent communities that are more similar.
The further apart two points on the chart, the more dissimilar those two microbial communities are by composition. And so what we saw over time was as these two individuals went through and spent more time at the same zoo, were eating more similar diets, spending time together, over time, their microbiomes converge to an intermediate very similar to one another.
So as they became more close, so did their microbiomes, their microbial communities. You feed your friends, and they’ll feed you, and maybe even your friends and family. We have a lot yet to learn about what’s going on here. We only know what’s driving this and what consequences, if any, there are on individuals for changes like these.
But it starts to show us how things in our environment, people that we spend time with, things we eat, how these things can influence and change the composition of microbes in our gut. Now, unfortunately, trends toward more processed diets, overuse of antibiotics, and just relentless sanitizing of every surface and material within sight has led to a gradual but important and alarming loss of biodiversity in a lot of these microbial communities.
And as we threaten the diversity of these communities, we also threaten their ability to support our health. So what do we do about this? Well, everybody’s microbial community, everybody’s microbiome is unique. There’s not one therapy or recommendation that’ll work for everybody. And truthfully, the field of the microbiome, the human microbiome, other environments, is really in its infancy. But the evidence that we have so far supports the idea that rich biodiversity in these communities might help support our overall health.
How do we go about doing that? Eat a lot of different foods, minimally processed, that provide a nice, diverse source of dietary fibers. Try some fermented foods, a lot of which have a bounty of helpful bacteria as well. And the key bacteria, many of the key bacteria in your guts, thrive on these dietary fibers.
They can digest them and then feed our bodies and help regulate our health. I think above all else, be curious about the things that we don’t understand and the things that we can’t see. Be a good listener. Listen to your friends, including your microbial ones.
Microbes affect us and our world in ways that we are really only beginning to understand. If we feed and nurture our friends, they’ll feed and nurture us. Thank you.
SUMMARY OF THIS TALK:
Robin Shields-Cutler’s talk, “What I’ve Learned From My 3 Trillion Closest Friends,” offers insightful perspectives on the human microbiome. Here are the key takeaways from his talk in a summarized form:
Magnitude of the Microbiome: Shields-Cutler begins by intriguing the audience with the notion that each person has about three trillion microbial friends in their gut, a number exceeding the human cells in our body. He uses relatable analogies to help conceptualize the enormity of this number.
Historical Context: He delves into the history of microbiology, highlighting the pioneering work of Antonie van Leeuwenhoek in the 1600s who first observed microbial life. Shields-Cutler connects this to the modern revolution in microbiology, driven by advancements in DNA sequencing technology, allowing us to study the microbiome in detail.
Essential Role of Microbes: The talk emphasizes that not all bacteria are harmful. Instead, these microbes are crucial for our well-being, shaping our physiology, training our immune system, aiding in digestion, and providing essential nutrients.
Real-Life Examples: Shields-Cutler cites examples to illustrate the microbiome’s importance. For instance, he mentions mice raised in sterile environments requiring more calories and being more susceptible to illnesses, highlighting the role microbes play in normal physiological functions.
Antibiotics and Microbiome: He discusses an incident from 1957 where patients suffered GI symptoms post-surgery due to antibiotic-induced changes in their gut bacteria. This anecdote underscores the delicate balance of our microbiome and the impact of antibiotics.
Influence of Environment on Microbiome: Through the story of two tamarins (monkeys) with initially different microbiomes, he shows how environmental factors like diet and social interactions can align their microbial communities. This story illustrates the microbiome’s adaptability and responsiveness to external factors.
Modern Challenges to Microbiome Health: Shields-Cutler points out that processed diets, overuse of antibiotics, and excessive sanitization are reducing microbial biodiversity, which could have negative health implications.
Personalized Microbiome Care: He notes that everyone’s microbiome is unique, and there’s no one-size-fits-all solution for maintaining a healthy microbiome. However, he suggests a diet rich in diverse, minimally processed foods and dietary fibers can promote a healthy microbiome.
Curiosity and Understanding: Finally, Shields-Cutler encourages curiosity about the unseen and not fully understood aspects of our world, including the microbiome. He emphasizes the mutual relationship we have with our microbial friends and the need to nurture this relationship for better health.
Overall, Shields-Cutler’s talk underscores the critical role of the microbiome in human health and the need for a deeper understanding and care of this vast microbial ecosystem within us.