Skip to 0 minutes and 10 secondsIn this step, I'm with Professor Glenn Gibson in his lab to discuss how he uses models of the human gut to study how the microbes that live there affect our health. So, Glen, one of the principal aspects of this course is how microorganisms fit into the food that we eat and, indeed, how they influence our health and impact our lives. So could you please explain to me a little bit about the human microbiome, how we get it and how we can influence it? Sure. So the microbiome is the collection of microbes associated with the body, and these differ depending on which area of the body we consider.

Skip to 0 minutes and 48 secondsSo the skin isolates are different to those which are in the hair, in the oral cavity, in the mouth, in the nose. But what we do here is actually research the microbiome of the human gut. And so we are very interested, of course, in food and its impact upon the gut microbiome and what we can do to improve health of consumers as a result of this. So how can we actually influence the microbiome in our gut? There's lots of things which influence the microbiome of the gut, many of which we can't control, for instance, stress or rage. These affect the microbiology of the gut. But one thing we can do something about is diet.

Skip to 1 minute and 30 secondsAnd fortunately for us, diet is the main factor which influences the composition of the gut microbiome. And the microbiome, like any mixed microbial community, has positive types in it. It has neutral types and negative types. And what we like to target, of course, through our research is diets, which improve the positive at the expense of the others. And where do we get these microbiomes in the first place? Not very nice to know but they are the first present we actually ever get in our lives because the microbiome is given to us at birth. So right up until the point of being born, we are sterile. But we acquire our gut microbiome during the birth process.

Skip to 2 minutes and 12 secondsAnd it doesn't matter whether we are delivered through the vaginal or caesarean route, it happens there and then. Now bacteria can grow pretty much anywhere. They can grow in volcanoes. They can grow in deserts, very dry areas. They can grow in the presence of irradiation. Enormous heat isn't a problem to them. So the human body is a very, very favourable environment for their growth indeed. So it only takes a few cells during the birth process to get into the gut. And what do they find there? They find a very warm, nutritious environment, and they stay there for the rest of our lives, and they grow up to very enormous levels indeed.

Skip to 2 minutes and 50 secondsAnd humans, if you like, are the ultimate hotel because we feed our microbiome, our gut microbiome, three times per day on average, as easily as we feed ourselves. And so we have all of these trillions and trillions of bacteria with us. Most of them, in terms of the gut, are in the large intestine, which is at the end of the GI tract. There are species also present in the small intestine and stomach, but the colon is the main site of what we are interested in. And in that organ, there are probably far more microbial cells than there are human cells in the rest of the body.

Skip to 3 minutes and 25 secondsAnd I think the estimate is about 90% of the cells associated with humans exist as bacteria in the large intestine. And there's differences between our small intestine and our large intestine? Yes, well, when we eat something, it's in our stomach for about 1/2 to one hour. It's in our small intestine for about three or four hours and in our large intestine for about two days on average. And so basically, the bacterial numbers reflect this. And the numbers are very low in the stomach. It's acidic. Transit time is quick. They get a bit higher in the small intestine where transit time goes up two hours.

Skip to 4 minutes and 3 secondsBut the highest in the large intestine because things move very, very slowly through the large intestine. The pH is more favourable. And that's why most of the microorganisms in the body are in this organ. Wow. So judging from the pungent odour in this room, how do we actually study microbiota? It's certainly the smelliest lab in Reading and possibly one of the smelliest labs in the whole country. And that's because we have an array of models of the gut behind us bubbling and gurgling away. And this is what we use for our research. And so the models reflect the large intestine so they are gradients of pH, substrate concentration, bacterial growth rate, which reflect or mimic different areas of the colon.

Skip to 4 minutes and 50 secondsSo the right, transverse, and left side are all mimicked in these models. And the models we set up can reflect infants, adults, young people, elderly people, or particular clinical states that we may be interested in, for instance, ulcerative colitis, Crohn's disease, irritable bowel syndrome. And what we do with the models is test interventions to stimulate the beneficial bugs in each of these situations. And if we are happy with the results of that, we then move to human studies and test in-vivo. So if I wanted to actually improve my own gut microbiota, how would I go about doing that? Well, there's two options, probiotics and prebiotics. And Gemma, my colleague, is going to explain the ins and outs of these subsequently.

Skip to 5 minutes and 36 secondsFantastic, looking forward to speaking to her about that. Sure, good. Great. Thank you.

Meet Professor Glenn Gibson

In the previous Step you quantified the number of aerobic bacteria in a sample of food to determine if it was safe to eat. In this Step, I meet with Professor Glenn Gibson to discuss how he has developed experimental glass models of the human gut to research the effects of diet on the human microbiome and how gut microbes affect our health.

If you’d like to find out more about the gut model and see it in action, watch this video from another University of Reading online course, A History of Royal Food and Feasting. In this film, Glenn’s students describe how they investigated what Henry VIII’s gut microbiota may have looked like if he had eaten a “meat-heavy” diet and how this may have impacted on his health.

Having watched this discussion with Glenn, what benefits do you think there are from using gut models to test hypotheses about the effects of diet on the gut microbiome before progressing to human trials? Share your thoughts in the comments area below.


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This video is from the free online course:

Small and Mighty: Introduction to Microbiology

University of Reading