The gut-brain axis

AMY LOUGHMAN: So when it comes to the gut-brain axis, and the gut microbiota is a really important part of that. It’s just like any part of the human body functioning. The body needs to learn how to do it little by little, and then comes to a mature state as we see in humans. So by about three, we think the gut microbiota looks a lot like it does in adults by age three. And we know that there are many environmental inputs that impact on how the microbiome develops. It starts as soon as a child is born, from the way they’re born and the kinds of environmental exposures they’re exposed to.

This quickly changes in response to feeding mode, any medications they need to receive, and then their physical surrounding environment. Importantly though, it also includes their emotional environment, how psychologically safe or the kind of care that a child receives.

So when it comes to staying healthy with your brain in older age, we know that it’s important to maintain a variety of lifestyle factors to support the brain. That includes diet, as we’ve just spoken about in this course, physical activity, social interaction, and also things that stimulate the brain and are of interest to the person. And those things are important to the gut microbiome as well as to the brain. We think that might be part of why it’s so important for the ageing brain. So studies are beginning to show how, in Alzheimer’s disease, the gut microbiota is different. And the same factors that impact the gut microbiome impact someone’s risk of developing a neurodegenerative disease such as Alzheimer’s disease.

I think something many of us would like to know is, what is the perfect gut microbiota? Or how can I optimise my gut to best support my brain and my physical health? And it’s a really tricky question to answer. We know that for people with certain kinds of diseases, for example, diabetes or rheumatoid arthritis or inflammatory bowel disease, their gut microbiota diversity, the number and type of bacteria in their gut is different to that of people without the diseases. But beyond, that the results of different studies really vary from one study to another. So it’s tricky to say exactly what kind of bacteria you might like in your gut. And of course, it changes across the lifespan as well.

One simple answer, though, we think so far is that eating a wide and diverse range of foods will help support a gut microbiota to be diverse and to be able to do all of the kinds of functions that a gut microbiota does to support the body and the brain.