5 ways relationships change your gut health | Prof Tim Spector

**Jonathan** (0:00)
Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health.
Strep throat, food poisoning, pneumonia. All examples of nasty microbes that spread easily from person to person. But not all bacteria that spread between people are bad. Some can actually transfer health benefits. Good microbes that live in our guts, skin, and elsewhere can also be transferred from other people and the environment around us. So how can healthy gut microbes be transmitted? What are the potential benefits? Is a healthy gut microbiome contagious? Today, I'm joined by Professor Tim Spector, a leading expert on the gut microbiome, one of the world's top 100 most cited scientists, and my scientific co-founder here at ZOE. In this episode, Tim will help us answer these questions and explain how to maximize the benefits of sharing good microbes with friends and family. Tim, thank you for joining me today.

**Tim Spector** (1:10)
A pleasure as always, Jonathan.

**Jonathan** (1:12)
So you know the rule. We're going to kick off with a rapid fire Q&A from our listeners. You ready to go? Ready. Do most bacteria cause disease?

**Tim Spector** (1:22)
No.

**Jonathan** (1:23)
Are we born with a fully formed gut microbiome?

**Tim Spector** (1:27)
Nope.

**Jonathan** (1:28)
Is our gut microbiome influenced by who we live with?

**Tim Spector** (1:32)
It is.

**Jonathan** (1:34)
Is having a pet good for our gut microbiome?

**Tim Spector** (1:37)
Usually, yes.

**Jonathan** (1:39)
If we spend time with someone with anxiety, could their gut bugs make us more anxious?

**Tim Spector** (1:46)
It could, Jonathan.

**Jonathan** (1:48)
Can bacteria from soil benefit our health?

**Tim Spector** (1:52)
Sometimes.

**Jonathan** (1:54)
And finally, what's the most surprising new thing that you've learned about gut bacteria?

**Tim Spector** (2:01)
Well, I've known for a while how important it is for our metabolism and our immune system. But what's really struck me is the latest research showing how important it is for our brain and our mental health. I think that's really striking. And I think this is where we're going to be seeing some dramatic developments in the next few years.

**Jonathan** (2:21)
That sounds incredibly exciting. And actually, I'm looking forward to this whole podcast, because obviously we talk a lot about the bacteria that live in our guts and things like eating 30 plants and more fiber, and also the way that our sleep and stress, all of these things can affect us. But we're talking about something different today, which is really exciting. So instead of focusing on the bacteria that are already inside us, we're going to talk about how those bacteria get there in the first place. And I hope at the end a bit about how we might be able to get some more of the good ones. So Tim, when does our gut microbiome, this collection of bacteria, start?

**Tim Spector** (2:59)
Well, since humans evolved, we've basically been passing on our microbes from one generation to another, as the basic core building block set. So it comes from our mothers. So when we're in the womb, essentially for all intents and purposes, we're sterile in terms of microbes.
And it's the birthing process that is so messy and dirty, and our mouth is designed to be in the right place through the birth canal, that it's getting the microbes from the birth canal and the intestine, so that our mouth as we're coming out is getting full of microbes. And in the next few hours, they develop and give us our building blocks for what then carries on. So it allows the child to have sufficient microbes that they can break down breast milk and survive. And then it uses that base to slowly build up for the next few years. But it takes really about four years until we have a proper functioning gut microbiome that resembles the adult form.

**Jonathan** (4:09)
And so when a fetus is in the womb, there are no microbes inside its gut, it's empty. And then, is it just by chance what you're describing? That like they pick up some microbes as they're being born, but equally well, they could pick them up over the following few weeks, or is there something more controlled about this?

**Tim Spector** (4:29)
It's controlled by evolution. Essentially, we've had millions of years that all mammals go through this birth process and it's been designed as a way of transmitting the microbes from one generation to another into the gut of the newborn. And so, it's not by chance. This is basic natural selection. That's why the birthing process has been developed in this way, that as well as trying to ensure survival at the same time, it is a way of the mother passing on the microbes. And there are changes in the later stage of pregnancy in women, both in the vagina and in the gut microbiome, where those microbes are changing specifically so they can be passed on to the child.