Professor Tim Spector: I was wrong about Vitamin D & sunlight! The 7 health habits he's changed his mind about

**Jonathan** (0:00)
Welcome to ZOE Science and Nutrition, where world leading scientists explain how their research can improve your health.
Health advice never stands still. One year, we cut fat. The next, we fear sugar. We demonize seed oils, and then we defend them. The headlines move quickly, but inside the body, change unfolds slowly. Arteries clog over decades. Risk accumulates long before symptoms appear. Professor Tim Spector, one of the world's most cited scientists, has spent years studying how food and lifestyle shape these invisible processes. He challenged calorie counting when everyone else believed in it. He warned about ultra-processed food, while many nutrition scientists deny that there was even such a thing. And of course, he has led the world in understanding the central role of the microbiome in our health. But science does not freeze in time. New trials emerge, larger datasets appear. Evidence deepens, or sometimes it reverses. This year, Tim has been examining his own health closely. He's reviewing new research. He's looking at his own test results. Today, Tim explains where he has changed his mind, where he hasn't, and how he decides when new evidence is strong enough to act on. He shares the seven new habits that he started in 2026, from supplements and new exercises, to sleep and oral health, and the reasoning behind each one. Because the challenge isn't keeping up with every new health claim on social media. It's knowing which ones deserve your attention, and which ones you can safely ignore. By the end of this episode, you won't just have heard the changes that one of the world's top scientists have made in his life. You'll understand how to navigate shifting advice for yourself. Tim, thank you for joining me today.

**Tim Spector** (1:53)
Great to be here.

**Jonathan** (1:55)
I don't really need to tell you the drill. We have a set of Q&A questions. The good news is you don't know what they are, but I do.

**Tim Spector** (2:02)
Okay, far away.

**Jonathan** (2:04)
If I brush my teeth badly, could this impact my brain health? Definitely. Have you changed the way that you exercise this year?

**Tim Spector** (2:13)
I have a little bit, yes.

**Jonathan** (2:15)
Is folic acid only important for women?

**Tim Spector** (2:19)
No, as I recently discovered.

**Jonathan** (2:22)
Is it true that you now have rippling biceps thanks to your new workout routine?

**Tim Spector** (2:27)
You can see for yourself, Jonathan. Yeah, I mean, you know, I've added at least 1% to my muscle mass.

**Jonathan** (2:35)
All right. And then finally, what developing area of science are you most excited about in 2026?

**Tim Spector** (2:42)
I'm really into the brain and the gut-brain connection. I just think it's absolutely fascinating. And a lot of that has come out of the ZOE studies that have pointed in that direction, areas we didn't think about when we started ZOE.

**Jonathan** (2:58)
I'd like to start before we get into the specific things that you've changed in the last year. Maybe step back a little bit and say, what is it about nutrition science that means that we don't just know all the answers? Because I think I was generally brought up to believe, well, science has figured all this stuff out. And I certainly was under the impression 40 years ago that the government knew exactly what we should eat.

**Tim Spector** (3:27)
There's a certain naivety about public perception of these things. In a way, because governments are forced to have guidelines. And guidelines tend to be very black and white. And there isn't really room for nuance when people are giving out a leaflet or something. And so this then leads to a mentality that we have to follow the guidelines and that the guidelines must be correct. Otherwise, all our foundations are going to crumble. And that's why we've taken so long to get to this point, to realize that most of the guidelines were wrong, and that actually the science has changed.

**Jonathan** (4:02)
And can you give an example of where scientific opinion has changed in a big way in your lifetime?

**Tim Spector** (4:09)
In the nutrition space, I was brought up to think that fat was really bad for you. As a junior doctor, I was telling my patients, avoid fats, have starchy foods, things like rice, pasta, potatoes, they're the stuff to have, that's really good for you. And they were, of course, in the guidelines. Nobody really questioned them, just kept saying it. And no research was done to prove the opposite. And it took ages until this has been reversed. And now most countries, although this country is lagging behind in the UK, but even in the US, they've now switched the concept of fat being bad to saying, actually, many fats are good for you. So that's probably the classic one where we've made a 180-degree switch just in a few years, although it seems to have taken much longer than it should have done.