Professor Tim Spector

That's essentially what epidemiology is.

And what these studies have shown is that if you follow susceptible people and find out who at the end ended up with Parkinson's disease, you will see that about 90% of people who end up with Parkinson's disease had some gut problems 10 years before.

And you might say, okay, well, might not be related, might be two separate things, but they've actually...

found the same protein changes in the brains in people with Parkinson's disease, this particular protein that gets misfolded.

It's a bit equivalent to Alzheimer's, but it's a separate type of protein, alpha-synuclein, and it gets folded and you get this characteristic thing you can see post-mortem called a Lewy body.

But it's the protein folding that's important.

And if you look in the gut, not only do these people have constipation and bloating from 10 years before, really sluggish intestine, but they have the same proteins

that are misfolded that you can find in their gut.

And they think that it takes 10 years for these proteins to go slowly up the vagus nerve into the brain and then it causes the problem there.

So this is the latest theory behind Parkinson's disease that it actually starts in the gut and it's related to inflammation in the gut.

So these proteins start folding when the gut is not happy.

which means that you could potentially prevent Parkinson's disease by a gut-friendly diet.

It looks like the evidence is building that that's going to be pretty concrete soon.

If that's true, then you may think, what other diseases might have that origin there that we really don't understand?

What about multiple sclerosis that might happen there first?

And it really starts to bring...

You know, this obscure of these brain disease back into the domain of the rest of the body and what's going on there and these metabolic problems.

Diabetes is the number one risk factor for so many of these conditions as well.

So if you've got type 2 diabetes, you're like four times as likely to have a brain disease.

Not only depression, but also bipolar, schizophrenia, epilepsy, all of these ones.