The latest Alzheimer's research

What does the science say?
09 July 2019

Interview with 

Katy Stubbs, Alzheimer's Research UK


Brain cartoon


Even in the scientific world, Alzheimer’s can be a complex issue. Just in the last couple of months, there have been papers saying the route cause of Alzheimer’s is as diverse as high cholesterol, to gut microbes and even herpes virus. But can all, or any, of these things be true? And what’s worth picking out from things like this? Chris Smith was joined in studio by Katy Stubbs from Alzheimer’s Research UK...

Katy: It is yeah. And unfortunately we can't turn back the clock on that and because we're living longer we experience so much across our lifetimes and this combined with our genes is really what is going to be driving the risk of Alzheimer's disease.

Chris: Is it fair to say then that it's a multifactorial thing, it's not just one trigger for the majority of people. The minute number of people who have a defined genetic cause aside, for most of us it's going to be the excesses of life including living too long which ends up causing this.

Katy: Indeed you're exactly right. So that's what's really hard for us is trying to pinpoint what are the most important things that we could maybe change. So in terms of lifestyle factors trying to understand where we can give people advice to reduce their risk.

Chris: Is that where the claim about high cholesterol comes in?

Katy: Yes. So that the message really is what's good for your heart is good for your head. Your brain is only about 2 percent your body weight but needs about 20 percent of your blood supply. It’s a hungry organ. And so if the blood vessels in the brain aren't kind of in tiptop condition if they're not providing those nutrients and the oxygen to your brain cells then those cells aren't able to do their job as well. And so the thing with cholesterol is it's essential for all the cellular processes that we have but too much of it is damaging. So it clogs up our arteries and if this happens in the brain, then this is going to cause damage within the brain.

Chris: And the link to gut microbes because the microbiome is on everything these days not a week goes by without some new paper alleging that the microbes that live on us and in us are changing our lives and all kinds of manifold ways we haven't previously anticipated.
Katy: Yes, our guts are full of bacteria and they do important things in helping us digest our food and get all the nutrients out of our food. But actually what’s emerging from the science is that it's the variety of your microbiome and the levels of that variety as well so the kind of the profile that you have and we're not at the stage where we know what a healthy one looks like and what one from someone with Alzheimer’s looks like. So we are just at that early stage of trying to see the key differences. And so we don't know whether the changes in the variety of your bacteria are they driving the disease process or are they happening at the same time and are just kind of a consequence of what's happening? We need to understand that. So we don't yet know what is shifting those changes. Is it things in people's diet. Is it their genes that can affect the bacteria you have in your stomach so there's so many other things which I understand and we're still at those very early stages with understanding it.

Chris: What about genetics though, because we've alluded to this a bit and we know that there are rare examples of almost every disease on Earth where genes plays a huge role but on average does genetics play a role in Alzheimer's?

Katy: So there is some role for it and it's really important to understand the different types, the different ways in which genes can affect our disease risk. So Claire's already mentioned genes that can cause disease and for Alzheimer’s that’s incredibly rare.

What we're mainly talking about is risk genes. So genes that if you have a change in them they might increase your risk maybe 5 percent but for most genes it's more like 1 or 2 percent they might be shifting your risk so it's across the whole of your genetic code. All those different changes could put you in a high risk category compared to somebody else. And we've discovered about 30 genes that can affect your risk of Alzheimer’s at this point but the likelihood is it could be in the hundreds and the thousands. So we need to again understand that profile of change and see what makes somebody high risk versus low risk.

Chris: Have you found genes, because it's easy to obsess about problems that we do get. Have you found anybody who has certain genes that seem to protect them from Alzheimer's disease. Because arguably they'd be the ones to look at to find out why.

Katy: There is a lot of interest in a group of people that are often called super agers so people who reach their 90s or over 100 and they don't seem to have any kind of ill effects of it with their health. And if we're trying to understand why are those people are doing so well, that could offer up some clues as to what's going on with their genes and is it protecting them because it's more likely that than their lifestyle.

Chris: What's the take home message with Alzheimer's then what should a person listening to this take away as the best way to run their life course to reduce their risk to the minimum it can be?

Katy: So it’s that message of what's good for your heart is good for your head so healthy balanced diet.The Mediterranean diet has the best amount of evidence behind it so lots of lean meat so fish and poultry and nuts and oils and lots of fresh fruit and vegetables for the diet really.

Chris: Is exercise protective?

Katy: Exercise, it's not protective, it's more that if you're not active your risk is increased. If you're active you're your risk is more normal so keeping physically active, your weight, your cholesterol, your blood pressure... all those things. Keeping socially integrated as well is really important.


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