What’s the story behind diabetes and dementia? – Manuela Volta
I have always being fascinated by the brain, so I became a neuroscientist and spent many years of my life studying the brain in the lab, to learn more about it. Working at Diabetes UK, I’ve been reading about the overlapping research between diabetes and dementia…
Is there a link between diabetes and dementia?
You might have heard of the term ‘Type 3 diabetes’ and wondered what it means, or picked up on discussions around the potential link between diabetes and dementia. I’ve come across questions like:
- What is Type 3 diabetes?
- Is there a link between diabetes and dementia?
- If yes, what is it?
- Is there a risk of developing dementia if you have diabetes?
These are all important questions, and I’ve done some investigating to see what I could find out!
Diabetes: Type 1, Type 2 and Type 3
First, let me tell you about Type 1 and Type 2 diabetes, and how the term “Type 3 diabetes” came about.
Diabetes develops when the body can’t use glucose as fuel, and there are two main reasons behind this. In Type 1 diabetes, our pancreas doesn’t produce any insulin, or not enough insulin, to help glucose enter our body’s cells (known as insulin deficiency). In Type 2 diabetes, the insulin that is produced doesn’t work properly (known as insulin resistance).
In 2007, Susanne de la Monte and her colleagues, at Brown University in the United States of America, were studying the brains of people with Alzheimer’s disease. They found that the brains showed signs of both insulin deficiency, as seen in Type 1 diabetes, and insulin resistance, as seen in Type 2 diabetes.
They concluded that, because the brains with Alzheimer’s showed signs of both Type 1 and Type 2 diabetes, this could mean that there was a form of diabetes specific to Alzheimer’s. They proposed to call it ‘Type 3 diabetes’.
The name wasn’t really picked up within the research community, but recently researchers and the media have started talking about this idea of Type 3 diabetes or ‘brain diabetes’.
Alzheimer’s disease vs. dementia
The terms dementia and Alzheimer’s disease can be confusing, as it’s not always clear what they mean and whether they’re the same thing.
Dementia is a term used to define a big umbrella of conditions, where people can develop memory loss, but can also find it increasingly difficult to perform many every-day tasks involving thinking, problem solving or language. Dementia happens when the brain becomes damaged, by – for example – a series of strokes. Alzheimer’s disease is the most common cause of dementia.
Are diabetes and dementia linked?
Since the 1980s, many researchers have seen a link between dementia and diabetes (in particular, Type 2 diabetes). They’ve also found that having Type 2 diabetes can increase the risk of developing dementia, but they don’t know why this link exists yet.
Researchers are cautious about saying there is a connection between diabetes and dementia, and believe that more studies are needed to investigate it and clarify which condition comes first.
There are reports of symptoms of Alzheimer’s disease in people with diabetes, but also of people with Alzheimer’s disease showing symptoms of Type 2 diabetes.
Researchers all agree that there are many molecules playing important roles in the development of both conditions. These molecules are involved in the way that our body converts glucose into energy, but also in all the activities within our brains that involve insulin.
Are Diabetes UK funding work in this area?
Diabetes UK is supporting several researchers at the moment, who are investigating what happens to the brain during diabetes.
Professor Annalisa Pastore and her team are studying a process called glycation, where sugar is attached to other molecules in an uncontrollable way. The result is toxic for brain cells, causing damage. This process is often found in the brains of people with diabetes and Alzheimer’s disease. Understanding more about glycation in the brain could help to address the link between diabetes and dementia, and ultimately lead to new therapies for diabetes-related complications and dementia.
Dr Miho Terunuma is studying two key molecules that are thought to play a role in inflammation and nerve damage, both of which are seen in the brains of people with diabetes. This could help identifying drugs that could help to manage these complications.
The “chicken and egg question” isn’t answered yet
As it stands, I share researchers’ concerns around confirming this potential link between diabetes and dementia, and I don’t think we’re ready to use the terms ‘Type 3 diabetes’ or ‘brain diabetes’. There is evidence that diabetes and dementia have connections, but we need more research to understand if one condition may lead to the other, or if they simply share common molecules and processes.
Living a healthy lifestyle
The strongest risk factor for dementia is ageing (which unfortunately, we can’t do anything about!), but there are ways that we can all reduce our risk of developing the condition, whether we have a form of diabetes or not. These include keeping physically and mentally active, enjoying a healthy balanced diet, drinking alcohol in moderation, avoiding smoking, and having a good night’s sleep.
Want to know more?
If you’re interested in reading more about the research behind diabetes and dementia, you could check out this blog post on the Dementia Alliance International’s website.
Dr Manuela Volta used to work as a neuroscientist, before making a big career jump into the charity sector. She has been Research Officer at Diabetes UK for the past two years.
Find out about the latest areas of diabetes research Diabetes UK is supporting.