Understanding diabetes and brain health

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By Nathan Choat | Friday 17 November 2023

Our recent Dementia Attitudes Monitor survey found that only 36% of people think it’s possible to reduce their risk of developing dementia. But research shows that up to 40% of dementia cases may be linked to factors we can influence.

One of these factors is diabetes, a condition that affects an estimated 5 million people in the UK. And as November is National Diabetes Month, we thought we’d take a closer look at this link.

But first, what is diabetes?

The basics

Diabetes is a health condition that causes people’s blood sugar levels to become too high. When this happens, it causes symptoms like feeling thirsty all the time, tiredness, and losing weight without trying to. There are two main types:

Type 1 diabetes is an autoimmune disease that tends to develop early in life. It happens when the body can’t produce a hormone called insulin, which helps regulate blood sugar levels. It’s the less common form – about one in 10 people with diabetes in the UK have type 1.

Type 2 is the most common type of diabetes and mostly affects people over 25. It happens when the body doesn’t produce enough insulin, or when the insulin it does produce isn’t working properly. The biggest risk factor is obesity or being overweight, but other factors like ethnicity and family history can also impact a person’s risk of developing it.

How does diabetes affect brain health?

Scientists don’t yet fully understand the link between diabetes and brain health. However, research suggests that there is a strong association between the two.

One example of this comes from the Whitehall II cohort study, which recruited more than 10,000 British civil servants in the 1980s and has tracked their health outcomes over time.

Results from the study, which was published in 2021 and focusses on type 2, show that people who developed type 2 diabetes earlier in life were more likely to also develop dementia later on. The younger they were when they developed type 2 diabetes, the more likely they were to develop dementia.

While more research has been conducted into the link between type 2 diabetes and dementia, evidence suggests that people with type 1 could also be at an increased risk of dementia. In fact, the influential Lancet Commission on Dementia Intervention and Care – which regularly assesses the overall evidence around dementia risk – has identified diabetes as a risk factor in its own right.

What these studies don’t show is exactly how diabetes and dementia are linked. However, we know that diabetes can have a negative impact on people’s heart health, and that people with diabetes are more likely to develop high blood pressure and high cholesterol. These conditions are also linked to an increased dementia risk, even in people without diabetes.

It’s important to point out that, while the link between diabetes and increased dementia risk is supported by a growing number of high-quality studies, there’s been less focus on whether taking steps to prevent or manage diabetes causes this risk to fall.

But experts agree that taking steps to lessen your risk of diabetes, and actively managing the condition if you have it, could be an important way to help protect your brain health.

What can I do?

Although there’s currently no way to prevent type 1 diabetes, some cases of type 2 can be prevented. Many of the activities that are known to help protect your brain health – such as eating healthily and being active – can also help you avoid this type of diabetes.

 

Woman chops vegetables on a board. She is chopping tomatoes, while an onion, a lemon and a potato sit to the side.

 

If you already have either type of diabetes, managing it effectively is also an important way to take care of your brain. As well as eating well and staying active to help keep your blood sugar levels in check, there may be treatments available to help. For example, people living with type 1, and some with type 2, will need to take insulin.

If you have diabetes and would like more information about how to manage it, please speak to your GP.

Our research

There’s still lots that scientists don’t know about the link between diabetes and dementia. However, we’re funding research projects to help improve understanding.

For example, Dr Fiona McLean is investigating how Alzheimer’s risk factors, including diabetes, affect the protective barrier between blood vessels and the brain, known as the blood-brain barrier. This can become leaky in early Alzheimer’s disease, letting in substances that damage brain cells.

Dr McLean’s research suggests that, compared to healthy mice, key genes linked to Alzheimer’s are more active in the blood-brain barrier of mice with features of both obesity and diabetes. This provides vital clues about the link between diabetes and the development of Alzheimer’s disease.

With further research, these changes could identify targets for future treatments.

We’re also funding a study by Prof Bettina Platt and Dr Zara Franklin at the University of Aberdeen, who are investigating the role of a gene called BACE1 in linking Alzheimer’s disease and diabetes. You can find out more about this project on our website.

Check-in with your brain

Looking at all the evidence, it’s likely that doing your best to prevent diabetes, or manage it effectively if you already have it, can help protect your brain health. But there are also plenty of other things you can do to keep your brain healthy.

Take the Think Brain Health Check-in today to explore your brain healthy habits and find tips on how to give back to your brain.

If you’d like to find out more about diabetes, please speak to your GP or visit the Diabetes UK website.

 

 

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About the author

Nathan Choat

Communications Officer – Campaigns & Projects