Diabetes and the risk of dementia

Reducing your risk of diabetes

As you get older, you are more likely to develop certain health conditions, including diabetes. To manage this, speak to your GP about going for a health check.

Eating a healthy, balanced diet may reduce your risk of type 2 diabetes. No single ingredient, nutrient or food can improve health by itself. Instead, eating a range of different foods in the right proportions is what makes a difference. This is known as a ‘balanced’ diet.

By eating a balanced diet you are more likely to get all the nutrients you need to stay healthy. The NHS Eatwell guide shows what food groups make up a balanced diet and roughly how much of each is needed to stay healthy.

Research into diabetes and dementia

People with diabetes are at an increased risk of developing dementia compared to those without diabetes. This was from a review that brought together the findings from 14 studies.

Studies also suggest that the risk of dementia increases with longer durations of diabetes. It has even been suggested that diabetes starting at age 70 or later may not affect dementia risk. However, these studies looked at few older people and didn’t follow them for as long.

Despite these studies, the World Health Organization advises that diabetes later in life may still have a negative effect on brain health and can increase dementia risk.

There are reasons that diabetes may affect dementia risk:

• Diabetes is linked to other dementia risk factors – so someone with diabetes is more likely to have high blood pressure, high cholesterol and obesity.
• Some of the changes that occur in Alzheimer’s disease are similar to those in diabetes. In both, nerve cells in the brain may become resistant to the effect of insulin. This may lead to the build-up of amyloid and tau proteins in the brain. Alzheimer’s disease is sometimes unofficially known as type 3 diabetes.

Does diabetes treatment help dementia risk?

Less is known about the difference in dementia risk between treated and untreated diabetes.

The problem is that people who take more medications and insulin are likely to have more severe diabetes, which itself might affect dementia risk. There are also several different types of medications taken for diabetes. One analysis combined 27 different studies finding that several different diabetes drugs were associated with reduced risk of dementia.

Studies of the diabetes drug metformin have had mixed results. Some studies show people taking metformin for diabetes are less likely to have memory and thinking problems or dementia compared to those on other medicines or those who are untreated. However, other research studies suggest that metformin has no effect.

Other than drug treatment, diabetes can be controlled with weight loss and this may also help manage dementia risk.

Insulin resistance (as occurs in diabetes) can also affect the brain. Drugs are being developed for Alzheimer’s disease that work in a similar way to diabetes drugs that tackle insulin resistance.