Diabetes and dementia

Is there a connection between diabetes and dementia? What do they have in common? Does having diabetes increase your risk of dementia? Get all the answers on this page.

Senior cyclist eating a banana.

What is diabetes?

Diabetes occurs when the body is unable to make enough insulin or use the insulin it makes properly.

  • Insulin is a hormone used by the body to control glucose levels, or the amount of sugar, in your blood.
  • Glucose is one of the main sources of fuel for the body, providing energy the body needs to perform all necessary functions.

Types of diabetes

There are two main types of diabetes – type 1 and type 2. A third type, gestational diabetes, occurs temporarily during pregnancy.

What do diabetes and dementia have in common?

Studies have shown that type 2 diabetes can be a risk factor for Alzheimer’s diseasevascular dementia and other types of dementia.

This is because the same cardiovascular problems that increase the risk of type 2 diabetes also increase the risk dementia. These include:

  • Obesity,
  • Heart disease or family history of heart disease,
  • Impaired blood vessels,
  • Circulation problems,
  • High cholesterol, and
  • High blood pressure.

Research has also proved that, similar to diabetes, glucose is not used properly in the brains of people with Alzheimer’s disease. This may be caused by nerve cell death, which reduces the brain’s ability to interpret messages. In the case of vascular dementia, brain cells die due to lack of oxygen, preventing brain cells from communicating with each other.

Beta amyloid plaques, which build up in the brains of people with Alzheimer’s disease, have also been shown to prevent insulin receptors in the brain from doing their job. This can impact insulin production and cause brain cells to become insensitive to insulin.

Learn more about the risk factors for dementia.

Reducing your risk for diabetes and dementia

What’s good for your heart is good for your brain. Living a healthy lifestyle that promotes cardiovascular health will benefit your brain.

  • Eat a healthy diet rich in vitamin D, folate, and B6 and B12 vitamins,
  • Exercise regularly – both your body and mind,
  • Stay socially active and challenge yourself daily, and
  • Protect your head when playing sports.

Get some brain-healthy tips to reduce your risk of dementia.

Is Alzheimer’s disease actually “type 3 diabetes”?

Recent studies suggest that the brains of people living with Alzheimer’s disease are in a diabetic state, partly due to the decrease in or insensitivity to insulin.

There are many similarities in the brains of people living with diabetes and the brains of people living with Alzheimer’s disease; however, diabetes only remains a risk factor. Some people with diabetes may go on to develop dementia, but many will not.

More information and resources

Risk factors. Alzheimer Society of Canada, 2018. Read about risk factors for dementia in our downloadable, print-friendly infosheet. This sheet also contains strategies and lifestyle changes that can help you reduce your risk of developing dementia.

Heads up for healthier brains. Alzheimer Society of Canada, 2015. Are you wondering what you can do to keep your brain healthy and reduce your risk of dementia? This handy, downloadable brochure tells you everything you need to know about the relationship between brain health and dementia.

Diabetes Canada. Canada's foremost charitable organization that provides more information on diabetes, supports people living with diabetes and is committed to advancing research that will end diabetes.