Whether you’re living with it, or know someone who is, you already know about pre-diabetes, type 1, and type 2 diabetes. But is Alzheimer’s disease type 3 diabetes?

While not recognized as a medical diagnosis, some use the term to describe the strong—yet complicated—link between diabetes and the risk for Alzheimer’s disease (AD). Scientists aren’t entirely clear on how the two are connected, but certain factors may change the discussion around preventing and treating Alzheimer’s.

What is Type 3 Diabetes?

Experts say that the term “type 3 diabetes” is controversial and not commonly used among doctors and the medical community.

In recent years, however, emerging research has shown a link between Alzheimer’s disease, high blood sugar, inflammation, and insulin resistance. These last three conditions are also significant precursors to type 2 diabetes. The link is so strong that many call Alzheimer’s “diabetes of the brain” or “type 3 diabetes.”

While poorly-controlled blood sugar, insulin resistance, and inflammation may play a role in the risk for Alzheimer’s, the underlying mechanisms aren’t fully understood. And not all cases of Alzheimer’s disease are caused by these factors.

Diabetes and Alzheimer’s Disease

While a direct link between diabetes and Alzheimer’s Disease has yet to be proven, there has been a lot of research around this subject.

People who have type 2 diabetes have an increased risk of Alzheimer’s disease and the metabolic changes that occur in diabetes seem to accelerate the disease process.

• A 2024 meta-analysis in the journal Diabetology & Metabolic Syndrome showed a strong association between diabetes and an increased risk of dementia. The risk was higher when diabetes was present for less than 5 years and in those who had hypoglycemia.
  
• A 2024 study in PLOS One found that people who are diagnosed with type 2 diabetes at a younger age have a higher risk of developing dementia than those diagnosed later in life.
  
• A 2022 study in the International Journal of Molecular Sciences found people with type 2 diabetes may be between 45% and 90% more likely to develop Alzheimer’s disease.

Insulin Resistance and Alzheimer’s Disease

Many believe the link between Alzheimer’s and diabetes is due to insulin resistance.

The pancreas creates insulin, which then moves sugar from your blood into your cells, where it is used for energy. With insulin resistance, sugar is no longer moves into cells and begins building up in the body, causing high blood sugar and inflammation. This could lead to further issues such as high blood pressure, high cholesterol, heart disease, fatty liver disease, and—eventually—type 2 diabetes.

What does this have to do with Alzheimer’s? Type 3 diabetes manifests as insulin resistance within the brain and has the potential to impact cognition and may contribute to the onset and worsening of AD.

When someone has insulin resistance, the pancreas continues to try to regulate blood sugar, producing more insulin. These higher levels of insulin in the bloodstream can ultimately reach the brain.

The enzyme that breaks down insulin in the brain also breaks down the amyloid proteins in the brain. These proteins can develop into the plaques involved in Alzheimer’s disease. When insulin levels are high, less of the amyloid proteins are broken down, which leads to more plaque buildup. In many instances, this buildup begins two decades before changes in memory and thinking.

Experts say, however, these factors alone aren’t enough to explain the development of Alzheimer’s disease. For example, those with diabetes may also have comorbid conditions such as metabolic syndrome, a combination of high blood pressure, high blood sugar, high cholesterol and triglycerides, and obesity. Metabolic syndrome increases inflammation and the risk of diabetes, which can both contribute to the Alzheimer’s disease process.

How to Reduce Your Risk

With some simple diet and lifestyle interventions, you can reduce your risk of type 2 diabetes, metabolic syndrome, and Alzheimer’s disease.

• A healthy diet that consists of whole foods, fiber-rich fruits and vegetables, lean protein, and healthy fats like those found in nuts and seeds. Consume complex carbohydrates like starchy vegetables and whole grains in moderation and limit refined grains, added sugars, and processed foods. The American Diabetes Association recommends Mediterranean, vegetarian or vegan, and DASH diets, among others.  
  
• Regular exercise on all or most days of the week can improve insulin sensitivity and control blood glucose levels, reduce blood pressure, support a healthy weight, and lower cholesterol—all risk factors for type 2 diabetes. Strength training, in particular, is even better than aerobic exercise for managing blood sugar.
  
• Getting an adequate amount of quality sleep has been shown to reduce the risk of type 2 diabetes. Practice healthy sleeping habits, such as making your bedroom cool & dark, turning off devices 2 hours before bedtime, and having a relaxing nighttime routine.
  
• Stress management is also important since research shows chronic stress amplifies inflammation, which leads to changes in the nerve cells in the brain and cognitive decline.

Clinical trials can possibly help identify new treatments for Alzheimer’s disease, as well as the causes to perhaps prevent it.

To learn about current clinical trials at Charter Research, call us at 407-337-3000 (Orlando) or 352-441-2000 (The Villages). You can also fill out the form on this page, and one of our representatives will call you within 24 hours (excluding weekends).