Type 3 diabetes is a term used when Alzheimer’s disease is triggered by insulin resistance in the brain. This condition is most often used to describe people who have type 2 diabetes and are also diagnosed with Alzheimer’s or dementia.

Diabetes refers to a health condition where your body has difficulty converting sugar to energy. Typically, we think of two kinds of diabetes:

  • Type 1 diabetes is a chronic health condition in which your body doesn’t produce enough of the hormone insulin.
  • Type 2 diabetes is a chronic condition in which your body develops resistance to insulin, and your blood sugar level becomes very high as a result.

New research is proposing that Alzheimer’s disease should also be classified as a type of diabetes, called type 3 diabetes. But this classification is controversial, and most doctors aren’t ready to use it until more research is done.

Keep reading to find out what we know, and what we don’t, about type 3 diabetes.

There is already an established link between Alzheimer’s and type 2 diabetes. Since Alzheimer’s may be triggered by insulin resistance in your brain, some people say that Alzheimer’s is simply “diabetes in your brain.”

This claim has some science behind it, but it’s a bit of an oversimplification.

Over time, untreated diabetes can cause damage to your blood vessels, including the vessels in your brain. Since many people who have type 2 diabetes don’t know that they have the condition, those with type 2 diabetes have a higher risk of this kind of damage.

Diabetes also throws off the balance of chemicals in your brain, which may trigger Alzheimer’s. And high blood sugar causes inflammation, which may damage brain cells.

For these reasons, diabetes is considered a risk factor for a condition called vascular dementia. Vascular dementia can be a standalone diagnosis with symptoms of its own, or it can be a warning sign of what will develop further into Alzheimer’s disease.

The science of this is still shaky. For now, what’s been established is that there are cases of Alzheimer’s and dementia that do not have any demonstrated link to insulin resistance.

People who have type 2 diabetes may be up to 60 percent more likely to develop Alzheimer’s or dementia. One study of over 100,000 subjects with dementia pointed out that women with type 2 diabetes had a higher probability of developing vascular dementia than men.

Risk factors for type 2 diabetes include:

The symptoms of type 3 diabetes are the same as symptoms of dementia or early Alzheimer’s. These symptoms include:

  • memory loss that affects daily living and social interactions
  • difficulty completing familiar tasks
  • misplacing things often
  • decreased ability to make judgements based on information
  • sudden changes in personality or demeanor

There’s no specific test for Alzheimer’s or type 3 diabetes. Your doctor will ask several questions about your family history and your symptoms. Brain imaging, like MRIs and CT scans, can give your doctor a picture of how your brain is working. Cerebrospinal fluid tests can also look for indicators of Alzheimer’s.

If you have the symptoms of type 2 diabetes and Alzheimer’s and haven’t been diagnosed with either one, you may be sent for a fasting blood sugar test and a glycated hemoglobin test.

If you do have type 2 diabetes, it’s essential that you begin treatment for it. Treating type 2 diabetes could minimize damage to your brain and slow the progression of Alzheimer’s or dementia.

There are specific treatment options for people who have type 2 diabetes as well as Alzheimer’s. Lifestyle changes, such as diet and exercise, may be a big part of your treatment.

Losing 5–7 percent of your body mass can help stop organ damage caused by high blood sugar. A diet low in fat and rich in fruits and vegetables can also improve symptoms. If you smoke, you’ll be advised to quit smoking.

If you have both type 2 diabetes and Alzheimer’s, treatment for your type 2 diabetes is important to stop the progression of Alzheimer’s. Metformin is an anti-diabetes drug that may also help treat symptoms of dementia.

Prescription medications are available to treat cognitive symptoms of Alzheimer’s and dementia. Cholinesterase inhibitors like donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon) can be prescribed to improve the way that your body’s cells communicate with one another. Memantine (Namenda) may slow the progression of Alzheimer’s disease.

Other symptoms of Alzheimer’s and dementia, like mood swings and depression, may be treated with psychotropic drugs. Antidepressants and anti-anxiety medications are part of treatment in some cases.

Type 3 diabetes is a way of describing Alzheimer’s that’s caused by insulin resistance. So your outlook will vary according to several factors, including your diabetes treatment.

If you can treat your diabetes with diet, exercise, and medication, you may be able to slow the progression of Alzheimer’s or dementia.

Your outlook will also vary according to how soon your symptoms were discovered, and what your doctor thinks about your specific case. The sooner treatment begins, the better your outlook will be.

The average life expectancy for a person with Alzheimer’s is 8 to 10 years from the time that they’re diagnosed. But some people with Alzheimer’s can live as many as 20 years post-diagnosis.

If you already have type 2 diabetes, there are ways that you can lower your risk for developing type 3. Here are some of the proven methods for controlling type 2 diabetes and minimizing organ damage:

  • Exercise four times per week for 30 minutes per day.
  • Eat healthy foods rich in protein and high in fiber.
  • Carefully monitor your blood sugar according to your health team’s recommendations.
  • Take any prescribed medications on schedule and with regularity.
  • Monitor your cholesterol levels.
  • Maintain a healthy weight.