In recent years, you may have heard of Alzheimer’s disease being referred to as Type 3 diabetes. So, is Alzheimer’s a form of diabetes, and what exactly does this mean? According to Daniel Murman, MD, Nebraska Medicine neurologist, the term is controversial and is not widely used among most medical professionals or major health organizations.

“The term Type 3 diabetes and its link to Alzheimer’s has gained more attention in the last few years because some studies have found a relationship between high blood sugar and insulin levels in the blood, insulin resistance in the body and in the brain and risk of Alzheimer’s disease,” says Dr. Murman. “However, it is not accurate to say that all cases of Alzheimer’s disease are caused by diabetic mechanisms, even though these mechanisms may play a role in some patients.”

Here's what we know. People with Type 2 diabetes have a higher risk of Alzheimer’s disease, and metabolic changes that occur in diabetes appear to accelerate the Alzheimer’s disease process, explains Dr. Murman. Type 2 diabetes is associated with insulin resistance, a condition in which your cells don’t respond well to insulin. Insulin is the hormone that regulates blood sugar levels and helps glucose enter our cells to provide them with energy. When your cells don’t respond well to insulin, the body makes more insulin to get the necessary glucose.

One link between diabetes and Alzheimer’s has to do with the development of insulin resistance, which can result in high levels of insulin in the bloodstream, which eventually reach the brain. An enzyme that breaks down insulin in the brain also breaks down amyloid proteins that can develop into plaques. With higher insulin levels, less of the amyloid gets broken down, leading to more plaque buildup, which is an important first step in the Alzheimer’s disease process.

Despite this relationship, most medical professionals believe the term Type 3 diabetes is too simplistic as there are a variety of health issues and inter-related medical conditions that often co-occur with diabetes, such as the metabolic syndrome, that can also play a role in Alzheimer’s disease, notes Dr. Murman. Metabolic syndrome includes abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides and low-serum high-density lipoproteins. The metabolic syndrome not only increases the risk of diabetes but also stroke, heart disease, and sleep apnea, and increases inflammation and oxidative stress (imbalance of free radicals and antioxidants in the body), which can all impact the Alzheimer’s disease process.

“Importantly, type 2 diabetes and the metabolic syndrome are preventable and/or treatable conditions in many patients with lifestyle modifications that secondarily would lower your risk of Alzheimer’s,” Dr. Murman says. 

You can help reduce your risk for Type 2 diabetes, metabolic syndrome and Alzheimer’s disease by:

• Maintaining a healthy weight.
• Eating a healthy diet.
• Exercising regularly.
• Reducing your intake of simple sugars.

While family history and aging are also risk factors for Alzheimer’s disease, Dr. Murman says lifestyle factors play an important role in increasing your risk.

“We encourage people in their middle ages and older to keep up with their annual physicals so their doctor can check for things like high blood sugar, increased lipid levels such as high cholesterol, and blood pressure levels,” Dr. Murman says. “Treating abnormalities in these areas and changing an unhealthy lifestyle early on is one of the best ways to prevent Alzheimer’s disease.”

Early stages of dementia can be diagnosed in your doctor’s office with cognitive testing and then confirmed with brain imaging, neuropsychological tests, and biomarker testing for some causes of dementia, such as Alzheimer’s disease. “It’s important to diagnose early cognitive impairment, as now we have drugs that can help slow the progression of Alzheimer’s disease by 30% or more in its early stages,” says Dr. Murman.

There is still a lot we don’t know about Alzheimer’s disease. Still, ongoing research is helping us understand the disease better and the mechanisms in the body that lead to its development. There are many ongoing clinical trials, which we hope will someday help us prevent Alzheimer’s.”