Diabetes and Alzheimer’s disease are serious health challenges affecting increasing numbers of people in the United States and worldwide.
Although diabetes is an endocrine disorder and Alzheimer's is a neurodegenerative disease, these conditions have more in common than you may think. In fact, the relationships between the two are so pronounced that some researchers have called Alzheimer's “type 3 diabetes.”
Type 3 diabetes is not an official diagnosis or a widely accepted term; however, there is increasing recognition of the close connections between diabetes mellitus and Alzheimer's disease.
Why Alzheimer’s Is Referred to as “Type 3 Diabetes”
Of all the diabetes and Alzheimer's links, insulin resistance is the most obvious.
Insulin is required for the uptake of glucose, which is the fuel used by the mitochondria in your cells to generate energy. Insulin transports glucose into your cells by attaching to insulin receptors, unlocking the channels that let glucose in. When the cells don’t respond to these signals, glucose cannot enter, and blood sugar remains elevated. This is known as insulin resistance, and it is the crux of type 2 diabetes.
What does this have to do with Alzheimer’s disease? Insulin is also active in the brain, yet it has a different job there. Rather than moving glucose into the cells, insulin serves as a critical growth factor that promotes the development, maintenance, and survival of neurons, synapses (connections between neurons), and other brain cells such as glia and microglia.
Like cells elsewhere in the body, brain cells can become resistant to insulin, and failure to respond to insulin signaling impairs function. In fact, research has linked insulin resistance with neuronal dysfunction and death, brain shrinkage, and the formation of the beta-amyloid plaques and tau neurofibrillary tangles that are characteristic of Alzheimer's.
Other Connections Between Diabetes & Alzheimer’s
Oxidative stress and inflammation play central roles in the onset and progression of diabetes and its many complications, including damage to the arteries and blood vessels. Type 2 diabetes is also associated with obesity—approximately 85% of the diabetic population is overweight or obese.
All these factors contribute to Alzheimer's disease:
- Oxidative stress: Your brain, which makes up about 2% of your total weight, consumes 20–25% of all the glucose your body uses to produce energy. The brain’s high metabolic activity and oxygen requirements make it vulnerable to oxidative stress, which damages brain structures and increases inflammation in the brain. Diabetes makes things worse by compounding the brain’s oxidative burden.
- Neuroinflammation: Microglia, which function as immune cells in the central nervous system, help clear away cellular debris in the brain. However, they can also cause excessive inflammation, and microglia-related inflammation promotes the progression of Alzheimer’s disease.
- Vascular problems: Blood vessel damage, impaired blood flow, and other common cardiovascular complications of diabetes reduce the delivery of blood, oxygen, and nutrients to the brain. This is another reason why people with diabetes have a significantly greater risk of developing vascular dementia and Alzheimer's disease.
- Obesity: Obesity—especially in the abdominal area—increases insulin resistance, oxidative stress, and inflammation and is linked with faster cognitive decline, more significant brain atrophy, and increased risk of Alzheimer's disease.
A Risk Factor You Can Control
Let’s return to our original question: Does diabetes cause Alzheimer’s disease? Yes and no. Not everyone with diabetes develops Alzheimer's, nor do all people with Alzheimer's have diabetes.
Alzheimer's is a multifaceted disease with a number of underlying contributors, including age and genetic susceptibility. However, diabetes and its many metabolic abnormalities most certainly increase the risk of cognitive decline and dementia.
Since you can’t do anything about your age or your genes, it’s important to double down on the risk factors that you can control. There are many positive steps you can take to prevent Alzheimer's, and among the most important is getting a handle on diabetes.
Program for Reducing Risk
- Diet: A whole-foods, nutrient-rich, low-carbohydrate diet with a minimum of sugars and starches is not only helpful for controlling diabetes but also for enhancing brain health.
- Exercise: Physical activity most days of the week improves insulin sensitivity, cardiovascular health, and weight and delays or prevents cognitive decline.
- Weight loss: Losing as little as 10–15 pounds can improve blood sugar control and insulin sensitivity.
- Blood sugar-lowering supplements: Most of my patients with diabetes have had excellent results controlling their blood sugar with berberine, chromium, and other targeted supplements. Early research has also proposed berberine as a therapy for inhibiting or delaying the underlying pathologies related to Alzheimer's disease.
- Other protective supplements: Because oxidative stress and inflammation are common factors in the development and progression of diabetes, Alzheimer's, and most other chronic degenerative diseases, I recommend a comprehensive daily multivitamin with hearty doses of antioxidants plus supplemental fish oil.
Get Started Now!
Get started on this program today. Brain deterioration and cognitive decline associated with Alzheimer's disease begin years, and even decades before symptoms become obvious. Yet, it’s never too late to improve your health.
Even if you don’t have diabetes, consider adopting this program. In a study involving more than 5,000 English men and women, average age 65, who were followed for eight years, those with higher A1C levels had faster rates of cognitive decline, even if their blood sugar wasn’t high enough to be diagnosed as diabetes. One in three US adults (88 million) fall into this prediabetes category—and if you’re overweight, inactive, or have a poor diet, you’re likely one of them.
Sure, it takes work and focus to stick with such a program. Sitting on the couch and eating junk food is certainly easier and perhaps more enticing. But these simple lifestyle changes will increase your chances of a long, healthy, active—and memorable—life. And that’s a goal worth striving for.