What Your Brain Needs to Know About the Link Between Diabetes and Dementia

Diabetes affected 463 million people worldwide in 2019, according to the International Diabetes Federation. That number is expected to grow to 700 million by 2045. Diabetes is a major cause of blindness, kidney failure, heart attacks, stroke, and lower limb amputation and it may be partly behind the dementia epidemic. Diabetes can lead to brain damage, a decline in mental function, and accelerate or cause dementia. In honor of National Diabetes Awareness Month, let’s look at how diabetes can negatively impact brain function.

What Exactly Is Diabetes?

In order to understand how diabetes affects your brain, you need to understand how the different types of diabetes affect the body. Your body gets most of its energy by ingesting carbohydrates, which are broken down into sugars and utilized in different essential functions throughout your body. Insulin is a hormone that regulates the movement of sugar into your cells. When a person has diabetes, their body is unable to make or utilize insulin properly. This can result in high blood sugar levels that can cause severe damage to a person’s vision, heart, and nervous system over time.

Like the rest of your body, your brain depends on sugar to function. Pound for pound, your brain requires more energy than any other part of your body. Brain cells require two times the energy needed by other cells, which is about ten percent of your typical daily energy requirement. The brain’s primary fuel is blood sugar, called glucose. So, your brain needs sugar, but too much is damaging.

Type 1 and Type 2 Diabetes

Type 2 diabetes is a chronic condition that affects the way a body metabolizes sugar. In type 2 diabetes, your body either resists the effects of insulin or doesn’t produce enough insulin to maintain normal glucose levels. Type 2 diabetes used to be known as adult-onset diabetes because it most often develops in people over age 45. However, today more children are being diagnosed with the disorder, probably due to the rise in childhood obesity. There’s no medical cure for type 2 diabetes, but losing weight, eating healthy, and exercising can help manage the disease. If diet and exercise do not allow a person to regulate blood sugar, diabetes medications and insulin therapy are options.  According to the CDC, approximately 90-95 percent of diabetics are type 2.

Type 1 diabetes was once known as juvenile diabetes or insulin-dependent diabetes. It is a chronic condition where the pancreas produces too little or no insulin. Different factors, including genetics and some viruses, may contribute to type 1 diabetes. Although type 1 diabetes usually appears during childhood or adolescence, it can develop in adults. Despite extensive research, type 1 diabetes also has no cure. Treatment focuses on managing blood sugar levels with insulin, diet, and lifestyle to prevent complications.

Certain risk factors, including genetics, dietary habits, amount of exercise, and body weight, increase your chances of developing diabetes. Symptoms of diabetes are extreme thirst and hunger, frequent urination, blurry vision, slow-healing cuts and bruises, a sudden change in weight, or tingling, pain, or numbness in your hands and feet. Early detection is crucial for optimal diabetes management and can delay and even prevent some of the complications associated with the condition — including dementia. 

How Are Diabetes and Dementia Connected?

Studies show that type 2 diabetes has the strongest link to dementia. In fact, the link between Alzheimer’s disease and diabetes is so strong that some researchers believe that the disease may actually be the late stages of type 2 diabetes. Not all studies confirm the connection, but many suggest that people with diabetes, especially type 2, are at higher risk of developing Alzheimer’s or other dementias.

When poorly managed, diabetes can negatively affect the brain in multiple ways. It can cause damage to blood vessels and is a risk factor for vascular dementia. This type of dementia occurs because of reduced or blocked blood flow to the brain. Factors that increase your risk of heart disease and stroke, including diabetes, high blood pressure, high cholesterol, and smoking, also raise your vascular dementia risk.

Many people with diabetes have brain changes that are hallmarks of both Alzheimer’s disease and vascular dementia. Some researchers think that each condition fuels the damage caused by the other.

What the Research Says

A  study published in the journal Neurology found that people with type 2 diabetes were more likely to develop the brain “tangles” commonly seen in people with Alzheimer’s. They found that participants with type 2 diabetes were more likely to have brain tangles, even if they did not have dementia or memory loss.

Recent research published in The Journal of Alzheimer’s Disease found that high levels of insulin in the blood, known as hyperinsulinemia, due to early or undiagnosed diabetes, obesity, or prediabetes is also found in nearly half of all people with Alzheimer’s. If diabetes is not caught and treated early enough, hyperinsulinemia can develop and contribute to the development of Alzheimer’s. The condition of hyperinsulinemia occurs when the amount of insulin in the body is higher than normal and inhibits the pancreas’ ability to secrete the amount of insulin needed to maintain glucose levels. This can lead to dangerously low blood sugar. Your brain also produces insulin and hyperinsulinemia inhibits brain insulin. This can result in an impaired ability to clear amyloid plaques, increasing the risk of Alzheimer’s.

Similarly, people who already have dementia are more likely to have hypoglycemic episodes, periods of low blood sugar. Hypoglycemic episodes have been found to cause brain damage in the cerebral cortex and hippocampus. This increases a person’s chance of developing diabetes. Some medications can increase hypoglycemic episodes. This can be especially problematic for elderly dementia patients. If medications cause the same symptoms as diabetes, the condition can be overlooked. Also, a person with dementia may not be aware of symptoms. Therefore, a vicious cycle exists between dementia and diabetes that can be difficult to manage as they both affect one another.

What You Can Do to Prevent Diabetes and Dementia

While there are no guarantees, you can take steps to lower the chances of developing diabetes and dementia. Healthy lifestyle factors reducing the chance of type 2 diabetes include:

• Healthy diet
• Maintain a healthy weight
• Manage blood pressure
• Manage cholesterol
• Regular exercise
• Quit smoking

For people with type 1 diabetes, the chances of mental decline can be reduced by early diagnosis and proper management of glucose levels with insulin. Those with type 2 diabetes can decrease their chances of dementia by managing symptoms and adopting healthy lifestyle habits. To decrease your chances of developing dementia, you can adopt a brain-healthy lifestyle. Ideally, elderly diabetics would be monitored closely to catch changes early.

Although current research confirms a link between dementia and diabetes, there are still specific details to be discovered. The best way to prevent either condition from occurring or worsening is by adopting a healthy lifestyle. It’s important to know the causes and warning signs for both conditions.