Type 2 diabetes is linked to a two-fold or higher increased risk of developing Alzheimer’s disease. Researchers presented findings at Neuroscience 2019, the annual meeting of the Society for Neuroscience in Chicago, that delved into the link between dementia and the metabolic system in the brain.
“Not much is known about the connection between dementia and the metabolic system that fuels the brain,” Dr. David Holtzman, professor at Washington University and scientific director of the Hope Center for Neurological Disorders, said in a news release. “Further research can help us understand how to manipulate these functions for treatment purposes, as well as better identify the underpinnings of the disease.”
Some 5.8 million people in the U.S. are living with Alzheimer’s disease, with that number projected to double in the coming decades, according to the Alzheimer’s Association. Diabetes, meanwhile, affects over 30 million Americans, with the majority of them having Type 2 diabetes, the Centers for Disease Control and Prevention (CDC) reports.
Researchers have known for some time that impaired metabolic functions, like hormonal disorders, high levels of calcium in the blood, hypothyroidism or nutritional disorders could result in brain dysfunction, according to the National Institutes of Health (NIH).
In a past interview with Being Patient, epidemiologist Rachel Whitmer at the Kaiser Permanente Northern California Division of Research noted that “for people with Type 2 diabetes, things that elevate your risk [of dementia] are core glycemic control—if you’ve had a very acute high blood sugar or low blood sugar episode that puts you at higher risk.”
“We know that depression is a large risk factor for dementia in people with Type 2 diabetes and we know that the more vascular complications you have also elevates your risk,” she added.
A variety of studies presented at the Neuroscience 2019 meeting added further evidence to this link, and may provide scientists with more information to develop new therapies.
Past studies have shown that the main feature of Alzheimer’s disease is beta-amyloid plaques, though inflammation has also been found to be a major culprit. Researchers also understand now that impaired glucose metabolism—or the body’s process of using blood sugar for energy—can also have an effect on a person’s risk for dementia.
In one study presented at the conference, researchers examined the metabolic connection between Type 2 diabetes and Alzheimer’s disease. They focused primarily on how certain lifestyle factors—like eating a Western diet high in fats and sugar—could impact a person’s risk.
They examined how a Western diet would affect the insulin pathway in mice that developed Alzheimer’s disease. They found that mice who were given this diet experienced impairment in brain insulin signaling, which resulted in poorer memory and learning.
The researchers noted that both Alzheimer’s disease and Type 2 diabetes are “reaching epidemic proportions.”
In another study presented at the meeting, researchers analyzed how beta-amyloid accumulation could have a negative impact on glucose in the brain.
In the study, researchers concentrated on how glucose wasn’t properly delivered to neurons in the brain in mice with Alzheimer’s, leaving extra glucose in the blood, similar to what occurs with diabetes. But boosting glucose delivery to the brain’s neurons showed some promise as a possible treatment for Alzheimer’s disease, even after beta-amyloid plaques appear.
The question of whether metabolic problems lead to Alzheimer’s, or Alzheimer’s triggers metabolic impairment, is still being investigated. And while some past research has explored how diabetes drugs could be beneficial for Alzheimer’s patients, there is still no cure for the disease.
For people who are concerned about their risk of developing dementia or Alzheimer’s, however, experts urge them to make lifestyle changes to protect brain health. Lowering your risk factors for cardiovascular issues, like improving diet, exercise and blood pressure, can all help prevent cognitive decline and dementia.