People living with Type 2 diabetes are known to be at greater risk of developing Alzheimer’s disease, but the reasons behind this association were unclear.
New research from Wake Forest University School of Medicine in North Carolina reveals that increased sugar consumption and elevated blood glucose levels alone can trigger the growth of toxic proteins in the brain, a key indicator of the disease.
Sugar Helps Toxic Proteins Form in the BrainUsing mice, Wake Forest researchers found that consuming sugar water instead of regular drinking water led to the formation of more amyloid plaques in the brain.
To understand what drives this phenomenon, the researchers identified metabolic sensors called adenosine triphosphate (ATP)-sensitive potassium channels (KATP channels) that play a role in this process.
By removing these sensors from the brains of test mice, researchers discovered that the increase in blood sugar no longer raised amyloid protein levels or led to plaque formation.
They also examined the expression of these metabolic sensors in the brains of people with Alzheimer's disease and observed similar changes associated with the disease.
These findings suggest that these sensors may have a role in the progression of Alzheimer's and could potentially be targeted for future treatments.
This work is noteworthy because it identifies a potential drug target that links diabetes and Alzheimer’s disease, Percy Griffin, who has a doctorate in molecular cell biology and is the director of scientific engagement for the Alzheimer's Association, told The Epoch Times. The study also adds to people's understanding of exactly how known risk factors operate to raise or lower Alzheimer’s risk.
Earlier Onset Diabetes Increases Your Risk for Alzheimer'sIn a 2021 study of 10,095 people from 1985 to 2019, researchers documented 1,710 cases of diabetes and 639 cases of dementia. They observed that for every 1,000 participants examined every year who did not have diabetes by age 70, only about nine developed dementia.
However, for participants diagnosed with diabetes, the rates of dementia per 1,000 were 10 for people diagnosed up to five years earlier, 13 for six to 10 years earlier, and over 18 for a diabetes onset of over 10 years earlier. These findings suggest that an earlier diagnosis of diabetes is linked to an increased risk of significant cognitive decline. This association is likely attributed to prolonged exposure to elevated blood sugar levels, heightened damage to blood vessels resulting in reduced oxygen supply to the brain, and potential impact on brain cells due to insulin resistance.
The study authors emphasized that cardiovascular damage due to diabetes was unlikely to account for what they observed. They hypothesized that brain metabolic dysfunction is the primary driver of Alzheimer's disease, "highlighting the role of decreased transport of insulin through the blood-brain barrier, impairments in insulin signaling, and consequently decreased cerebral glucose utilization," the study authors wrote.
Dr. Jonathan J. Rasouli, director of complex and adult spinal deformity surgery at Northwell Staten Island University Hospital, emphasizes the importance of diet in preventing cognitive decline.
“Scientists have long suspected a link between sugar intake, insulin resistance, and eventual development of neurodegenerative disorders such as Alzheimer's disease,” he said.
In Type 2 diabetes, insulin resistance is the underlying issue with sugar metabolism. When patients become insulin resistant, their bodies no longer effectively absorb dietary sugar from the bloodstream into healthy tissues. “As a result, sugar molecules hang around in the blood and do not get broken down for energy,” Rasouli added. “These molecules can ultimately damage the body if they stay around for too long.”
Clinical Trial Investigates Insulin Nasal Spray to Improve CognitionThere is evidence the brain is affected by insulin, and the direct introduction of insulin to the brain has shown potential benefits for cognition. The strong connection between insulin resistance commonly seen in diabetes and cognitive health has led some scientists to refer to Alzheimer's as "type 3 diabetes."
During the trial, participants will be randomized into one of four daily treatment protocols for four weeks: intranasal insulin, an empagliflozin pill, both, or a placebo. The nasal spray is designed to deliver insulin directly to the brain without affecting glucose levels.