For the study, Bendlin’s team gave memory tests to 150 adults with no mental impairments, at average age of 61. The researchers also measured insulin resistance and had the participants undergo a PET brain scan.
More than two-thirds of the participants had a parent who suffered from Alzheimer’s, about 40 percent had a gene mutation associated with increased Alzheimer’s risk and roughly 5 percent had type 2 diabetes, according to the study.
The researchers found insulin resistance was associated with poorer processing of sugar throughout the brain. Worse performance in immediate memory was linked to lower sugar metabolism in the left medial temporal lobe, the authors said.
The report was published July 27 online in JAMA Neurology.
Dr. Sam Gandy, director of the Center for Cognitive Health at Mount Sinai Hospital in New York City, said it appears there may be a difference “between the dementia related to full-blown diabetes, which seems to be primarily dementia caused by hardening of the arteries in the brain, and the mental impact of insulin resistance, which some investigators believe is associated with Alzheimer’s.”
In the brain, insulin helps transmit messages between cells, he noted.
“We have long thought of Alzheimer’s as a disease of defective brain signaling,” said Gandy, who had no role in the study. “Conceivably, there is also a disease of defective insulin signaling, which this paper would support.”
If that’s true, Gandy added, “then efforts at sensitizing the brain to insulin, using drugs such as pioglitazone [Actos, a diabetes drug], would make sense and might well lead to slowing of degeneration.”
Giliberto recommended healthy living as the best way to keep blood sugar under control and perhaps protect mental health.
“Increasing our health by reducing fats, reducing sugar, improving insulin resistance may reduce the risk of other factors, such as diabetes, on the susceptibility to Alzheimer’s disease and mental decline,” Giliberto said.
Copyright HealthDay News. All rights reserved.