Dementia and Diabetes Link
New research shows a possible link between a common pre-diabetic condition and Alzheimer’s disease. Researchers believe that insulin resistance may interfere with the brain’s ability to process new information.
It is known that older people with diabetes are more likely to have dementia. A long term study published in the journal Neurology followed test subjects for 11 years and found that those who are 60 or older that have type 2 diabetes are almost twice as likely to develop dementia. What is not known is what causes this increase in risk.
Conditions which are linked to type 2 diabetes, such as high LDL cholesterol, high blood pressure and obesity, are also associated with dementia, so isolating a cause and effect relationship is a challenge. A common hypothesis was that high glucose levels somehow interfered with brain function, but recent findings may dispel this. In 2011 a study was published by The Lancet that found even tight control of blood glucose did not prevent dementia in study subjects.
Insulin May Be the Link
The direct cause of why the pancreas stops producing insulin is not fully known, but Northwestern University professor of neurology William Klein, PhD, has made a connection between a protein forming something called “oligomers” in the brain. Klein introduced the theory that oligomers are the true cause of Alzheimer’s and his research has shown the brains of study animals with diabetes contain many oligomer molecules.
Further study revealed a link between insulin in the brain and the formation of the molecule. According to his research lack of insulin in the brain seems to incite the formation of oligomers, and conversely, “Insulin itself makes the brain resistant to oligomers,” says Klein.
Several recent studies support this theory. In January 2012 a report in the Archives of Neurology revealed that after 4 months of nasal insulin injection, participant’s memories improved. In April 2012 the Journal of Clinical Investigation published an animal study which revealed improved cognitive function in mice and the diabetic medication “blocked the toxic effects” of the oligomer compounds.
While additional research needs to be conducted to confirm these findings, the promise of an Alzheimer’s treatment has the medical community excited. This research may also bring a better understanding of the mechanics behind diabetes, and therefore better treatment and prevention plans as well.