People with diabetes may be at higher risk for neurodegenerative diseases like Alzheimer’s disease. But new research suggests that one drug commonly used to treat type 2 diabetes may also help reduce the risk of AD.
According to the Alzheimer’s Association, Alzheimer’s disease is the most common type of dementia, which is a condition that causes memory loss and other changes in intellectual ability. AD is a progressive condition that gets worse over time. There currently is no cure.
Diabetes is a condition that results when excess sugar accumulates in the blood. Cells in the body use sugar as a source of fuel. Insulin is a hormone that helps cells accept sugar from the blood.
When cells resist the work of insulin, excess sugar remains in the blood where it can damage systems throughout the body.
Type 2 diabetes develops when the pancreas is no longer able to produce enough insulin to supply the body’s needs.
According to an article in Scientific American, approximately 20 million people in the United States have type 2 diabetes. Of those, most of them use the drug metformin to help control their disease.
According to WebMD, metformin works by making muscle tissue more receptive to insulin. It also helps decrease the amount of glucose or sugar that is released by the liver in to the blood.
New research studies may have found a link between long-term metformin use and a reduced risk of dementia, including AD and Parkinson’s disease.
A study of 6,000 patients with diabetes showed that the longer a patient used metformin, the lower the risk of AD seemed to be. The Tulane University research showed that patients who used metformin for four or more years had only 25 percent of the risk of developing AD as patients who had not used the drug.
The study suggests that metformin may help protect the brain from effects of aging, including how the brain uses insulin as we age.
Neuroscientist Suzanne Craft told Scientific American that Alzheimer’s patients often show signs of decreased sensitivity to insulin in the brain, whether or not they have diabetes. Among other uses, insulin works in the brain to help keep neural pathways free from protein debris including tau tangles and amyloid plaques that are associated with AD.
Animal studies have shown that metformin may help correct issues with how the brain uses insulin in aging patients.
One study at Toronto’s Hospital for Sick Children showed a link between metformin and an increased number of neural stem cells that were available to develop into healthy neurons in the brains of non-diabetic mice.
Clinical trials on human patients show metformin may be useful in treating early AD.
A researcher from Massachusetts General Hospital observed that early AD patients who used metformin had small but significant improvements in mental function compared to patients receiving a placebo instead of the drug.
Further tests are needed to examine the value of metformin as an AD treatment.
Research is also underway concerning located biomarkers for AD that could provide an early warning for patients at high risk of AD.
This could one day allow high-risk patients to use metformin or other effective insulin sensitizers to prevent the start of AD, rather than waiting to treat it after symptoms begin to show up.
If you have questions about metformin or about your risk for Alzheimer’s disease, talk to your health care provider.
Reviewed November 30, 2016
by Michele Blacksberg RN
Edited by Jody Smith