A common type 2 diabetes drug called metformin may have an unexpected, but positive, side effect: New research suggests that people taking the drug appear to have significantly slower declines in thinking and memory as they age.
“Our six-year study of older Australians with type 2 diabetes has uncovered a link between metformin use and slower cognitive [mental] decline and lower dementia rates,” said study author Dr. Katherine Samaras. She’s the leader of the healthy aging research theme at the Garvan Institute of Medical Research in New South Wales, Australia.
“The findings provide new hope for a means of reducing the risk of dementia in individuals with type 2 diabetes, and potentially those without diabetes,” Samaras said.
Metformin helps the body use the hormone insulin more effectively. It’s known as an insulin sensitizer. Insulin helps usher sugar into the body’s cells to be used as fuel. People with type 2 diabetes don’t use insulin effectively. This is called insulin resistance.
“Metformin is an insulin-sensitizing medication. However, it has a number of other effects in cells which allow them to remain metabolically healthy,” Samaras explained.
Samaras noted that experts think that type 2 diabetes or insulin resistance may play a role in the degeneration of brain and nerve tissues, as well as lead to harmful changes in blood vessels. By boosting how well insulin works in the body, metformin may help hold off some of this damage.
The study followed more than 1,000 people, aged 70 to 90, for six years. At the start of the study, all of the volunteers were living at home and had no signs of dementia. They underwent a series of neuropsychological tests every two years.
Among the participants, 123 had diabetes and 67 were taking metformin.
People with diabetes who didn’t take metformin had a five times higher risk of developing dementia during the study, the investigators found.
The researchers noted that this isn’t the first study to show that metformin might be linked to lower dementia risk. Other studies have found a similar association. The authors aimed to see if the drug made a difference in declines in memory and thinking in an older group of people.
Samaras and her colleagues are now planning a three-year, randomized controlled clinical trial of metformin in people who don’t have diabetes but who do have a high risk of developing dementia.
