In a new study, experts from Harvard Medical School found there was a link between type 2 diabetes and memory loss.
They found that people with type 2 diabetes experienced more negative changes in their brain function over the space of two years than those who did not have diabetes.
The study involved 40 people with an average age of 66. Of those, 19 had type 2 diabetes and 21 did not have diabetes.
Participants with diabetes had been treated for the disease for an average of 13 years.
Each person's brain function was tested at the beginning of the study and again two years later, to assess how it altered over time.
Tests included cognition and memory tests, MRI scans of the brain to look at brain volume and blood flow, and blood tests to measure control of blood sugar and inflammation.
"Normal blood flow regulation allows the brain to redistribute blood to areas of the brain that have increased activity while performing certain tasks," study author Vera Novak said in a statement.
"People with type 2 diabetes have impaired blood flow regulation. Our results suggest that diabetes and high blood sugar impose a chronic negative effect on cognitive and decision-making skills."
After two years, people with Type 2 diabetes had significantly lower scores on several tests of memory and thinking skills.
People with lower ability to regulate blood flow at the beginning of the study also had greater declines in a measure of how well they could complete daily activities, such as bathing and cooking, when compared to other participants.
Commenting on the study, Dr Laura Phipps of Alzheimer’s Research UK said more research needed to be done around the links between type 2 diabetes and dementia.
"Though there is a well-established link between diabetes and an increased risk of dementia, this research did not look at that relationship directly but focused on memory decline in those without dementia," she said.
"This small study highlights a possible mechanism that could play a role in affecting memory and thinking skills in people with diabetes, but this association is complex and still not fully understood.
"We know that inflammation is being implicated in diseases like Alzheimer’s, and while it’s interesting to see it may also impact on the brain’s ability to divert blood flow, it’s hard to separate cause and effect in this kind of research. Studies involving more people, tested over longer periods of time, will be needed before a clearer picture can emerge."
She added that current evidence suggests eating a balanced diet, drinking in moderation, not smoking, keeping blood pressure and cholesterol in check, and staying mentally and physically active can all help to maintain a healthy brain as we get older.