Blood sugar control is essential to the well-being of people with diabetes, which is linked to a number of complications, including memory loss. But one needn't have diabetes to feel the effects of out of whack blood sugar levels.
According to a new study, higher blood sugar levels may weaken the memory skills even of people who don't have diabetes.
Agnes Flöel, MD, of Charité University Medicine in Berlin, Germany, was this study's lead author.
Her team of researchers tested the memory skills and blood sugar (glucose) levels of 141 individuals who responded to advertisements for study participants. The average age of participants was 63. The group was almost equally divided between men and women.
None of the study participants had type 2 diabetes, a disease in which the body was a reduced ability to process insulin — a hormone that helps transport blood sugar (glucose) from the blood vessels into the tissues where it is used for energy.
Furthermore, none of the study participants had pre-diabetes, a condition in which a person is not diabetic, but has impaired glucose tolerance. Also excluded from the study were persons who were overweight, who drank more than three and a half servings of alcohol per day, which can cause blood sugars to spike, or who had difficulty remembering and thinking.
The researchers did brain scans to measure possible glucose-driven changes in the function and structure of study participants' hippocampus, a region of the brain that controls memory and learning ability.
The researchers found that people with the highest scores on tests of how well they could remember 15 words 30 minutes after hearing those words also were more likely to have lower blood sugar levels.
"These results suggest that even for people within the normal range of blood sugar, lowering their blood sugar levels could be a promising strategy for preventing memory problems and cognitive decline as they age," the study author said. "Strategies such as lowering calorie intake and increasing physical activity should be tested."
Being overweight and sedentary raises one's risk for developing diabetes.
According to the most recent available data, 8.3 percent of the US population (25.8 million people) were diagnosed with diabetes in 2011. Type 2 diabetes is the most common form. Other forms include type 1 diabetes, or juvenile diabetes, which strikes children, and gestational diabetes, which is triggered during some women's pregnancies.
This new study of blood sugars and memory was published online October 23 in Neurology.
The German Research Foundation, Else Kröner-Fresenius Foundation and German Ministry of Education and Research funded the study.
The authors reported no financial investments or other involvements that would have influenced study design, outcomes or analysis.