Study author Dr. Agnes Floel of Charite University Medicine in Berlin said people with lower blood sugar levels were more likely to have better scores on the memory tests.
The study involved 141 people with an average age of 63 who did not have diabetes or pre-diabetes. They were asked to recall a list of 15 words in 30 minutes.
People who were overweight, drank more than three-and-a-half servings of alcohol per day, and those who had memory and thinking impairment were not included. Participants also had brain scans to measure the size of the hippocampus area of the brain, which plays an important role in memory.
The study, published online in the journal Neurology, found those who recalled fewer words were associated with higher blood sugar levels. In addition, people with higher blood sugar levels also had smaller volumes in the hippocampus.
"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," Floel said in a statement.
"Strategies such as lowering calorie intake and increasing physical activity should be tested."