Even for people who don't have diabetes or high blood sugar, those with higher blood sugar levels are more likely to have memory problems, according to a new study published in the October 23, 2013, online issue of Neurology, the medical journal of the American Academy of Neurology.
The study involved 141 people with an average age of 63 who did not have diabetes or pre-diabetes, which is also called impaired glucose tolerance. 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 in the study.
The participants' memory skills were tested, along with their blood glucose, or sugar, levels. Participants also had brain scans to measure the size of the hippocampus area of the brain, which plays an important role in memory.
People with lower blood sugar levels were more likely to have better scores on the memory tests. On a test where participants needed to recall a list of 15 words 30 minutes after hearing them, recalling fewer words was associated with higher blood sugar levels. For example, an increase of about seven mmol/mol of a long-term marker of glucose control called HbA1c went along with recalling two fewer words. 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," said study author Agnes Flöel, MD, of Charité University Medicine in Berlin, Germany. "Strategies such as lowering calorie intake and increasing physical activity should be tested."