A recent study found that high blood sugar may negatively affect brain health even in individuals who do not have diabetes. Although the relationship between blood sugar levels and brain health is well established in those with diabetes, this study is the first to investigate this link in people without the condition.

“Our findings indicate that individuals who do not have a diabetes diagnosis may still have elevated blood sugar levels that could negatively affect their brain health,” said Dr Jean Chen, the senior author of the study and a Senior Scientist at the Rotman Research Institute. . “Blood sugar levels exist on a spectrum; they cannot simply be categorized as healthy or unhealthy.”

The study, “Associations Among Glycemic Control, Heart Rate Variability, and Autonomic Brain Function in Healthy Individuals: Age—and Sex-Related Differences,” was recently published in the journal Neurobiology of Aging. It examined 146 healthy adults aged 18 and older. Researchers analyzed each individual’s blood sugar levels, brain activity through magnetic resonance imaging (MRI) scans, and heart rate variability using electrocardiogram (ECG) readings.

“The findings emphasize the importance of managing blood sugar through a healthy diet and regular exercise, as this benefits not just your body but also your brain,” said Dr. Chen, who is Canada Research Chair in Neuroimaging of Aging and a Professor of Biomedical Physics at the University of Toronto. “Additionally, it’s crucial to have regular checkups and collaborate with a healthcare provider, especially if you have been diagnosed with pre-diabetes.”

Main study findings

• Higher blood sugar was associated with decreased connections in brain networks. These networks play a crucial role in all aspects of cognition, including memory, attention, and emotion regulation.
• The effect was more substantial in older adults, but it was present across all ages; older adults generally had higher blood sugar than younger adults.
• The effect was also stronger in women than in men.
• In addition, there was a link between higher blood sugar and lower heart rate variability – the beat-to-beat change in an individual’s heart rate. Previous research indicates that higher heart rate variability is associated with better brain health.

In future work, the researchers could investigate how to improve brain function by changing heart-rate variability. Heart rate variability is an easier target for intervention than blood sugar, especially in nondiabetic individuals.