High Blood Sugar: How Our Brain Reacts
With diabetes, we know controlling blood glucose is important for heart, nerve, eye, and kidney health, but we don’t often hear about high blood sugar’s effect on the brain.
Though diabetes has a subtle influence on the brain, its impact on our executive, memory, learning, and concentration processes is measurable. This makes sense according to Indiana University’s neuroscientist Dae-Jin Kim.
“Our brain consumes about 25 percent of the blood in our body,” said Kim. “So, the glucose in our blood should affect our brain the most.”
Brain Buzz and Hyperglycemia
A recent study done by Kim and some colleagues looked at the effect of diabetes on the communication between different areas of the brain, areas that need to be well integrated for optimal mental activity.
The scientists took MRI scans of 144 specialized brain regions in people with poorly controlled type 2 diabetes, and in non-diabetic participants, then analyzed the connections between the brain regions.
The analysis revealed that amidst the different brain areas, communication path lengths were longer in those with diabetes, and the white matter appeared structurally disrupted. “Chronic, uncontrolled hyperglycemia may induce tiny changes in the white matter tract, which may force changes in the brain network,” said study coauthor, Min-Seon Kim.
Though the researchers don’t know how, or whether this study applies to people with well controlled diabetes, their work may give some people added incentive to exercise regularly, and skip a few sugary snacks.
New Neurons and Hyperglycemia
Another interesting study used zebra fish - excellent life-forms for investigating human disease - to look at the effect of high blood sugar on neurogenesis, or the creation of new neurons.
Some zebra fish were given one exposure to elevated blood sugar, while others were given continuous exposure for two weeks:
- After 24 hours, all the fish demonstrated normal neurogenesis.
- After 14 days, the fish exposed to continuous elevated glucose showed an alarming decrease in neurogenesis—down 50 to 65 percent in some brain regions.
- After receiving a lab-inflicted brain injury, the fish that received short-term high glucose exposure generated new neurons in the damaged area, but the fish that experienced two-weeks of hyperglycemia did not generate new cells.
This zebra fish study happily suggests that occasional spikes in blood sugar do not inhibit the birth and growth of new neurons in the brain. However, it also warns that uncontrolled high blood sugar might limit the brain’s ability to restore aging or damaged neurons.
Together, these hyperglycemia-brain studies imply that daily efforts to regulate our blood sugar make a significant connective and generative difference to the neural networks and cells of the brain.