Fueling the Brain: The Impact of Glucose on Neurodegeneration

Nearly 40 million adults in the United States are estimated to be living with diabetes, a disease in which insulin, a hormone that helps regulate blood sugar levels, is either not produced or used properly, leading to abnormally high levels of blood glucose. Research has supported a strong association between Alzheimer’s disease and insulin resistance. Preventive neurologist and IND team member, Dr. Kellyann Niotis, discusses why chronically elevated blood sugar levels can negatively impact your brain health and risk of neurodegenerative disease.

Glucose metabolism in neurological function and dysfunction

Because the brain doesn’t have much room to store fuel, it relies on nourishment through it’s preferred food source - glucose. Dr. Niotis explains, “we have lots of insulin receptors in our brain that help our brain metabolize and take up glucose for very important cognitive processes.” High glucose levels in the blood stream impacts the glucose that is being delivered to the brain. Similar to what is observed peripherally, hyperglycemia or high blood sugar, can lead to insulin dysfunction in the brain, preventing effective utilization of glucose for energy.

Dr. Niotis states that, “high levels of blood glucose are directly neurotoxic. It can cause neuropathy or injury to our peripheral nerves. And in the same way, it can cause injury to the brain cells - neurons and astrocytes.” Brain imaging studies have shown us that the brain starts to utilize glucose in different ways, depending on its neurodegenerative disease state.

Dr. Niotis shares that in “Alzheimer’s disease, for example, we really see changes in the way glucose is metabolized in a part of the brain called the temporal lobe, as well as the parietal lobe. Whereas in Lewy body dementia, we really see changes to the way glucose is metabolized in the parietal lobe and the occipital lobe.”

The temporal lobe of the brain is involved in learning, memory, and language comprehension. The parietal lobe of the brain is involved in processing various forms of sensory information and spatial orientation, and the occipital lobe is largely involved in the processing and interpretation of visual stimuli.

Dr. Niotis explains that with neurodegenerative diseases, “we see a change in the way the brain starts regulating insulin signaling and up-taking glucose, and that causes eventual death of the brain cells in those particular regions.”

The importance of diet and exercise in maintaining metabolic and brain health

Thankfully, there are two straight forward ways in which we can reduce high blood sugar levels - diet and exercise. Dr. Niotis emphasizes the importance of strength training to build muscle mass, “because the more muscle mass you have, the better time your body is going to have at disposing high insulin or high glucose. Your muscles love to take up glucose.”

In addition to exercise, Dr. Niotis encourages a healthy diet free from highly processed foods or foods with high glycemic indexes, like refined carbohydrates, pastas, rice, or any sort of added sugar. While honing in on your diet and exercise routine can certainly help you to slim down and tone up, these changes go much further than physical appearance alone.

Dr. Niotis explains, “it’s not the aesthetic fat or the fat that lives subcutaneously, the fat that we all care about in the way that we look. It’s really [visceral] fat that's surrounding our organs, that is really metabolically unhealthy and secretes a lot of inflammatory chemicals, that can impact the brain and can cause brain atrophy and can impact your cognition.”

To learn more about how glucose metabolism impacts neurodegenerative disease, and the importance of diet and exercise, watch our conversation with Dr. Kellyann Niotis in the video above.

By Alicia J. Barber, PhD