Scientists from the Fred Hutch Cancer Center have made progress in understanding the link between obesity and neurodegenerative diseases. Using a fruit fly model, they discovered that a high-sugar diet can lead to insulin resistance in the brain, impairing its ability to remove neuronal debris and increasing the risk of neurodegeneration. The study, published in PLOS Biology, sheds light on the impact of diet-induced obesity on brain function.
Dr. Akhila Rajan, the senior author of the study, explained that previous research has shown obesity to be an independent risk factor for neurodegenerative disorders, but the specific mechanisms connecting obesity to impaired brain function have remained unknown. In their study, the researchers found that prolonged exposure to high sugar levels can lead to insulin resistance in peripheral tissues. Building on this knowledge, they sought to investigate how an obesogenic diet affects brain function.
The researchers used fruit flies as their model and studied the effects of a high-sugar diet on glial cells, which support and protect neurons. They found that a high-sugar diet reduced the levels of a protein called PI3k, indicating insulin responsiveness in cells. The glial cells also had lower levels of another protein called Draper, which aids in the removal of neuronal debris. As a result, the glial cells were unable to clear neuronal waste from the brain.
While the study was conducted using fruit flies, Dr. Rajan emphasized the need for further research to determine if similar processes occur in humans. However, she suggested that maintaining insulin sensitivity in individuals prone to dementia, even if they are not diabetic, could potentially promote nervous system function. The findings provide additional motivation for doctors and patients to focus on a healthy diet and exercise, according to Dr. Raphael Wald, a neuropsychologist.
Dr. Manisha Parulekar, director of the Division of Geriatrics at HackensackUMC, agreed with the study’s findings and stressed the importance of early interventions and lifestyle changes to reduce the risk of neurodegenerative diseases. She also highlighted the need for equal access to these interventions from a population health perspective.
In future research, Dr. Rajan and her team plan to investigate the behavioral outcomes of diet-induced insulin resistance and further explore the relationship between diet and the brain. Dr. Wald expressed the need for similar studies in humans to confirm the suspected mechanisms, which could lead to new therapies for obesity and neurodegenerative diseases. Dr. Parulekar suggested exploring the benefits of starting lifestyle interventions at an earlier age and investigating the potential efficacy of newer diabetic medications.