Obesity linked to significant risk of developing brain diseases

SEATTLE, Wash. — Obesity significantly increases the risk of developing neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease, a new study warns. Researchers from the Fred Hutchinson Cancer Research Center have discovered a link between excess weight and insulin resistance in the brain.

The team found that a high-sugar diet leads to insulin resistance in the brain, which then impairs the cleanup of neuronal waste. This increases the risk of neurodegeneration, which causes disease, by triggering inflammation, brain cell death, and poor nervous system recovery.

The study authors chose to look at high-sugar diets specifically, as overconsumption of sugar is the leading cause of obesity and other conditions such as Type 2 diabetes. To get the results, they studied the common fruit fly, which has lots of similarities to humans.

sugar fly
Sugar fly. Artistic rendering generated by DALL.E the prompt used is “The drawing of the fruit fly Drosophila in a dark background in the style of Seurat”. The researchers fed fruit flies high-sugar diets and examined the effect on brain function. CREDIT: Akhila Rajan created this image using DALL-E and owns it. They are making it available under CC-BY 4.0 (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)

Having previously shown that a high-sugar diet leads to insulin resistance in the peripheral organs of flies, the researchers turned to their brains.

“With increased life expectancy, age-related neurodegenerative disorders are expected to rise, placing a tremendous burden on the healthcare system,” researchers Mroj Alassaf and Akhila Rajan write in the journal PLoS Biology.

“Large-scale epidemiological studies have found that mid-life obesity is an independent risk factor for developing neurodegenerative disorders. Our study provides a strong mechanistic insight into how diet-induced obesity alters glial function, thereby increasing the risk of neurodegenerative disorders.”

Exactly how one leads to the other remains a mystery, but this study brings us a lot closer to understanding the correlation.

“Using fruit flies, the authors establish that high-sugar diets trigger insulin resistance in glia, disrupting their ability to clear neuronal debris. This study provides insight into how obesity-inducing diets potentially contribute to the increased risk of neurodegenerative disorders,” the study authors conclude in a media release.

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South West News Service writer Isobel Williams contributed to this report.

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