New research conducted at the UCLA School of Medicine has provided insight into the activation of brown fat, a specialized fat that generates heat and burns calories. Brown fat differs from white fat, which is typically associated with obesity, as it stores energy rather than burning it. The study, led by endocrinologist Preethi Srikanthan, involved dissecting the necks of eight human cadavers to trace the nerve pathways that connect brown fat to the brain. The researchers discovered that nerves from brown fat traveled to the third and fourth cranial nerves, which control blinking and eye movements. This finding suggests that altering the nerve supply to brown fat could potentially lead to new treatments for obesity and metabolic diseases like type 2 diabetes.
The study also highlighted the potential role of medications such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) in affecting brown fat activity. These medications belong to a class of drugs known as GLP-1 receptor agonists and have been shown to increase brown fat activity indirectly, through activation of specific regions in the brain. However, the scientific literature on this topic is divided, and further research is needed to fully understand the link between these medications and brown fat.
While the discovery of the precise nerve pathways connecting brown fat to the sympathetic nervous system opens the door to potential future obesity treatments, it is important to temper expectations. Brown fat depots are small and may have a limited overall contribution to whole-body energy balance in humans, according to Varman Samuel, an associate professor of medicine at the Yale School of Medicine. However, there is still much to learn about how different tissues communicate and how activating brown fat could potentially coordinate whole-body energy metabolism.
Overall, this research provides important insights into the potential therapeutic possibilities of activating brown fat for obesity treatment. Further studies are needed to explore the potential of stimulating these nerve pathways through medication, electrical stimulation, or heat therapy. While the contribution of brown fat to overall energy balance may be limited, there may be undiscovered mechanisms at play that could have a significant impact on metabolism and obesity treatment.