Brown fat, which differs from white fat, is a special type of fat that is considered healthy. This fat has a unique ability to burn calories.
However, the calory burn only happens when the brown fat is active, which is rare in adults.
Here’s the big question: How can brown fat be increased and activated? And can this activation lead to such significant calorie burning that it aids in weight loss?
A German-Danish research team has advanced its hunt for the solution. They discovered that brown fat has a unique internal mechanism that, soon after activation, turns off its activity, preventing it from functioning for a long time. The scientists have pinpointed the protein that causes this stop-process in more detail. The name of this protein is AC3-AT.
Hande Topel, a senior postdoc in Kornfeld’s research group at SDU, said, “Looking ahead, we think that finding ways to block AC3-AT could be a promising strategy for safely activating brown fat and tackling obesity and related health problems.”
The study team used advanced technologies that could detect unknown gene products and predict hitherto unknown proteins to detect AC3-AT. They also studied mice whose genomes had been artificially modified to reduce AC3-AT.
The mice that lacked AC3-AT were shielded from gaining weight. Their bodies were just more adept at burning calories, and activating their brown fat raised their metabolic rate.
Co-author of the study, Ronja Kardinal, a Ph.D. student under Professor Dagmar Wachten, adds:
“AC3-AT is found in mice and humans. It has direct therapeutic implications for humans.”
While brown fat is less common in older people, confident adults can still activate it. Exposure to cold, such as a winter bath, initiates this activation. The body has to take extra measures to stay warm in chilly environments, one of which is to burn brown fat for energy.
Along with AC3-AT, the team found other significant proteins or gene variations that react to cold, such as AC3-AT.
The researchers caution that it is too soon to say whether or not these can be used to activate brown fat in human treatments.
Journal Reference:
- Khani, S., Topel, H., Kardinal, R. et al. Cold-induced expression of a truncated adenylyl cyclase 3 acts as a rheostat to brown fat function. Nat Metab (2024). DOI: 10.1038/s42255-024-01033-8