New research suggests the cold weather could kickstart fat burning activity in the body.
Researchers found exposure to cold temperatures increases levels of a newly discovered protein that helps form (good) brown fat, which generates heat, UC Berkeley reported.
The protein, dubbed Zfp516, also helps white fat store excess energy and become more similar to brown fat. The researcher found mice with higher levels of Zfp516 gained 30 percent less weight when on a high fat than those with lower levels.
"Knowing which proteins regulate brown fat is significant because brown fat is not only important for thermogenesis, but there is evidence that brown fat may also affect metabolism and insulin resistance," said principal investigator Hei Sook Sul, UC Berkeley professor of nutritional science and toxicology. "If you can somehow increase levels of this protein through drugs, you could have more brown fat, and could possibly lose more weight even if eating the same amount of food."
The Zfp516 protein was found to activate the uncoupling protein 1 (UCP1), which is found only in the mitochondria of brown fat involved in the generation of heat.
"The amount of UCP1 produced by brown-like fat cells will be lower than that of classical brown fat, but since 90 percent of the fat in our bodies consists of white fat, finding a way to make that tissue more brown-like could have a significant impact," Sul said.
When Zfp516 was disabled in mouse embryos, the embryos did not develop brown fat. In a second experiment, mice with higher levels of Zfp516 were able to convert more white fat tissue into brown-like fat when exposed to colder temperatures
"The brown-like fat, the kind converted from white fat tissue, is inducible by cold. Classical brown fat, the kind in babies and prevalent in rodents, always has a ton of UCP1 and mitochondria in order to perform thermogenesis," said co-lead author Jon Dempersmier, a Ph.D. student in nutritional science and toxicology.
The mice with overexpressed Zfp516 were also found to gain less weight than their littermates with unaltered proteins when both groups were fed a high-fat diet for several weeks.
"This suggests that the transgenic mice were protected from diet-induced obesity," Sul said. "This protein could become an important target for research into the treatment and prevention of obesity and obesity-related diseases."
The findings were published Jan. 8 in the journal Molecular Cell.
