Scientists in Switzerland are the first to show that the two different types of fat in mammals - brown and white fat - can be converted from one to the other, challenging current understanding of fat cell fate. So far this research has been done using mice, but in the future it might lead to potential anti-obesity treatments.
White fat is the blobby stuff under our skin and around our organs. These fat cells get filled up with fatty droplets in good times and emptied when we need extra energy. In contrast, brown fat is only found in certain places in the body - although there’s a relatively large amount in newborn babies - and burn fat and sugar to help maintain body temperature. Switching white cells into brown ones could be a handy way to lose weight by burning off extra calories, but until now this wasn’t thought to be possible.
Writing in the journal Nature Cell Biology, the scientists focused on so-called ‘brite’ fat cells, which are brown-type cells that form within white fat in response to cold temperatures. Using special cell-tracing techniques, they discovered that these cells are generated by white fat cells switching fate as it gets chilly, rather than being generated by specific brown fat precursor cells. And not only did white fat switch into brown when it gets cold, they can switch back when the temperature warms up.
The researchers are now trying to track down exactly how this works, so they can design drugs that might push fat cells from white to brown and help burn up more calories. Sadly, this isn’t going to help humans lose weight any time soon, but it’s an important step on the road to understanding how different types of fat are formed, and how they might be manipulated.