|Brown adipose tissue|
Public domain photo by Lucasmcorso at Wikimedia Commons
When we are exposed to low temperatures for some time, brown fat cells appear amongst our white fat cells. The new cells are known as "brite" cells (brown in white). Their appearance appears to be an adaptation to the cold conditions. The more brown cells we have, the more heat we can produce - and the more fat we can break down. The same process happens in mice.
Until now it's been thought that brite cells develop from special precursor cells and that they have a different source from white fat cells. When we return to warmer temperatures, the theory says, the brite cells are removed. Now a team of researchers at ETH Zurich has found that when mice are exposed to cold conditions, some of their white fat cells turn into brite cells. Once the mice are returned to a warm environment their brite cells change back into white cells. Genetic studies have shown that there is actually an interconversion between the two types of fat cells rather than a formation and destruction of of cells.
The researchers believe that the fat cell interconversion process takes place in humans as well as in mice. They hope to find a way to trigger white fat to change into brown fat in obese people, perhaps with the aid of a medication or a nutrient. The brown fat could trigger weight loss.
The increasing incidence of obesity in several countries has been termed the "obesity epidemic". It's a very serious problem not only for individuals but also for public health budgets. Obesity increases the risk for several major diseases. The production of extra brown fat could be a wonderful aid to weight loss.