A new type of fat tissue has been discovered in the human and mouse body. Before you say “More fat?” you should know that this fat, called ‘Beige fat’ may have anti-obesity properties.
Fats are of Different Colours
Prior to the latest discovery, fats were known to be of two types. White fat cells are the ‘energy storers’ and brown fats are the ‘energy burners’. Brown fats produce high levels of a protein UTP1 which directs the respiration machine in the cell, the mitochondria, to work at higher levels. It thus burns up more energy. This fat has been known to prevent obesity and hypothermia in mice. White fat on the other hand produces low levels of the UTP1 protein and thus respires less, meaning that less of the fat gets burnt up. Brown fats are mainly present in human infants to protect them from the cold and in small mammals like rodents. Adults, unfortunately, have deposits of the energy-storing white fats.
Some ‘brown fat’ cells were previously seen within white fat tissue deposits in humans. However, these have now been found to belong to a new category of fats called ‘beige fats’. Like white fat cells, they show extremely low respiration in normal conditions but on exposure to cold or stimulation by a molecule called cAMP, they respire at rates comparable to brown fats. They can thus switch between energy storage and energy burning states unlike other fat cells. The presence of these cells may represent a conserved cellular mechanism for adaptive control of body temperature.
As with any new discovery, the existence of beige fats has thrown up new questions. We don’t know how much of it exists in our bodies yet. Is there any way we can specifically regulate the quantity of this fat for obesity treatments?