Melbourne scientists find key pathway to weight loss

Brigid O’Connell Health reporter

A key pathway to turn on the kilojoule-burning ability of our own body fat to help us lose weight has been uncovered by Melbourne researchers.

RESEARCHERS have uncovered a key pathway to turn on the kilojoule-burning ability of our own body fat to help us lose weight. 

Unlike white fat, which stores energy, brown fat and beige fat — an inducible form of brown-like fat — burn energy. It was thought that brown fat existed only in babies and small mammals, to help maintain their body temperature.

But since researchers discovered in 2009 that it also ­exists in smaller amounts in the shoulders and neck of adults, a global race has been on to “flick the switch” on these fat cells and their beige cousins to aid weight loss.

Professor Brian Oldfield, from the Department of Physiology at Monash University, said while many other groups had been looking at peripheral processes happening in the fat itself, his research team investigated how the central nervous system — the body’s complex processing centre led by the brain and spinal cord — interacted with fat.

They studied the central nervous system of rats, who had been kept at either 8C or 27C for a week, with the cold known to activate the process that turns white fat “brown-like”.

They found a “rewiring” of the pathways in the central nervous system when rats were exposed to cold and white fat cells were “beiged”.

They also found unique changes in chemical messages in the “last relay” of nerve cell connections that travel from the brain, down the spinal cord and from this last relay ­directly to the transformed beige fat cells.

The findings were presented at the Australasian Neuroscience Society’s Annual Scientific Meeting in Hobart yesterday.

“It refocuses the spotlight on the co-ordination of these events in the central nervous system bringing this to centre stage and de-emphasises the role played by peripheral processes happening in the fat,” Prof Oldfield said.

“We know that for such events to be properly orchestrated in a way that will help animals and humans react properly to changes in ­temperature and diet, there has to be co-ordination of that change in the central nervous system.”
 
He said finding this important pathway was a step closer to the holy grail of identifying the key process that could be changed, mimicked or blocked to turn “bad fat to good fat”.

“The issue is that there is a finite amount of bona fide brown fat in humans — only about 50-70g,” Prof Oldfield said. “The hope is that by inducing brown-like fat you can improve the capacity to burn energy.

“It’s a matter of trying to find the gateway to activating those pathways.”