Interleukin-6, a signalling molecule, plays a key role in losing fat after exercise, researchers have discovered, overturning the prevailing belief that it's all down to the fight-or-flight hormone, epinephrine.
Researchers from the University of Copenhagen noticed that obese people who were taking the rheumatoid arthritis drug tocilizumab weren't losing abdominal fat. The drug increases cholesterol levels—and also blocks interleukin-6 activity.
They tested the theory on a group of 53 obese participants who took part in a 12-week exercise programme, which included regular sessions on a static exercise bike. Half were given a saline placebo drip, and the rest were instead drip-fed the drug.
Those on the saline drip lost around 8 per cent of visceral fat—which accumulates around the heart and liver—but there was no fat loss among those given tocilizumab. They also had higher levels of cholesterol as a result of taking the drug.
People who are obese or suffer from type 2 diabetes or heart disease tend to either have low levels of interleukin-6, the researchers say, or whose interleukin isn't signalling healthily.