A hormone is released during exercise that not only helps the body to shed fat, but also prevents fat from forming, a new study has shown. The hormone, named irisin, was discovered by a team of researchers at Harvard Medical School in 2012.
The scientists found that as irisin levels rise during exercise, the hormone switches on genes that convert white fat into brown fat. This conversion is beneficial as brown fat burns off more excess calories than exercise alone.
The latest research was headed by Professor Li-Jun Yang, from the Department of Pathology, Immunology and Laboratory Medicine at the University of Florida’s College of Medicine. The aim of the study was to understand the role of irisin better and to increase the knowledge base of how the hormone helps convert calorie-storing white fat cells into energy-burning brown fat cells.
Irisin increases body's fat-burning capacity
Irisin works via a mechanism that boosts the activity of genes and a protein crucial to turning white fat cells into brown fat cells. The researchers also found irisin to have a role in burning fat by significantly increasing the amount of energy used by brown fat cells.
Professor Yang and team conducted the research by collecting fat cells donated by 28 participants who had undergone breast reduction surgery. Scientists exposed the fat samples to irisin, and as a result, saw an almost fivefold increase in cells that contain the UCP1 protein, a protein crucial to fat burning.
"We used human fat tissue cultures to prove that irisin has a positive effect by turning white fat into brown fat and that it increases the body's fat-burning ability," says Professor Yang.
Among the analysed fat tissue samples, the study found that irisin suppresses fat cell formation by reducing the number of mature fat cells by 20 to 60 percent, when compared with the control group.
While the beneficial effects of irisin could potentially be developed into therapies in the future, the viability of an irisin-based treatment is uncertain and would not happen imminently. Professor Yang comments: "Instead of waiting for a miracle drug, you can help yourself by changing your lifestyle. Exercise produces more irisin, which has many beneficial effects including fat reduction, stronger bones, and better cardiovascular health."
The researchers note that they believe the study to be the first of its kind to explore irisin's effects on human fat tissue and fat cells and confirms previous conclusions that irisin may be a promising target to support people with obesity and type 2 diabetes.
The findings of the study are published in the American Journal of Physiology - Endocrinology and Metabolism.
