A study conducted by the Harvard medical School and published in the journal Nature describes the discovery of a new “messenger” hormone the researchers called “irisin” (after the messenger goddess Iris in Greek mythology). Irisin may be an answer to how muscle cells chemically “talk” to other cells, particularly fat cells, and irisin’s messages seem to protect against diabetes and obesity.
Irisin forms in a complex series of reactions from a substance called PGC1-alpha, produced by muscles during exercise, and apparently leaves the muscle cells and delivers an important message to fat—“brown yourself.”
Brown fat, you see, is “good fat”, metabolically active, calorie burning. White fat, on the other hand, is just storage, and tends to collect around internal organs…visceral fat. And, visceral fat clearly increases our risk for unhealthy conditions including Type 2 diabetes.
The fact that irisin seems to stimulate white fat into “browning” itself is extremely significant, and helps explain how exercise benefits health in so many ways. Researchers hope to move some of the experiments performed on mice in this series to humans. One question is whether irisin administered as a drug provide the benefits of exercise to people unable to actually exert themselves.