Irisin - Fat Transforming Hormone

Irisin - Fat Transforming Hormone

January 22, 2012 0 Comments

You have probably heard me say this on more than one occasion, “fat loss is a hormonally-driven event.”

If you want to be leaner and healthier, your efforts must appeal to your underlying hormonal environment.

While delving into the topic, I came across some exciting new research that I thought I would share.

After all, it’s not everyday that researchers discover a NEW hormone!

The NEW hormone is called IRISIN.

It promotes insulin sensitivity and improves glucose tolerance, even when on a high fat diet.  It is released in response to muscular contraction making Strength Training essential for speeding up your metabolism and keeping you energized.

But here is the amazing part: it actually has the ability to turn White Fat cells into Brown Fat cells!

If you are wondering why this is so important, allow me to explain.

The body creates a few different forms of fat cells: White Fat cells (subcutaneous and visceral), and Brown Fat cells.

1) Subcutaneous White Fat cells lie between your skin and the underlying muscle tissue.  An essentially inert, stored deposit of energy (sometimes containing toxins).  Relatively harmless and even useful at times as long as the total amount is kept in check and the diet and environment you keep is fairly free of toxic load.

2) Visceral White Fat cells are very different.  Hidden deep beneath the surface of the outer-most muscle layer, these cells lie in and around the internal organs, and even within bone and muscle tissue - as a type of “marbling.”  It is particularly troubling because of its proximity to the main components of the circulatory system as well as the fact it is metabolically active.

How is visceral fat metabolically active you ask?

Well, visceral white fat cells actually have the ability to “talk” to each other and orchestrate complex sets of hormonal interactions, including the production of substances called adipokines that increase blood pressure, manipulate hunger and satiety states, create even MORE visceral fat, and decrease insulin sensitivity.  In short, they work to erode our health.

3) Brown Fat cells are also metabolically active and reside in and around the organs, however, for very different reasons.  Brown Fat cells are mitochondria-rich - possessed of their own little furnaces - allowing them to self-incinerate for the production of heat.  Which in turn keeps our organs warm while raising core temperature.  The result is an INCREASE in metabolic rate.  Newborn babies and infants have a higher proportion of Brown Fat cells for this very reason, to help keep themselves warm.

Now, in Strength Training, a substance called PGC1 is released, which in turn produces a protein called FNDC that splits into pieces.  One of these pieces is the new hormone IRISIN.

And it appears that IRISIN actually transforms White Fat cells into the heat-producing Brown Fat cells.  A very compelling reason to get involved in proper strength training.

Again, “fat loss is a hormonally-driven event.”  Remember that.

Till next time…

Coach C


Bostrom, P., Wu, J., et al. A PGC1-Dependent Myokine that Drives Brown-Fat-Like Development of White Fat and Thermogenesis. Nature. January 2012. Published Ahead of Print.

Reynolds, Gretchen. Exercise Hormone May Fight Obesity and Diabetes. The New York Times. 11 January 2012.

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