Food for Thought

What’s irisin? Glenn Cardwell brings us up to speed on this interesting hormone.  

Glenn Cardwell

‘Don’t you like to be the first person in your group to use a new word? Sitting at the dining table commenting: “Excuse me, you have a little bit of food on your philtrum”. Well now, rather than saying something dull like you have been out for a walk or a game of squash you can say that you have been increasing your irisin output. About a year ago, clever folk at Harvard University had a study published in the journal Nature. OK, it was a study done in mice, but it has really excited the research community and now we are seeing studies in humans too. In essence, it seems that when we exercise not only do we burn fat and sugar (glucose) we also produce a very interesting hormone called irisin.

Brown vs white fat cells Irisin then travels around the body and modifies fat cells by increasing the number of brown fat cells and reducing the number of white fat cells. This is good because brown fat cells burn fat while white fat cells store fat. And the brown fat cells keep burning fat after you have finished exercise. Simply put, exercise burns fat and helps create fat burning brown fat cells, courtesy of irisin. Wait, there’s more. Irisin also helps to fight insulin resistance, one key factor behind high blood glucose levels and type 2 diabetes.

More research coming There will now be a flux of research on irisin. A paper published in December 2012 showed that obese people had high levels of irisin, suggesting that more is being produced to help combat high blood glucose levels common in obesity. Irisin is not the only protein being secreted by the muscles. Active muscles produce hundreds of proteins, some doubtless acting as hormones, so irisin may be only one of a family of secretory peptides that act to keep us lean and healthy. They are part of the explanation why fit people live longer than those who watch endless hours of mind-altering, light-emitting technology.

What does it all mean? Be active. Be fit. Don’t wait for irisin tablets or injections. We have been disappointed in the past with weight loss breakthroughs. Early research like this just helps us to marvel and understand the human body. Once a few more studies are done then expect, about March 2014 I’d say, the charlatans to spruik potions that ‘boost your irisin’. Just roll your eyes and go for a walk and boost your own for free, while getting some vitamin D and a mental refresher at the same time.’

 Glenn Cardwell is an Accredited Practising Dietitian. Make sure you check out Glenn’s website.