Brown Fat – Don’t Be Left Out In the Cold!
There’s yet another “weight loss breakthrough” making the rounds in scientific circles… and this time it’s none other than fat itself.
Seems ironic, maybe even contradictory, until you realize that the research and buzz is about a unique and rare type of adipose tissue – referred to as “brown fat” – that bears very little resemblance to the ugly body fat we tend to loathe.
Brown fat – typically stored in small amounts around the neck – is officially referred to as brown adipose tissue (BAT), and is one of two main types of fat found in humans.
The Buzz Over Brown Fat
So why all the recent attention over brown fat? One reason is that a study led by Andre Carpentier at the University Hospital of Sherbrooke (first reported in the Journal of Clinical Investigation1) found that brown fat activity was increased in response to colder temperatures.
More importantly, they found men burned more calories when brown fat was activated by cold exposure — about 250 calories in three hours.
The big promise, or so it seems, is that if scientists can find a way to increase brown fat stores – whether by lifestyle changes or [ahem] drugs – then it could be at least part of the answer to the multi-billion-dollar weight loss puzzle.
More Brown Fat Research
In a study published in the Journal Science, a group led by Stephan Herzig at the German Cancer Research Center found a way to manipulate white fat into acting more like calorie-burning brown fat2.
To do this, they stimulated an enzyme known as cyclooxygenase-2 (COX-2), which plays a role in a variety of physiologic functions, from regulating blood pressure to controlling inflammation and contracting muscles.
Finally, the discovery that a hormone called irisin can increase brown fat in mice has health bloggers going crazy3. The possibility that stimulating this hormone might lead to greater brown fat stores and weight loss is certainly enticing.
Is Brown Fat The Answer to All of Our Weight Loss Troubles?
With some of these initial developments, it would seem that brown fat might be the medical breakthrough we have all been looking for. Just increase brown fat, and burn more calories by doing next to nothing.
However, I’d exercise a bit of caution before believing the hype – for several reasons:
1) COX-2 stimulation could INCREASE inflammation.
Most drugs on the market work by inhibiting COX-2, and there is a reason for that. COX-2 is an enzyme directly involved in the symptoms of inflammation and pain. To attempt to do the opposite in the name of increasing brown fat activation could be short-sighted.4 (Future articles and content from me will address inflammation in far greater detail, since I believe it is THE most pressing health crisis facing us today.)
2) Irisin is a total unknown
It is simply too early to tell whether animal studies will translate to humans without unintended side effects. About 10 years ago everyone was excited about the hormone Leptin based on animal studies5. However, in humans, increasing leptin created no weight loss results. (This is because of leptin resistance resulting from inflammation by the way.)
3) Cold exposure simply is not pleasant
The most promising and (in my opinion) safest part of the brown fat phenomenon is the results attained through cold exposure.
Subjects in multiple studies were able to achieve greater brown fat activation by exposing themselves to temperatures in the 60 degree range (of course with no protective clothing) while dipping their feet in ice water periodically.
Personally, I simply do not see most people doing this on a regular basis! It is kind of like exercising regularly and eating right. We might know it works… but we just don’t want to do it. I would put cold exposure in this bucket.
Furthermore, the calories burned are not necessarily from the activation of brown fat. By simply lowering the temperature around you, you force your body to burn more calories just to keep you warm. This is why drinking ice water is a pretty effective calorie burner.
Finally, it is not clear whether the cold exposure is cumulative in terms of creating and activating brown fat. If the results were cumulative and long lasting, then I think the promise would be much higher. If not, I am afraid this simply will not be adopted by a majority of the population.
Conclusion – Don’t Be Left Out In The Cold
I’ll be the first to admit that the initial research on brown fat shows promise. But it’s nothing earth-shattering… not yet, at least. If you are a brave soul who is willing to shiver your way thin, please post below and we can do some kind of informal experiment.
Also, I’d love to hear any other thoughts or concerns you have in the comment section below.
And finally, whether it’s brown fat or anything else, let’s continue to stay skeptical of so-called “breakthroughs” until the evidence is conclusive and the benefits are undeniable.
Your body will thank you for it.
Until next time,
Dr. Steven Sisskind
1. Journal of Clinical Investigation; Volume 122, Issue 2 (February 1, 2012) J Clin Invest. 2012;122(2):545–552. doi:10.1172/JCI60433
2. SciBX 3(20); doi:10.1038/scibx.2010.605
Published online May 20 2010
3. Nature (2012) doi:10.1038/nature10777
Also referenced here: http://www.huffingtonpost.com/david-katz-md/brown-fat_b_1237541.html
4. Nature Chemical Biology 6, 401–402 (2010) doi:10.1038/nchembio.375
5. J Clin Invest. 2008;118(7):2380–2383. doi:10.1172/JCI36284.