- Exposure to cold temperatures causes stem cells to form brown fat instead of white fat, according to a new study.
- Brown fat causes our bodies to burn extra calories to keep warm — so if we can produce brown instead of white fat, that could help us burn off excess body fat.
- This adds to the body of knowledge demonstrating that exposure to the cold might have real health benefits.
If you want to lose weight, you might consider getting comfortable with the cold.
A new study published in the Nature journal Scientific Reports has found evidence that exposure to cold temperatures could transform the type of fat we form in our bodies, and even potentially help us burn off excess body fat.
For the research, scientists differentiated stem cells (which can become other types of cells) to become fat cells at both normal body temperature and at a slightly cooler temperature. They found that at the lower temperatures, the cells formed a kind of fat known as brown fat, which causes bodies to burn more calories to keep warm and burn off excess body fat.
People always have some layer of fat in their bodies. Adults have mostly white fat, which serves as a sort of solid, inert way of storing energy. White fat is what makes up dangerous excess body fat. Brown fat, on the other hand, is used to rev up the metabolism to keep us warm — it’s how babies regulate their body temperature, since they don’t have the muscles to shiver themselves warm yet.
Researchers once thought we lost this type of fat as we left childhood, but they now know there’s at least a small amount left in adults. That realization gave scientists hope that they could figure out how to activate and even stimulate the growth of this brown fat in our bodies, which could help people burn off extra calories — including the white fat many of us have stored around our bellies.
This new study brings us a step closer to that.
Harnessing the power of brown fat
“It has been known for quite some time that exposure to lower temperatures can promote the formation of brown fat, but the mechanism of this has not yet been discovered,” study author Virginie Sottile, an associate professor at the University of Nottingham in the UK, said in a statement. “The trigger was believed to be the body’s nervous system and changes in the way we eat when we are cold. However, our study has shown that even by making fairly modest changes in temperature, we can activate our stem cells to form brown fat at a cellular level.”
That finding is promising for three reasons. First, it helps reveal more about the mechanism that causes brown fat to be produced in the cold. Second, it shows that those changes can happen with a difference of a few degrees: In the study, cells turned into brown fat instead of white at 89.6 degrees Fahrenheit (32 Celsius) instead of the normal human body temperature of 98.6 degrees (37 Celsius). Third, the research suggests that the production of brown fat can be triggered by environmental change and doesn’t rely on special cells that always produce brown fat.
“The good news from these results is that our cells are not pre-programmed to form bad fat and our stem cells can respond if we apply the right change in lifestyle,” Sottile said.
This study doesn’t tell us how much cold people need to expose themselves to in order to produce brown fat instead of white. But it’s another piece of data in support of the idea that exposing yourself to the cold — a practice that’s becoming more popular — has some real health implications.
Studies of this brown-fat-production mechanism may even eventually reveal a way to trigger brown fat production with a drug instead of cold exposure, which can be extremely uncomfortable.
The health benefits of the cold
Growing numbers of people are opting to take cold showers and ice baths due to beliefs that cold exposure can transform the body. Some extremists even go hiking or mountain climbing in cold weather without much protective clothing.
The idea behind this “environmental conditioning,” as Dutch fitness guru Wim Hof explains it, is that our bodies evolved to be challenged by factors like extreme cold and heat. In modern conditions that lack those stresses, our overall stress response may go haywire. That’s why Hof, also known as “Iceman,” advocates for a combination of environmental conditioning and controlled breath work; he says the practice can have a transformative effect on health.
While it may sound like a pseudoscience trend, there is some evidence that programs like Hof’s might have real effects. Some data indicates that Hof’s regimen has led to measurable benefits in certain individuals including better fat-burning capabilities, weight loss, an improved immune system, and the ability to counteract some effects of Type 2 diabetes.
Scientists still have a long way to go to fully understand how the cold impacts us, but this new study lends support to the idea that there really is something beneficial about being cold.
So even when it’s frigid or snowy outside, there’s no excuse to avoid being outdoors.
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