Research finds cold fat releases calorie-burning energy

Kathleen Blanchard's picture
White fat releases energy in response to cold, finds Harvard researcher.
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Harvard researchers have made a discovery about how the body burns white fat that lingers in the body and seems impossible to eliminate. According to their findings, fat releases energy that could burn calories when it is exposed to cold. The finding means manipulating fat could be used as an obesity treatment.

Cold fat burns more calories

The way it works is simple. Fat burns more calories when it is cold to stay warm, the scientists found. The hope is that the discovery could lead to new treatments for obesity and type-2 diabetes.

Previous studies have shown the body releases brown fat cells in response to cold temperatures. The assumption was the response was and indirect result of stress.

Dr. Bruce M. Spiegelman, Harvard Medical School discovered in 2009 that the body's brown fat cells causes white fat to break down to generate heat as a protective mechanism. Spiegelman has been studying fat for decades in hopes of finding new treatments for obesity. He subsequently created brown fat in mice that turns into muscle.

In the previous study, he found the protein UPC1 is needed to activate the fat-burning process that sends signals to the brain to release norepinephrine in response to stress.

The researchers also found mice lacking norepinephrine receptors were able to still turn on UPC1 in the current experiment.

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Spiegelman has discovered activation of brown fat isn't just a stress response and that white fat - the kind that stores in the abdomen and raises risk of heart disease and diabetes - also responds to cold by releasing heat that burns calories.

In the new study published July 1, 2013 in Proceedings of the National Academy of Sciences, Spiegelman accidentally found white fat behaves the same as brown fat when subjected to cold temperatures.

For their study, the research team placed three mixtures of human fat cells in cold storage anywhere from 4 hours to up to 10 days - white, brown and 'beige' (a combination of brown and white fat).

Fat was stored at temperatures between 27 and 39 degrees centigrade.

Fat-manipulating pills in the future?

After the researches removed the cells from the cold they discovered UPC1 had nearly doubled after just 8 hours in the white and beige fat cells. The protein level was reversed again when the fat was cooled to 37 degrees.

It may be possible to turn fat into calorie-burning machines by manipulating their behavior. "It's a piece of the basic science, adding to an evolving awareness that fat cells have many lives that we never knew about. Now we know they can sense temperature directly. The next question is, how do they do it, and can that ability be manipulated?"

The finding shows fat cells are very adaptable and that white and brown fat both respond to cold temperatures by burning calories, but through a different mechanism than previously known. It may indeed be possible to use fat, which is the very thing we all struggle to fight, as a treatment for obesity. Spiegelman says there is no "antifat" pill in the immediate horizon, but the study paves the way for further exploration.

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