Did you know that people have brown fat? I didn’t — until recently. I knew that bears, squirrels, winter birds and other wildlife do to survive the cold — but people?
Brown fat (AKA brown adipose tissue) helps maintain your body temperature when you get too cold. It’s the same fat that bears have to stay warm when they hibernate and then gives them energy to rewarm out of hibernation. Brown fat works the same way for mammals, like squirrels, that go into torpor (a mini-hibernation) when it’s dangerously cold.
Brown fat acts as a built-in heater. Human babies are born with brown fat on their upper backs. You lose most of it as you get older and then form a shiver response to cold temperatures. Although you lose most of your brown fat as you grow, you may hold on to some of it. Some adults have small amounts of brown fat around the shoulders, neck, collarbone, kidneys and spinal cord. Lean people typically have more brown fat than overweight people. Women also tend to have more than men.
You also have another type of fat — white fat which is different. White fat builds up when you take in extra calories storing it to use when you don’t get enough energy from food. It’s made of big droplets of lipids, or fatty acids. Most of the fat in your body is white fat; typically stored in your thighs, hips and waistline. Too much white fat in your belly can raise your risk of heart disease and Type 2 diabetes.
But, cells in brown fat are packed with iron-rich mitochondria giving brown fat its colour. They take in nutrients like sugar and white fat and break them down to make energy. Brown fat stores more energy in a smaller space than white fat does. When your body gets cold it signals the mitochondria to start churning out energy. This creates the warmth that helps you maintain your body temperature. It creates heat without shivering and burns calories. Brown fat may decrease obesity and some metabolic problems.
All people have some “constitutive” brown fat which they’re born with. There’s also “recruitable” brown fat formed under the right circumstances. Here’s how:
Turn the temperature down and go for winter walks
Exposing yourself to cool and even cold temperatures may help recruit brown fat. Just two hours of exposure each day to temperatures around 19 degrees Celsius may be enough to gain recruitable brown fat. Consider taking a cold shower or bath. During winter, turn the thermostat down a few degrees in your home and go outside in cold weather to cool down.
Brown fat burns calories and helps you stay leaner and healthier. A well-balanced diet of healthy unprocessed foods certainly helps too.
Exercise may signal hormones that create brown fat. Exercise fights obesity, keeps the cardiovascular system running strong and has so many other health benefits. Do a minimum of one of the following every week:
• 150 minutes of moderate activity, such as walking
• 75 minutes of vigorous activity, such as cross country skiing
So they say. Keeping cool at night helps recruit brown fat.
Brown fat research
Researchers know that brown fat burns calories and may help control blood sugar, improve insulin levels and may also help remove fats from blood. Most brown fat studies have been done on mice. More research is needed on people.
Roseanne Van Ee enthusiastically shares her knowledge of the outdoors to help readers experience and enjoy nature. Follow her on Facebook