Posted on: September 6, 2007
How Brown is Your Fat?
Recent studies show a possible link between brown fat cells and reversing obesity. What is the difference between brown and white fat cells, and what, if anything, can brown do for you?
By Anna T. Hirsh
CTW Features
A fat cell is a fat cell for life. Once one appears in your body, it rarely if ever goes away. It simply grows or shrinks depending on your weight. But have you ever considered the fact that the actual color of your fat might help dictate what that weight is?
There are two main types of fat cells in the body: white and brown. When we think of fat cells, the ones that make our thighs dimple or our bellies bounce, are usually the white version. “White fat cells function to store energy,” says Bruce M. Spiegelman, Ph.D., professor of cell biology at the Dana-Farber Cancer Institute, Harvard Medical School, Boston. “Brown cells dissipate energy by oxidizing fuels to make heat.”
What this means is that white fat cells are designed to hold energy for use in times of need, but brown fat cells actually burn energy (or calories). In humans, brown fat cells are mostly found in the neck area of newborns because infants regulate body temperature far less efficiently than do adults. These cells largely disappear by adulthood, but their precursors still remain in the body, holed-up in white-fat depots.
In laboratory experiments, however, at the Joslin Diabetes Center and Children’s Hospital Boston, Boston, in 2005, scientists discovered a group of genes in mice that create calorie-burning brown fat cells. Researchers theorized that finding ways to encourage the development of brown fat might be good for treating obesity.
In his more recent experiments with mice, Spiegelman and his fellow Dana-Farber researchers inserted a gene/protein called PRDM16 into precursors of white fat, and then implanted those precursors under the skin of the animals. The PRDM16 triggered those cells to generate brown fat cells, essentially making what would have been fat storage into a fat incinerator.
Spiegelman and his colleagues have continued this research, and says that he hopes scientists will be able to manipulate brown fat cells to make them helpful to adult humans in the near future. “But we have not been successful yet…Maybe transplantation, someday,” he says. If you want to avoid obesity and related illnesses now, he says, “just eat less and exercise more.”
This practical “antidote” is exactly the same as that prescribed by Marilyn Tanner-Blasiar, a spokeswoman for the American Dietetic Association, Chicago, and a pediatric dietitian at the Washington University School of Medicine, St. Louis. “Exercise, diet and behavior are the first approach to weight management,” she says.
One of the major factors of causation for the United States’ current obesity epidemic, she says, is that people are getting far less exercise than they used to and “more screen time.” She says, “before, if you didn’t like what was on the major networks, the television would be off. But now you just change channels and keep sitting.” She also points to computer usage, gaming and DVDs. “Just move,” Tanner-Blasiar says. “Walk. Find something you like, and do it!”
And, of course, eat right. Tanner-Blasiar recommends eating more low-fat dairy, lean protein, fruits and veggies (not fried or dipped in sauces), drinking more water and calorie-free beverages, increasing your consumption of whole grains and watching the fat content in the foods you select because the calories add up fast. “Fuel your body regularly,” she adds. “Breakfast, lunch, snack, supper, snack. This way you don’t have to think constantly about food because you know more is coming.”
When it comes to other currently available means of combating obesity, “surgery and medications are only a small part of the solution,” Tanner-Blasiar says. “Although many people get quick and notable results with surgery, the individuals that have surgery still have to modify their lifestyle. The foods they eat need to be even more nutrient-dense and pack more power.” After stomach-stapling, for instance, the appetite is smaller, but so is one’s ability to take in necessary nutrients so food choices need to be smarter.
This isn’t to say that Tanner-Blasiar isn’t open to the new, cutting-edge studies. “As far as technologies that will help combat fat and help those who struggle with obesity,” Tanner-Blasiar says, “I think we will all benefit from the research regarding white and brown fat cells, to help us better understand the best way to combat the fat, to prevent future gain and even to try to eliminate it.”
For now, however, if you want to take a bite out of your bulge, leave the brown fat to the scientists and look to brown rice instead.
