There’s More to Body Fat Than You Might Think
Body fat isn’t just an inert blob; it’s alive and like a major organ, communicates with the brain.
When Michael Goran, co-director of the USC Diabetes and Obesity Research Institute, started studying obesity 30 years ago, scientists thought body fat was inert and simply served as a way to store potential energy for the body. Since then, science has shown that our body fat isnt just a blob.
Body fat operates like a major organ: It releases hormones and other substances, has a blood supply and nerves and communicates with the brainjust as we think of, say, the pancreas. Goran, a professor of preventative medicine and pediatrics, calls this concept of fat a breakthrough in a field with no hope of a miracle pill.
Scientists are rapidly identifying the substances that body fat releases and why they matter. For example, theyve found that fat pumps out chemicals called cytokines that stoke the immune system and promote inflammation, raising blood pressure and causing other health problems. It also releases a hormone called leptin that can quell appetite and another called adiponectin that helps control blood sugar. And thats just for starters.
Theres another factor: USC researchers have shown that fat tucked between abdominal organs like the stomach and liver is more dangerous than fat deposited just under the skin. Deep belly fat emits more of the hormones, fatty acids and other substances that cause harm. But whyand why fat ends up in one place rather than the otherremains a mystery.
At the USC Dornsife College of Letters, Arts and Sciences, scientists are focusing not just on the gut, but also on another key spotthe brain.
Alan Watts, USC professor of biological sciences, physiology and biophysics, seeks answers in the hypothalamus, a master controller in the brain for how and why we eat and drink. And his colleague Scott Kanoski, an assistant professor of biological sciences, is researching the neurobiology behind compulsive overeating. Once scientists drill into the science of bingeing, they can come up with solutions.
One promising target lies in sugar, and how it affects the brain. In studies of rats, Kanoski and Goran found that animals that consumed high fructose corn syrupthe cheap sweetener in sodahad more trouble with spatial learning and memory (how effectively they navigated a maze) than those that consumed sucrose, or ordinary table sugar. Both groups performed worse than rats that just drank water.
And seeing differences in how the sugars fructose and glucose are metabolized is what Keck School of Medicine endocrinologist Katie Page 94, MD 02 calls one of the most exciting and provocative findings coming out of her recent work.
Although the two sugars offer the same calories, glucose has some beneficial effects, like working with hormones in the gut to make people feel satisfied so they stop eating. Fructose, though, fails to stifle hunger.
Weve only looked at fructose and glucose by themselves, Page says. The next step is seeing what happens in the brain when fructose and glucose are consumed togetheras theyre found in table sugar or soda. (See Katie Pages tips on sugar at bit.ly/KatiePage).