Georgia: Brown fat tissue, the body’s “good fat,” communicates with the brain
through sensory nerves, possibly sharing information that is important
for fighting human obesity, such as how much fat we have and how much
fat we’ve lost, according to researchers at Georgia State University. The findings, published in The Journal of Neuroscience, help to describe the conversation that takes place between the brain and brown fat tissue while brown fat is generating heat.
Brown fat is considered “good fat” or “healthy fat” because it burns
calories to help generate heat for our bodies and expend energy, while
white fat stores energy for later and can increase the risk for health
issues, such as diabetes and heart disease. A person with a healthy
metabolism has less white fat and an active supply of brown fat.
Studies show that brown fat plays a big role in someone having the
capability to burn more energy, becoming a tool to stay trim and fight
obesity. Pharmaceutical companies are trying to target brown fat and
activate it more, said Johnny Garretson, study author and doctoral
student in the Neuroscience Institute and Center for Obesity Reversal at Georgia State.
The study found that when brown fat tissue was activated with a drug
that mimics the sympathetic nervous system messages that normally come
from the brain, the fat talked back to the brain by activating sensory
nerves. The sensory nerves from brown fat increased their activity in
response to direct chemical activation and heat generation.
“This is the first time that the function of sensory nerves from
brown fat has been examined,” Garretson said. “Brown fat is an active
organ that’s relatively important for metabolism, and we found a new
pathway of its communication.
“The study informs us more about the communication between fat and
the brain, which is really beneficial for treating human obesity. There
is evidence that people with more brown fat have a better metabolism,
lower instances of type II diabetes and are trimmer. Knowing how to
increase the amount of brown fat activity or increase the brown fat,
that’s the future of trying to figure out yet another way to try and
lose weight effectively and quickly.”
The researchers speculate that brown fat is telling the brain many
things, such as how much heat is being generated, how much and what
types of free energy are being used or stored, how much fat we have and
how much fat we’ve lost.
“As brown fat gets hotter and starts to generate heat, being active
and doing good things for our body, it increases our metabolism and
helps us burn white fat,” Garretson said. “As it’s getting hotter, Dr.
(Vitaly) Ryu and other members of our lab found that it tells the brain
it’s getting hotter. We think this is some type of feedback, like a
thermostat, and as it gets hotter, it probably controls how the brain is
talking back to it.”
It was already known the brain communicates with fat tissue by
telling it to break down and either release or use free energy for our
bodies to function. This study shows a feedback loop between brown fat
tissue and the brain.
The research team has studied the communication from fat to the brain
and the brain to fat for years, but they’re one of only a few labs in
the world to examine communication from fat to the brain through the
nervous system, Garretson said.
The research team includes Ryu, Garretson, Dr. Yang Liu, Dr. Cheryl
Vaughan and Dr. Timothy Bartness, director of the Center for Obesity
Reversal at Georgia State. The study is funded by the National
Institutes of Health.