There are loads of reasons to limit the amount of fat in your diet, and a new study suggests there’s one more item to add to the list: A high-fat diet could impair your brain’s ability to regulate your calorie intake.
In tests on rats, scientists found that after prolonged high-fat, high-calorie diets, the signaling pathways between the brain and gut appear to be disrupted and no longer regulate calorie intake as it should.
Key to this signaling pathway are star-shaped cells in the brain, the so-called astrocyteswhich normally respond to high fat and calorie intake by slowing down and balancing out food intake.
“Over time, astrocytes appear to become desensitized to the high-fat diet,” says Kirsteen BrowningProfessor of Neuro and Behavioral Sciences at Penn State College of Medicine.
“[After] About 10-14 days after a high-fat/high-calorie diet, astrocytes appear to become unresponsive and the brain’s ability to regulate calorie intake appears to be lost.
This disrupts signal transmission to the stomach and delays its emptying.”
The rodents used in the research were divided into groups and fed a high-fat, high-calorie diet or a standard control diet for 1, 3, 5, or 14 days. In addition to recording food intake and body weight, the team also used genetic editing techniques to target and monitor specific neural circuits, including astrocytes.
By inhibiting astrocytes in the brainstem, the researchers were able to link these cells to reduced gut-brain communication and a lack of regulation of food intake that would normally occur during the first 3-5 days of a high-fat diet.
They found that inhibited astrocytes mimicked what happened to normal mice after a week or two on a high-fat diet.
It’s not yet certain exactly how astrocytes control what’s happening in the gut, but there’s clearly some kind of connection.
“We have yet to determine whether the loss of astrocyte activity and signaling mechanism is the cause of overeating or that it occurs in response to overeating,” says browning.
While the study only analyzed the eating habits of rats, there is good reason to believe that the same applies to humans. With obesity a serious public health problemprofessionals are looking for ways to better understand and manage them.
Obesity increases the risk of a whole range of health problems, including type 2 diabetescoronary artery disease, stroke and certain types of Cancer. It has also been linked to this depression and other mental problems.
The researchers hope that by discovering more about the “complex central mechanisms” behind the brain’s response to overeating, we’ll be able to devise ways to attack them and reduce obesity in the future.
“We are curious if it is possible to reactivate the brain’s apparently lost ability to regulate calorie intake. If so, it could lead to interventions that help restore calorie regulation in humans.” says browning.
The research was published in Journal of Physiology.
