Binge eating - defined as recurrent periods of excessive food consumption - is the most common eating disorder in the United States, estimated to affect around 3.5 percent of women and 2.5 percent of men.
Individuals who binge eat may report feeling a loss of control during food consumption, followed by feelings of guilt, shame, or distress. They often eat food more quickly than usual, and continue eating until they feel uncomfortable.
Because people who binge eat tend to choose unhealthy foods and rarely balance their excessive food intake with exercise, they are often overweight or obese.
Psychotherapy and cognitive behavioral therapy (CBT) are considered effective treatments for binge eating, and since depression is a cause of around 50 percent of binge eating cases, antidepressants may be beneficial for some people.
However, researchers may have now uncovered a way to prevent binge eating; they found blocking Trace Amine-Associated Receptor 1 (TAAR1) - known to bind to molecules called trace amines - stopped rats from compulsively eating junk food.
Study co-author Pietro Cottone, Ph.D., co-director of the Laboratory of Addictive Disorders (LAD) and associate professor of pharmacology and psychiatry at Boston University School of Medicine (BUSM), and team publish their results in the journal Neuropsychopharmacology.
TAAR1 agonist halting binge eating behaviors in rats
According to the researchers, previous studies have shown that TAAR1 agonists - compounds that directly activate the receptor - may reduce the behavioral effects of drug abuse.
For their study, Cottone and colleagues set out to determine whether a certain TAAR1 agonist - RO5256390 - might help reduce abnormal feeding behaviors in rats.
The team tested the compound on a rat model that they created to have binge eating-like behaviors.
Specifically, the rodents had an addiction to sugary, chocolate-flavored food. Compared with controls, the binge eating rats were more susceptible to cues associated with such foods, and they were even prepared to engage in risky behavior to obtain these foods.
The researchers found RO5256390 was able to block these binge eating behaviors; it dampened the consumption of sugary foods, inhibited cues associated with junk food, and stopped the rodents from entering an unsafe environment in order to retrieve sugary foods.
Commenting on what their findings show, the authors write:
"Altogether, these results provide evidence for TAAR1 agonism as a novel pharmacological treatment for compulsive, binge eating."
Investigation into the brains of the binge eating rats prior to receiving RO5256390 showed that, compared with controls, TAAR1 activity was reduced in their infralimbic cortex - a brain region that plays a role in decision-making and executive function.
According to co-first author Adam Howell, a master fellow in the LAD at BUSM, this suggests that TAAR1 acts as a "brake" in this brain region, curbing binge eating behavior.
"Subjects exposed to junk food lose this 'brake' and show aberrant addiction-like behavior over food. We are able to restore the function by activating this receptor," says Howell.
The Trace Amine-Associated Receptor 1 agonist RO5256390 blocks compulsive, binge-like eating in rats, Pietro Cottone et al., Neuropsychopharmacology, doi: 10.1038/npp.2016.233, published online 6 October 2016, abstract.
BUSM news release, accessed 7 October 2016 via EurekAlert.
Additional source: National Eating Disorders Association, Binge eating disorder, accessed 7 October 2016.