High-calorie foods are known to be addictive, which means it is hard to just eat a regular amount of oil, sugar, and fat without overeating. And while they taste good, overindulging may lead to health problems such as obesity. But now, scientists have discovered that one of the causes of this behaviour might be a genetic predisposition.
The genetic switch responsible for binge eating was recently discovered by research conducted at Osaka Metropolitan University and published in The Faseb Journal.
Previous studies already found that people with genetic mutations of MC4R — a regulator of food intake — are prone to becoming obese and developing type 2 diabetes. The latest research now shows that CRTC1 deficiency, a protein-coding gene, when particularly present in MC4R cells, induces obesity, hyperphagia (an uncontrolled hunger), and insulin resistance.
“Here, we demonstrate that mice lacking CRTC1, specifically in MC4R cells, are sensitive to high-fat diet (HFD)-induced obesity and exhibit hyperphagia and increased body weight gain,” the research states.
In the experiment, only the mice that received a high-fat diet developed the traits, while those that were fed a normal diet did not show any changes in their metabolism.
The research, therefore, concluded that the gene CRTC1, when expressed in MC4R cells, “is required for metabolic adaptation to HFD concerning appetite regulation.”
“We hope this will lead to a better understanding of what causes people to overeat,” said Shigenobu Matsumura, who led the study.
Binge-eating disorder, also known as BED, is among the most common eating disorders worldwide. It is characterised by an urge to eat unusually large amounts of food, even without being hungry. Since 2013, the Diagnostic and Statistical Manual of Mental Disorders has recognised BED as an eating disorder diagnosis, and as such, it is possible to receive treatment and recover from it.
The recent research at Osaka Metropolitan University is not the only one trying to shed light on this eating pattern. For many years, scientists have conducted experiments to understand what causes a desire to overeat in certain people.
Some research shows that compulsively consuming high-calorie foods can cause a type of addiction similar to the one caused by cocaine or heroin. Evidence shows that engaging in this type of diet creates a dysfunction in the brain’s reward system: the more we eat, the more dopamine the brain releases.
This dopamine boost is often one of the biological reasons why some people overindulge, and it is particularly true for those affected by other conditions such as depression, who might seek this eating pattern as a way to improve their mood.
But more recently last month, another study published in Nature Neuroscience uncovered another reason for maladaptive eating disorders, such as binge eating, and this time it was not related to dopamine levels or gene mutations.
A Virginia Tech scientist, Sora Shin, is the first to have discovered a possible link between early life trauma and binge eating. To do so, Shin and the rest of her lab team studied the impact of leptin, a hormone responsible for regulating hunger as well as the balance between food intake and body weight.
The team then experimented on mice and found that in those that presented early life stress and binge-eating patterns, leptin was less effective in giving the signals to regulate the urge to eat.
The potential for this discovery is significant because, for the first time, the cause behind maladaptive eating patterns, such as binge eating, can be attributed to traumatic experiences that alter a certain brain circuit.
“We are increasingly aware that early experiences and exposures ranging from those that occur even pre-conception in future parents through those that the fetus experiences in utero and those that the child experiences throughout postnatal life can have a dramatic impact on our health course throughout life,” said Michael Friedlander, Virginia Tech’s vice president for health sciences and technology.
Whether causes are attributed to traumatic experiences or biological factors, the recent boost in studies of the drivers of obesity and overeating is certainly a good starting point for trying to tackle these disorders, which continue to affect a huge amount of the population globally.
“There is much more research to do,” Shin said, “but by knowing the specific molecules and receptors in the brain to target, we can now provide insight and the foundation for developing therapeutic strategies for the disorder.”
Photo credit: Szabo Viktor on Unsplash
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