Binge eating disorder is reported to be experienced by more women than men. In the U.S. alone, men diagnosed with the disorder account for only 2% (3.1 million) of the population as opposed to 3.5% for women (5.6 million). Additionally, two-thirds of people in the U.S. with binge eating disorder are obese. Individuals with this condition may risk having high blood pressure, type 2 diabetes, arthritis, cancer, and heart disease later in life.
Overview of binge eating disorder
Binge eating is the frequent consumption of large quantities of food (often quickly and while feeling uncomfortable) and at short time intervals (every two hours). Loss of control usually emerges from a feeling of shame and guilt. Due to the emotional dependence of food, unhealthy habits like purging may occur.
Myelin sheaths in the brain
Signals from the brain are transmitted through electrical signals by nerve fibers. These fibers are further insulated by a white fatty substance composed of lipids and proteins, known as the myelin sheath. In the Central Nervous System, which includes the spinal cord and brain, myelin is referred to as oligodendrocytes. The term myelin sheath takes the form of wrapped branch extensions around the axons.
Role of myelin sheaths in behaviour and cognition
The human brain develops significantly between the ages of ten to twelve years old. A study on 111 children displayed the relationship between brain composition and different developmental stages. There was a correlation between the density of white mater in fiber tracts within the frontotemporal and corticospinal pathways – suggesting gradual maturation that support speech and motor functions.
A study from Romanian institutions on seven children adopted into families in the U.S. demonstrated variation in myelin composition among normally raised kids and adopted children. In the latter, there was less white matter in the brain in the uncinate fasciculus, especially the amygdala, which is responsible for connecting temporal lobe and prefrontal cortex. The amygdala regulates memory and emotional reactions, while the prefrontal cortex plays a role in decision making and social interaction.
Myeling sheaths and binge eating
Researchers from Boston University School of Medicine (BUSM) used gene mapping and gene validation to identify cytoplasmic FMR1-interacting protein 2 (CYFIP2) as a significant influence for binge eating. Camron D. Bryant, an assistant professor of pharmacology and psychiatry at BUSM, Laboratory of Addiction Genetics, predicted that there are genes responsible for eating disorders and some addictions.
Mice were studied for their behavior with addiction to alcohol and psychostimulants. After breeding across generations, their offspring displayed connections between genetic inheritance and behavioral variation – precisely, their eating behaviours. Additionally, co-author and assistant professor at the Jackson Laboratory – an independent biomedical research – found a predictor of cocaine addiction in the same chromosol region. Both investigations pointed to the mutation of the CYFIP2.
Binge eating was associated with a decrease in the production of particular genes in the striatum, the brain’s reward system. This gene plays a role in forming myelin sheaths. Decreased myelination is not a factor that represents binge-eating; but rather, a by-product of repeated binge eating behaviour.
A plausible solution is the restoration of myelin in those areas of the brain in individuals that exhibit binge-eating disorder. Further research will involve reversing behaviours associated with binge eating such as anxiety, depression, compulsivity by administering treatments that promote remyelinating and restoring neuronal function.
Although results suggest inducing myelination as a treatment for poor feeding behaviours in eating disorders, it is important to consider the possible detrimental effects. Perhaps other pathways may be indirectly affected. Will treatment on humans have the same outcome observed in mice?