The Science Behind Eating Disorders
Most people, including me, would associate eating disorders with cultural and social pressures, that only external factors are the cause of severe disorders such as anorexia and bulimia. Misinformation is extremely common surrounding eating disorders. While the environment certainly does play a big role in the development of these disorders, there is recent evidence proving that the brain itself plays a big role.
First off, eating disorders are any illness that causes serious disturbances to one's diet. The most commonly known are Anorexia Nervosa, extreme food restriction and emaciation, and Bulimia Nervosa, episodes of binge eating followed by purging, fasting, or excessive exercise.
Both of these can cause severe illnesses such as gastrointestinal problems, electrolyte imbalance and cardiovascular disease,muscle wasting, heart and brain damage, and multi-organ failure.
These dangerously maladaptive approaches to food literally causes the diagnosed to starve themselves to death, and this is why it's so important to realize the true causes of eating disorders. Doctors can't properly treat unless they know the correct cause.
A faulty reward-processing system is common within those diagnosed with an eating disorder. Learning from rewards is an ancient ability of humans, and this process is highly common with the growth of eating behaviors. For example, whenever you eat chocolate cake, we're rewarded with the pleasurable taste, and we want to take another.
However, there's an altered balance in people with anorexia where they have difficulty coding reward, and they're oversensitive to punishment.
The cause of this might be related to dopamine, the neurotransmitter which plays a major role in the motivational component of reward-motivated behavior. Dopamine tells us to cut another slice of that chocolate cake. Dopamine activity is altered in those with anorexia and bulimia, but it works in the opposite way. When they sit down to eat, it makes them worried and anxious. In people with anorexia, the release of dopamine in the dorsal striatum (brain area associated with habitual behavior) triggers anxiety instead of pleasure.
Scientists have also identified several brain regions that could also be the cause of eating disorders. One of these is orbitofrontal cortex, which is involved in signaling us when to stop eating. Research has found structural differences in those with anorexia and bulimia in these areas.
Another structure is the right insula, which processes taste sensations, but it's also involved in interoception, the ability to sense one's own bodily signals. People with eating disorders have been found to be extremely hypersensitive to changing body sensations, and extreme food restriction might be a coping mechanism to this hypersensitivity. In response to this starvation, the body slows down; the heart rate declines, menstrual cycles stop.
To test this idea, scientists scanned the brains of healthy women and women who had been treated for anorexia as they focused on sensations in their hearts, stomachs or bladders. They found abnormal insula activity in the women with anorexia. Interestingly, a particular subregion of the insula also showed increased activity when the women with anorexia were asked to think about situations that worried them. That finding suggests that altered interoception might contribute to their anxious temperament.
There's a lot more to learn about the neurobiology portion of eating illnesses, but in the meantime,scientists and doctors work together and try their best to treat and prevent these horrible disorders.
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