By Dr Ananya Mandal, MD
There is no single cause for eating disorders. The basic tenet of eating disorders seems to be concerns about weight and body shape. There are many factors, including cultural, familial, and emotional and personality factors as well as genetic and biologic factors that may play a role in causation of eating disorders.
Some of the factors that influence eating disorders and its causation include:
Negative influences within the family can trigger and maintain eating disorders.
Poor parenting attitudes and behaviors may be a primary cause. Poor parenting by both mothers and fathers has been implicated in eating disorders. Often if one of the parents, especially the mothers, had a history of eating disorders, the child is likely to develop them. Paternal criticism of weight can lead to bingeing and purging in young males, studies show. Family history of obesity in one or both parents may also be a trigger for bulimia.
History of addictions in the family and other emotional disorders also influences young children. People with either anorexia or bulimia are more likely to have parents with alcoholism or substance abuse than are those in the general population. In addition, those with bulimia are more likely to have parents with psychiatric disorders.
History of abuse is another common triggering factor. Bulimia seems to have a positive link with early sexual abuse. History of being teased or ridiculed for size or weight is another important trigger.
While obesity is a global epidemic, attitude to food is different in different cultures and often triggers one of the eating disorders. Media influences and pressures on being thin and the overproduction of food both likely play major roles in triggering obesity and eating disorders.
While advertisers are marketing weight-reduction programs and showcasing anorexic young models as sexually desirable, most clothes are designed and displayed for thin bodies and on the other hand there is severe criticism towards consuming “junk” food. The influences are confusing especially for the young.
Most of the eating disorders run in families. Anorexia is eight times more common in people who have relatives with the disorder. Twins also seem to have a tendency to share specific eating disorders (anorexia nervosa, bulimia nervosa, and obesity).
Some studies have linked regions on chromosome 10 to bulimia as well as obesity. Researchers suggest that genes may determine the interplay of neurotransmitters like serotonin, the brain chemical involved with both well-being and appetite. Researchers have found certain proteins such as brain-derived neurotrophic factor (BDNF). This protein may influence an individual's susceptibility to developing an eating disorder.
Usually there may be disturbances in thyroid hormone production among those with eating disorders. Eating disorders are also linked to stress, well-being, and appetite. Many of these chemical changes are certainly a result of malnutrition or other aspects of eating disorders.
The problem often arises in the limbic system of the brain. A specific system called hypothalamic-pituitary-adrenal axis (HPA) may be particularly important in eating disorders. It involves the hypothalamus that controls among other things, eating, sleeping, and regulates body temperature and emotions along with regulation of secretion of hormones.
The HPA axis also involves the pituitary gland that controls thyroid functions, the adrenal glands, growth, and sexual maturation. The third important part of the axis is the amygdale. This is a small almond-shaped structure lies deep in the brain and is associated with regulation and control of major emotional activities, including anxiety, depression etc.
The HPA systems trigger the production and release of stress hormones called glucocorticoids, including the primary stress hormone cortisol. Prolonged high levels of stress chemicals have been observed in patients with anorexia and bulimia. The HPA system also releases certain neurotransmitters that regulate stress, mood, and appetite.
Another important trigger is ghrelin, a hormone that increases the feeling of hunger and slows metabolism. Increased ghrelin is noted in patients with anorexia and bulimia. The HPA system is also responsible for the production of important reproductive hormones that are severely reduced in anorexics.
Psychological and biological Factors include:
Feelings of inadequacy
Feeling the lack of control in life
Difficulty expressing emotions and feelings
Some personality types like obsessive-compulsive and sensitive-avoidant are more at risk
Certain genetic factors predispose some people to anxiety, perfectionism, and obsessive-compulsive thoughts and behaviors. These persons are at a greater risk of eating disorders.
People with eating disorders tend to be perfectionistic. They tend to have an unrealistic expectation of themselves and others.
Eating disorders may be triggered to avoid sexuality.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)