Hormonal Disturbances and Bulimia

Bulimia, more accurately called bulimia nervosa, is an eating disorder that was first described by  Professor Gerald Russell in 1977 whilst he worked at the Royal Free Hospital,in London in 1977.

There are five criteria that have to be met for someone to be diagnosed with bulimia nervosa:

1. Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:
• Eating, in a discrete period of time (e.g., within any two-hour period), an amount of food that is definitely larger than most people would eat during a similar period of time and under similar circumstances.
• A sense of lack of control over eating during the episode (e.g., a feeling that one cannot stop eating or control what or how much one is eating).
2. Recurrent inappropriate compensatory behavior in order to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics or other medications; fasting; or excessive exercise.
3. The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice a week for three months.
4. Self-evaluation is unduly influenced by body shape and weight.
5. The disturbance does not occur exclusively during episodes of anorexia nervosa.

It has long been known that there can be a number of hormonal disturbances in people with both anorexia nervosa and bulimia, but it has never been clear whether they are a result of malnutrition, vomiting and/or the use of laxatives and diuretics. When we were both at the Maudsley Hospital in London, Gerald and I once spent several hours talking through the possibilities of doing some collaborative work on the hormonal problems in people with eating disorders. The list of disturbances was so long that we decided that we had other priorities.

So I am fascinated to see some new research from the Karolinska Hospital in Stockholm.

Amongst the most prominent problems in people with bulimia are menstrual irregularities and increased rates of polycystic ovarian syndrome (PCOS). A Dr Sabine Naessén studied 77 women with bulimia and 59 healthy volunteers.

As expected the women with bulimia had higher rates of menstrual disturbances, hirsutism and PCOS. And in line with previous research, levels of testosterone correlated with amounts of hirsutism.

The women with bulimia also had lower bone density, particularly if their menstrual cycles had stopped or if they had ever had anorexia nervosa.

She also found an association between two common polymorphisms in the estrogen receptor (ER) β gene and bulimia. She has speculated that this genetic variation might predispose women to the development of bulimia.

Her results suggest that some women with the condition may have too much of the male hormone testosterone. Half of the people treated for this imbalance reported less hunger, and fewer cravings for fatty and sugary foods.

This is important work. It is highly unlikely that eating disorders could ever be reduced to biochemical disturbances in the brain. There are so many environmental factors, for instance sexual abuse or other types of trauma, and even social pressure, that have been implicated in the etiology of the illness.

But the key point is this: why do some people develop an eating disorder after trauma while other do not? And why do some people develop eating disorders, even when they have never been traumatized in their lives?

The answer as always lies in the ways in which genes and the environment interact. If confirmed, this research may point the way toward some new ways of helping some people with this group of illnesses.