The three commonly encountered eating disorders include anorexia nervosa, bulimia nervosa and binge-eating disorder. These disorders are characterised by an over-concern over body image, body weight and also unhealthy eating habits or patterns. In anorexia nervosa people are very underweight as a result of extreme dieting, restrictive eating and/or excessive exercise.
People with bulimia nervosa have a ‘normal weight’ but have cycles of uncontrollable overeating. During this time, they consume huge amounts of food while feeling out of control and powerless to stop (bingeing), followed by making themselves sick after meals or abusing laxatives (purging) to make up for the food eaten.
In contrast, people with a binge-eating disorder have frequent episodes of uncontrollable binge eating but do not attempt to make up for the binges through vomiting, fasting, or over-exercising. Hormones that regulate metabolism, fertility, pregnancy, and bone health are particularly affected by disordered eating.
The hormonal changes in anorexia occur as a result of malnutrition. These include a fall in the concentration of sex hormones and thyroid hormones. These hormone levels return to normal when patients reach a normal weight. Anorexia can impact hormonal changes due to malnutrition and self-starvation. Concentrations of sexual and thyroid hormones will fall, possibly causing osteoporosis, or weakening of the bone, over time.
How does an eating disorder affect your body?
When an eating disorder begins in childhood or during the preteen years, the hormones that control puberty and growth will fail, leading to reduced development and maturation of bones. Puberty may be delayed and bones may fail to grow, leading to stunted growth and brittle bones (osteoporosis) later in life.
Damage to bone health cannot be reversed. The only way to prevent further bone damage is by treating eating disorders early and involves reversing malnutrition and increasing weight to a healthy level. Previously it was believed that hormone replacements such as the oral contraceptive pill would assist bone health in individuals with eating disorders. However, research has found that hormone replacement is insufficient to protect bone density. The only effective treatment for osteoporosis in anorexia nervosa is weight re-gain.
Eating disorders can also affect thyroid hormone levels, leading to hypothyroidism, which makes the individual feel cold easily, become constipated, or have very dry skin and other skin
Eating disorders can stimulate the production of the so-called ‘stress hormones’, which include cortisol, growth hormone and noradrenaline. These hormones are usually released in higher concentrations at periods of high stress and can lead to sleep problems, feelings of anxiety, depression and panic. Similarly, there is a strong physical response including an increase in heart rate and rate of breathing.
Our eating habits and weight have an important relationship with our hormones. In turn, hormones influence our overall growth and development, bone growth, puberty, fertility, level of alertness, sugar regulation and appetite. In eating disorders, the effects of unhealthy eating styles can influence hormone levels, causing physical and psychological problems.
Who is mainly affected by eating disorders?
Eating disorders mainly affect young people at what would otherwise be the peak of their reproductive lives. Unhealthy eating styles can lead to changes in reproductive hormones that are responsible for maintaining regular periods, sex drive, healthy hearts and strong bones. As a result, some women will have irregular periods, some will stop having them altogether and some may suffer infertility. Men, on the other hand, may lose their sex drive or have erectile problems. This is, again, the body’s response to try to save energy and prevent reproduction in a starving individual. Hormones return to normal levels once eating is back to normal.
Binge-eating disorder, compulsive overeating usually leads to obesity. Obesity causes an increase in hormone levels that encourages the build-up of body fat, thus making it even harder to lose weight.
