What is anorexia nervosa?

Anorexia nervosa is a life-threatening eating disorder. It is defined as self-starvation in order to maintain an abnormally low body weight. Low body weight is described as weighing less than the minimum that is considered normal for the person’s age, sex, stage of growth and development, and physical health. Individuals with anorexia nervosa have an intense fear of gaining weight or becoming fat and have a distorted self-image of their body weight and shape. Extreme weight loss in people with anorexia nervosa can lead to dangerous health problems and even death.

Who gets anorexia nervosa?

Anorexia nervosa can occur in people of any age, sex, race, gender, ethnicity, economic status, as well as individuals of all body weights, shapes and sizes. Anorexia nervosa is most commonly seen in adolescents and young adult females, although it also occurs in males and is increasing in numbers in children and older adults.

What are the health harms of anorexia nervosa?

Not getting enough nutrients (malnutrition) and starvation affects nearly every system of the body.

  • Effects on the heart. Slow heart rate (bradycardia), low blood pressure (hypotension) and orthostatic hypotension are common effects of starvation. These complications increase the risk of ventricular arrhythmia and sudden cardiac death. The heart itself can lose some of its muscle mass, which can lead to mitral valve prolapse.
  • Effects on the brain. Starvation affects the brain’s structure – including decreased brain tissue and brain activity and function. Functions impaired include decision making, ability to concentrate/focus, memory issues, emotional control, appetite regulation, mood and reward pathways.
  • Effects on the digestive tract. Starvation can cause abdominal discomfort and pain, bloating, constipation, feelings of being full, as well as lead to fatty liver disease (steatosis).
  • Effects on the body’s hormones. Starvation can cause missed menstrual periods (amenorrhea) and reduced levels of female hormones, low testosterone levels, delayed puberty and physical growth, underactive thyroid (hypothyroidism), euthyroid sick syndrome, and in older individuals, increased the risk of weak bones (osteopenia), bone loss (osteoporosis) and stress fractures.
  • Effects on the body from vomiting (purging). Exposure to stomach acid can wear down the enamel on teeth and enlarge the salivary glands. Loss of water and electrolyte/acid-base imbalances can cause a loss of potassium and lead to rhabdomyolysis (damaged skeletal muscle) and kidney damage.

Many of these complications can improve and be reversed as weight is regained. However, if anorexia nervosa has been ongoing for years, bone loss, physical growth, and structural brain changes may not fully recover.

What are the symptoms and behaviors of people with anorexia nervosa?

Physical signs and symptoms include:

  • Significant weight loss over several weeks or months
  • Unexplained change in growth curve or body mass index (in still growing child/adolescent)
  • Feeling tired
  • Slow or irregular heart beat
  • Sleep problems
  • Poor concentration/focus
  • Memory loss
  • Feeling cold all the time
  • Dizziness
  • Fainting
  • Absent or irregular menstrual periods
  • Chest pain, heart palpitations
  • Low blood pressure (hypotension)
  • Shortness of breath
  • Swelling (edema)
  • Swelling in the neck area
  • Dental cavities, erosion of tooth enamel
  • Bloating, abdominal pain or discomfort
  • Blood in vomit
  • Heartburn (gastroesophageal reflux)
  • Constipation
  • Hemorrhoids
  • Muscle weakness, loss of muscle mass
  • Dry skin, brittle nails, hair loss/thinning hair, growth of fine hair on the body (lanugo)
  • Poor wound healing
  • Bluish or purple coloring of the hands and feet

Emotional and behavioral symptoms include:

  • Binge eating or purging behavior
  • Continuing to diet even when thin or when weight is very low
  • Having an unusual interest in food, calories, fat grams and dieting
  • Sudden change in eating behavior – becoming a vegetarian/vegan; interest in certain food types or certain food groups, or eliminating certain food types or food groups
  • Intense fear of gaining weight
  • Strange eating habits or routines, such as eating in secret, eating foods in a certain order, rearranging foods on a plate
  • Feeling fat, even if underweight
  • Inability to realistically assess one’s own body weight
  • Striving for perfection and being very self-critical
  • Undue influence of body weight or shape on self-esteem
  • Depression, anxiety, or irritability
  • Obsessive/compulsive symptoms and behaviors
  • Infrequent or irregular menstrual periods in females
  • Laxative, diuretic, diet pill or appetite suppressants, or enema use
  • Purposely not taking insulin (in people who have diabetes) to lose weight
  • Frequent illness
  • Wearing loose clothing to hide weight loss
  • Compulsive exercising or extreme physical training
  • Feeling worthless or hopeless
  • Withdrawal from friends and social events
  • Inability to describe one’s emotions
  • Doesn’t enjoy life; thoughts of self-harm or suicide

What causes anorexia nervosa?

The exact cause of anorexia nervosa is not known, but research suggests that a combination of certain personality traits, emotions and thinking patterns, as well as biological and environmental factors might be responsible.

People with anorexia nervosa may use food and eating/not eating as a way to gain a sense of control when other areas of their lives are very stressful or when they feel overwhelmed. Feelings of inadequacy, low self-esteem, anxiety, anger, or loneliness also might contribute to the development of the disorder. In addition, people with eating disorders might have troubled relationships or have a history of being teased about their size or weight. Pressure from peers and a society that equates thinness and physical appearance with beauty also can have an impact on the development of anorexia nervosa.

There is no single path to an eating disorder. For many, irregular eating behaviors (also called “disordered eating”) represents an inappropriate (doctors may say, “maladaptive”) coping strategy that becomes permanent over time. This pathway to disordered eating is true for some, but not all, who develop this set of illnesses.

Eating disorders also might have physical causes. Changes in hormones that control how the body and mind maintain mood, appetite, thinking, and memory might foster eating disorders. The fact that anorexia nervosa tends to run in families also suggests that a susceptibility to the disorder might be inherited.

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