Anorexia Nervosa: An Endocrine Problem?

By Rifka Schulman, MD

You’ve likely heard about eating disorders such as anorexia nervosa [a-no-REX-ee-uh nur-VOH-suh] or you might know someone who has anorexia. But did you know that people with anorexia are more than just “too skinny”? Actually, they also have problems with their hormone systems.


Anorexia nervosa is a serious eating disorder that affects about 1 in every 100 teenagers. It can lead to serious health problems, sometimes even death. How is a person with anorexia nervosa diagnosed? They have to have lost enough weight that they are less than 85% of expected body weight, and they have to have an intense fear of gaining weight, a disturbed body image (thinking you are fat when you really aren’t), and no menstrual period (in females) for at least three months.

Anorexia affects mostly women, but it can affect men as well. There are two major types: “restrictive” and “binge-purge.” The restrictive type means that the person eats very little and exercises too much. The binge-purge type means that the person overeats and then tries to remove the food or weight by vomiting, taking laxatives (pills causing diarrhea), or diuretics (pills making them urinate more).

About one-third of patients will completely recover, one-third will regain weight but still continue to have some of the prior eating behaviors, and one-third will remain sick for years.


Anorexia has very serious effects on many parts of the body. One common problem is abnormal electrolytes [ee-LECK-troh-lites] (sodium, potassium, etc.) in the blood. If they are very abnormal, it can lead to irregular heart rhythms and even death. Muscles can become weak all over the body, including the heart muscle. This is because of lack of protein. In people with anorexia the lungs can collapse, the gut can slow or get inflamed, the blood count can get too low, brain tissue can decrease, and the skin can change. All of this is because the person is starving himself or herself.


In addition to all of those harmful effects on the body, anorexia affects many aspects of the endocrine (hormone) system. The body reacts to the lack of nutrition by trying to conserve energy as much as possible. Through changes in hormone levels, only the most important functions of the body continue, while ones less important for survival shut off.


A prime example of what happens to the reproductive system in anorexic patients is that girls or women stop having their period. This is because the body knows that they can’t handle supporting a healthy baby. The severely low intake of calories sends a signal to the hypothalamus [hie-po-THAL-uh-mus], a small portion of the brain that controls many other endocrine glands. This signal leads to less hormones coming from the pituitary [pih-TOO-ih-tare-ee] gland in the brain, which would normally cause a woman to ovulate [AH-vyoo-late] and get her period each month.

Men with anorexia also can have problems with their reproductive system. It may not be as obvious as in women. These men will commonly have a low testosterone [pronunciation] level (which is also because the body is shutting down reproduction), and they may lose interest in sex and have trouble having an erection.


The thyroid gland is also affected when a person starves themself. Normally, the thyroid produces a hormone called T4 which is converted to T3, the active hormone, when circulating throughout the body. TSH, a hormone produced in the pituitary gland, stimulates the thyroid to produce T4 as needed. Any severe illness, including anorexia, prevents T4 from converting to T3. If there is a severe lack of T3, the heart rate and metabolism may slow, and body temperature may decrease below normal. In addition to a low T3, TSH and T4 may decrease in patients with anorexia.


Osteoporosis [ah-stee-oh-pore-OH-sis], a problem of low bone density that puts the person at increased risk of fracture, is a common side effect of anorexia and can last for many years. The bones of a teenager with anorexia can be weaker than those of an old man or woman! This happens for several reasons. Many of the abnormal hormone levels mentioned above contribute to bone loss. Bone loss is linked to low estrogen, which results from the reproductive system “shutting down.” Poor nutrition also leads to decreased intake of calcium and vitamin D, which are necessary for bone health. In teenagers the bone loss is happening at a time when bone should be growing instead of shrinking. All of these factors lead to low bone mass which makes the person more at risk for fracture.


The good news is that despite all the medical and endocrine problems that can develop due to anorexia, many of them can be cured by fixing the underlying eating disorder and gaining weight. A team approach is often needed, such as a psychiatrist [sye-KYE-uh-trist] or psychologist [sye-KAH-low-jist], an endocrinologist [en-doh-cri-NA-lo-jist], and other health professionals. Knowing about the dangers of eating disorders is important because preventing anorexia will prevent so many other problems. EmPower yourself with knowledge.

Dr. Schulman is a clinical fellow in the division of Endocrinology at Mount Sinai School of Medicine, NY. During the course of her training she has had the opportunity to care for several patients with severe anorexia nervosa and help manage their nutritional status and endocrine abnormalities.