8 Medical Complications of Anorexia

Anorexia nervosa (AN) is one of the most prevalent eating disorders in the United States, affecting individuals of all ages, races, and genders.

Unfortunately, it’s also one of the most dangerous eating disorders, associated with numerous medical comorbidities, or co-occurring conditions, and an overall increased mortality risk. [1]

And while anorexia nervosa is counted among mental health disorders, the significant impact the condition has on the physical body can lead to a number of severe medical complications, which can further complicate the recovery process for those struggling with this condition.

What is Anorexia Nervosa?

Anorexia nervosa is a serious mental health disorder, characterized by a distorted body image and an extreme fear of or aversion to gaining weight.

The condition can manifest in a number of ways, including extreme exercise, self-induced vomiting, or other maladaptive attempts at weight control. But most frequently, it appears as extreme restriction of food intake, leading to dangerous weight loss and malnourishment.

There is likely no one cause of AN, but rather a variety of factors that combine in certain individuals to produce these disordered thoughts and behaviors. Indeed, a number of genetic, psychological, and environmental considerations have all been linked to the development of anorexia nervosa, or identified as risk factors. [2]

And as with other eating disorders, treatment for the condition is typically multifaceted, to address these various underlying issues. But with AN in particular, weight restoration is typically among the first priorities of treatment, with related mental health issues generally addressed only once weight gain is considered sufficient to make someone medically stable.


8 Anorexia Nervosa Medical Complications

Anorexia nervosa can impact an individual’s physical health in numerous ways. And severe anorexia nervosa can have an even more devastating effect.

Still, there are some conditions that more frequently occur with or are caused by this condition.

Endocrine Changes

The endocrine system carries out some of the most important functions in the body. As a whole, it works to oversee the production and management of hormones and plays a role in maintaining metabolism, which, in turn, dictates how energy is used in the body.

Since these functions are so central to how the rest of the body operates, issues with the endocrine system can be far-reaching and particularly dangerous. And AN is tied to multiple endocrine abnormalities.

Metabolic Issues

The severe limitation of food intake can lead the body to switch into so-called “starvation mode.” This represents an entirely new set of internal priorities, as the body strives to find sources of energy wherever it can, and direct those nutrients to the functions needed for survival.

These changes are in part dictated and in part supported by the endocrine system. And once they take place, they can be difficult to reverse. In fact, those with severe anorexia nervosa often require medically-assisted nutritional rehabilitation at first, as overwhelming the body with too much sustenance after a period of starvation can lead to serious complications.

Menstrual Issues

A common symptom in female patients with AN is hypothalamic amenorrhea, or the loss or disturbance of the menstrual period. The condition is caused by changes in hormone production brought on by limited food intake, and it impacts a large number of biological women and girls who struggle with AN.

Although hypothalamic amenorrhea is not typically life-threatening, the loss of the menstrual cycle is linked to a number of other health risks, including a higher risk of bone fractures around the hip and waist area. And, if left untreated, prolonged amenorrhea can have long-term consequences on reproductive health. [3]


Osteoporosis is a medical condition characterized by weak and brittle bones or decreased bone formation. It can be detected by changes in someone’s areal bone mineral density.

There are several factors linking anorexia nervosa and osteoporosis. [4]

Eating disorder patients with AN often have low body weight. This can lead to low bone mineral density due to a lack of nutrients which are needed for healthy bone development.

In states of starvation, the body may also mine its own bones and bone marrow for essential nutrients, such as calcium and vitamin D, which are needed for survival.

And endocrine changes in biological female patients can lead to low estrogen levels, which may also cause osteoporosis. Estrogen is vital for maintaining bone density in women, and low estrogen levels can increase the risk of osteoporosis. [5]

Gastrointestinal Complications

Individuals with AN often experience gastrointestinal complications throughout their entire digestive tract. [6] These varied conditions can have a number of causes, but many of them are tied to the limited and/or irregular use of the digestive system during anorexia nervosa.

Gastroparesis is one of the most common gastrointestinal complications in anorexia patients. This condition affects the normal movement of food through the stomach, leading to nausea, vomiting, and abdominal pain. The disrupted food movement through the digestive system due to gastroparesis can also contribute to constipation.

Gastroparesis is thought to be caused by the effects of chronic malnutrition on the nerves and muscles of the digestive system. Fortunately, individuals with this medical complication can resolve it through refeeding.

Cardiovascular Complications

Perhaps the most notorious—and dangerous—of the medical consequences tied to AN are the cardiovascular complications commonly brought on by the condition.

Anorexia nervosa can affect the cardiovascular system in a number of ways, due to chronic malnutrition, low body weight, electrolyte imbalances, and other factors connected to the illness. In the most extreme cases, these issues can lead to sudden cardiac death, or sudden death related to the stopping of the heart.

Another common cardiovascular complication in individuals with anorexia nervosa is bradycardia, or a slower-than-normal heart rate. [7] This condition is thought to develop from a combination of factors, including low levels of electrolytes and decreased cardiac output.

In addition, individuals with anorexia nervosa may have decreased heart muscle mass, which can also lead to heart failure.

Kidney Damage

AN has been linked to long-term dysfunction of the renal system, which operates primarily out of the kidneys and works to filter blood, creating urine as a waste byproduct.

The limited or disrupted food intake associated with anorexia nervosa commonly causes electrolyte imbalances, or imbalanced levels of vital minerals and nutrients that help power a number of essential movements in the body and its cells.

Abnormal levels of sodium, potassium, and other minerals can wreak havoc across the body, including by forcing the kidneys to work harder to maintain the body’s fluid and electrolyte balance. This can lead to increased rates of acute kidney injury, chronic kidney disease, and nephrolithiasis, or kidney stones. [8]

And once the kidneys are no longer functioning properly, it opens the door to a host of other physical health issues, including high blood pressure, anemia, and bone disease.

Immune System Dysfunction

Besides impacting the way the body functions, anorexia nervosa can also impact the way it protects itself, as the malnutrition connected to the condition can lead to widespread immune system dysfunction.

In general, the lack of vitamins and minerals within the body works to weaken the immune system, making someone more susceptible to infections and illnesses. As such, individuals with AN may experience more frequent infections, slow wound healing, and other immune-related health problems.

Specifically, anemia, or the lack of iron in the blood, can cause a number of immune-related concerns. Low levels of this mineral can lead to fatigue and other complications that may impede the immune system’s response. [9]

Immune System

Mental Health Complications

As with other mental health disorders, anorexia nervosa is often accompanied by a number of comorbid, or co-occurring, mental health conditions.

Anxiety disorders of all kinds, depression, and chronic low self-esteem are particularly common in patients with AN. [10] And those with anorexia nervosa also face a higher risk of developing other mental health issues, including substance use disorders and suicidal ideation.

In fact, the increased rate of suicide attempts among those with anorexia nervosa (as well as those with bulimia nervosa) are often thought to have more to do with the condition’s high mortality rate than any of the other physical symptoms it causes. [13]

Even in less extreme cases, the mental health complications tied to anorexia nervosa can have a significantly negative impact on someone’s health and well-being. And depression, anxiety, and substance use can worsen the physical symptoms of anorexia nervosa, as well as complicate recovery efforts.

Hematologic Complications

Hematological abnormalities and complications are conditions that impact the quality of the blood. One such condition is anemia, in which the red blood cells cannot carry oxygen to the body’s tissues. This can lead to fatigue, weakness, shortness of breath, or heart complications.

Anemia is a common malady afflicting patients with AN, but there are many hematologic complications of anorexia nervosa, including:

  • Leukopenia: A condition characterized by a low white blood cell count. It leads to an increase in the risk of infections. [11]
  • Thrombocytopenia: A condition in which the body has too few platelets, leading to excessive bleeding and bruising. [12]

Finding Help for Anorexia Nervosa

Anorexia nervosa is a severe psychiatric disorder, which can manifest as myriad physical and mental complications. If left untreated, this can lead to long-term consequences, or even death, in the worst case scenarios.

Fortunately, many effective treatments can help individuals with AN recover and improve their quality of life. Care for AN typically involves a multidisciplinary approach, including:

  • Psychotherapy
  • Medical monitoring
  • Nutritional counseling.

Depending on the illness’s severity, treatment may occur in a hospital, outpatient program, or residential treatment center. Still, there can be no help at all without action.

The first step in finding help for anorexia nervosa is often talking to a healthcare professional. These experts can provide an accurate diagnosis and refer you to appropriate treatment options.

A number of eating disorder hotlines can also help people access information and resources. These services are often free, and allow people to discuss these issues in an anonymous format.

Regardless of where it’s done, seeking help for anorexia nervosa is a courageous step toward recovery. With the proper treatment and support, it is possible to overcome this illness and lead a happy and healthy life.


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  7. Cotter R, Lyden J, Mehler PS, Miceli J, Schuller J, & Krantz MJ. (2019). A case series of profound bradycardia in patients with severe anorexia nervosa: Thou shall not pace? HeartRhythm Case Reports; 5(10):511–515.
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  11. Polli N, Scacchi M, Pecori Giraldi F, Sormani M, Zappulli D, & Cavagnini F. (2008). Low insulin-like growth factor I and leukopenia in anorexia nervosaThe International Journal of Eating Disorders; 41(4):355–359.
  12. Yoshiuchi K, Takimoto Y, Moriya J, Inada S, & Akabayashi A. (2010). Thrombopoietin and thrombocytopenia in anorexia nervosa with severe liver dysfunctionThe International Journal of Eating Disorders; 43(7):675–677.
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Published November 30, 2023 on EatingDisorderHope.com