Health Consequences of Anorexia Nervosa
Anorexia Nervosa (AN) is an eating disorder in which individuals significantly restrict food intake, resulting in chronic undernutrition. All systems of the body are affected by long term inadequate energy intake, and, thus, cardiovascular, endocrine, skeletal, gastrointestinal, neurological, and metabolic alterations take place in the setting of AN.
By: Sam Wierzbicki
Anorexia Nervosa (AN) is an eating disorder characterized by restriction of food intake, which may lead to significantly low body weight. Food restriction is motivated by intense fear of weight gain and body image disturbance.¹ It is important to note that individuals can suffer from AN without being at a low body weight. Because the Diagnostic and Statistical Manual of Mental Disorders lists significantly low weight as one of the diagnostic criteria of AN, individuals meeting all criteria other than low weight would likely be given an Atypical Anorexia Nervosa diagnosis, which falls under the category of Other Specified Eating and Feeding Disorders.² The term “atypical” is misleading and rooted in weight stigma. The same health consequences resulting from full-threshold AN occur in Atypical AN. Severe, chronic undernutrition, which is the primary cause of AN-related health complications, can be present at any body weight.³
People suffering from AN are at risk for cardiovascular complications. When the body is significantly undernourished, muscle is broken down to help meet energy needs. Both skeletal muscle and cardiac muscle are lost in this process.⁴ Less cardiac muscle to pump blood throughout the body results in lowered blood pressure.⁴ This loss of muscle also puts AN patients at higher risk for cardiac failure.⁴ Malnourishment may also alter the electrical activity of the heart, increasing the likelihood of sudden death.⁴ Individuals suffering from AN may experience weakness, dizziness, cognitive impairment, fatigue and light-headedness: all of these symptoms may signal cardiac issues resulting from the eating disorder.⁴ With adequate nourishment and restoration to biologically appropriate weight, cardiac impairments can be fully reversed.⁴
In addition to cardiovascular issues, there are a wide range of hormonal abnormalities that may result from AN. For example, thyroid dysfunction is a common consequence of undernourishment.⁴ Hypothyroidism, or underactive thyroid gland, can show up as cold sensitivity, low blood pressure, and low heart rate.⁴ Sex hormones are affected in AN, resulting in decreased libido and, for individuals who menstruate, loss of menstrual cycle.⁴ This change in reproductive system function can be thought of as the body recognizing that there is not enough energy coming in via the diet to support a potential pregnancy. With appropriate weight restoration and sufficient energy intake, these endocrine alterations will normalize.⁴
Hormonal alterations are responsible for bone density loss seen in AN.⁴ Decreased levels of estrogen, progesterone, testosterone, insulin like growth factor-1 and increased cortisol levels all contribute to bone mass depletion.⁴ Decreased body weight and fat cell mass also contribute to greater bone loss and lesser bone formation.⁴ Due to these changes, osteoporosis, where the bones become brittle and weak due to loss of density, is common. In fact, osteoporosis occurs in 40% of women with AN.⁴,⁵ Osteoporosis puts individuals at increased bone fracture risk and at advanced stages can result in height loss, spine curvature, posture alterations, and chronic back pain.⁴,⁶ With normalization of endocrine abnormalities and weight restoration, osteoporosis has the potential to be partially or fully reversed, dependent on individual response.⁴,⁷
Many individuals suffering from AN will experience gastrointestinal complications. These complications, such as gastroparesis or delayed stomach emptying, are a result of chronic undernourishment which slows metabolism.⁴ Inadequate energy intake leads to reduction in size of muscles within the digestive tract, hindering normal functioning.⁴ As a result, individuals with AN may complain of early satiety or feeling full after eating small amounts of food, bloating, and constipation.⁴ Research has shown that gut transit time, the amount of time it takes food to pass through the digestive system, is slowed by 50% in those with AN.4 These complications are treated by gradually increasing caloric intake and restoring weight.⁸
Undernourishment resulting from AN affects the brain’s structure and function. Research has demonstrated an association between AN and brain matter deficits.⁴ These deficits impact cognitive, emotional, and social functioning.⁴ How significantly the anatomy of the brain is altered is theorized to be related to amount of weight lost.⁴ Weight restoration has been shown to increase brain matter volume, though researchers believe the lowest lifetime BMI to be the most significant factor in predicting whether brain structure alterations are reversible.⁴
AN is also associated with a wide range of psychological comorbidities. For example, AN patients may develop obsessive compulsive tendencies in relation to food, weight, or body image.⁴ While these behaviors mimic those of Obsessive Compulsive Disorder (OCD), OCD cannot be diagnosed until weight restoration takes place. This is because the OCD-like behaviors normalize once the brain and body are no longer malnourished.⁴ Additionally, AN patients often suffer from co-occurring psychological disorders, such as depression, anxiety, and personality disorders.⁴ Consequently, suicide is significantly more common among individuals suffering from AN than among the general population.⁴
Long term undernourishment in AN undoubtedly results in lowered metabolic rate.⁴ Depressed metabolism is a consequence of the starving body seeking to conserve as much energy as possible in order to carry out life-sustaining functions. Other physiological changes also contribute to decreased metabolic rate, mainly chronic undernutrition leading to depletion of body protein and lean muscle mass.⁴ Muscle cells are metabolically active; so, the less muscle mass the body carries, the lower metabolic rate will be.⁹ Research has shown that adolescents in a protein depleted state may stunt linear growth.⁴,¹⁰ Signs of depressed metabolism include low heart rate, constipation, fatigue, cold sensitivity, dry skin and brittle hair.⁴ With weight restoration and adequate energy intake, metabolic rate will increase.⁴
If left untreated, health consequences of AN are life-threatening. While these consequences may be alarming to consider, most are fully reversible with appropriate sustained calorie intake and restoration to biologically appropriate weight.
At BALANCE eating disorder treatment center™, our compassionate, highly skilled team of clinicians is trained in diagnosing and treating the spectrum of eating disorders, including anorexia, bulimia, binge eating disorder, compulsive overeating, and other disordered eating behaviors and body image issues. We offer a variety of programs and services targeted at helping clients develop a healthy relationship with food.
Our admissions team would be happy to answer any questions you may have about our programs and services. Book a free consultation call below or read more about our philosophy here.
This post was written by BALANCE Dietetic Intern, Sam Wierzbicki.
Sam is a Dietetic Intern and graduate student at New York University, where she is pursuing her Master’s Degree in Clinical Nutrition. Before beginning her graduate degree in nutrition, Sam worked in the educational field as a private academic tutor to children and adolescents. She completed her undergraduate education at Princeton University, majoring in English literature. After completing her dietetic internship, Sam plans to work in the disordered eating space as a HAES and Intuitive Eating aligned Registered Dietitian.
Resources
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Setnick J. The Eating Disorders Clinical Pocket Guide. Snack Time Press; 2013.
Malnutrition – symptoms. nhs.uk. Published October 23, 2017. https://www.nhs.uk/conditions/malnutrition/symptoms/
Herrin M, Larkin M. Nutrition Counseling in the Treatment of Eating Disorders. Brunner-Routledge; 2013.
Mehler PS, Cleary BS, Gaudiani JL. Osteoporosis in anorexia nervosa. Eating Disorders. 2011;19(2):194-202. doi:10.1080/10640266.2011.551636
Osteoporosis symptoms. Royal Osteoporosis Society. Accessed May 11, 2021. https://theros.org.uk/information-and-support/osteoporosis/symptoms/
Olmos JM, Valero C, del Barrio AG, et al. Time course of bone loss in patients with anorexia nervosa. Int J Eat Disord. 2010;43(6):537-542. doi:10.1002/eat.20731
Gastroparesis. Gaudiani Clinic. Accessed May 11, 2021. https://www.gaudianiclinic.com/gaudiani-clinic-blog/2019/3/18/gastroparesis
Mahan LK, Raymond JL, eds. Krause’s Food & the Nutrition Care Process. Fourteenth edition. Elsevier; 2017.
Haas VK, Kohn MR, Clarke SD, et al. Body composition changes in female adolescents with anorexia nervosa. The American Journal of Clinical Nutrition. 2009;89(4):1005-1010. doi:10.3945/ajcn.2008.26958