People who suffer from the eating disorder bulimia nervosa go through bouts of binge eating that are often followed by purging to avoid weight-gain and relieve the feeling of being uncomfortably full. The purge can involve misuse of laxatives or diuretics and self-induced vomiting. These measures upset the body’s natural balance of fluids and ions and over time can lead to medically significant imbalances in electrolytes such as calcium, magnesium, potassium and phosphate.
People with bulimia nervosa often appear to be normal weight or slightly overweight, but their abuse of laxatives or diuretics or frequent self-induced vomiting can seriously perturb their body’s levels of electrolytes. A doctor who suspects bulimia based on tell-tale signs such as enlarged salivary glands, tooth problems, or calluses on the hands from self-induced vomiting can quantify the level of various electrolytes in the body using a standard blood test called the chem-20, says MedlinePlus, a website of the National Institutes of Health. However, in her article in the April 2010 volume of “Nutrition in Clinical Practice”, Dr. Jessica Setnick cautions that laboratory results within normal limits do not always accurately reflect the bulimic patient’s true health status.
Low potassium levels, called hypokalemia, can result when bulimics purge using laxatives or vomiting. Hypokalemia is a serious medical condition, potentially causing extreme muscle weakness that borders on paralysis and fatal disruption of the normal heartbeat rhythm. According to Dr. Catherine Miller and Dr. Neville Golden in their April 2010 article in “Nutrition in Clinical Practice,” laboratory tests often reveal hypokalemia in bulimics. Even bulimics who are otherwise healthy are about 7 times more likely than non-bulimics to have hypokalemia, according to Dr. B.E. Wolfe’s work published in the March 2001 volume of “International Journal of Eating Disorders.”
Low blood levels of calcium, called hypocalcemia, can occur when bulimics purge using diuretics. Although severe hypocalcemia can cause fatal disruption of the normal heart rhythm, in the short term, mild to moderate hypocalcemia usually does not cause symptoms. Over the long term, even mild hypocalcemia leaches calcium from bones that can ultimately lead to osteoporosis. Even though purging can cause a net loss of circulating calcium ions from the body, blood levels can fall within the normal range as the body robs calcium stores from the bones to compensate.
Bulimics frequently suffer from low blood levels of chloride ions, called hypochloremia. Frequent vomiting depletes chloride levels. Dr. B.E. Wolfe’s work demonstrated that 8.1 percent of otherwise-healthy bulimics have hypochloremia, compared to less than 1 percent of non-bulimics.
Other Types of Electrolyte Imbalances
Chronic abuse of laxatives depletes blood levels of magnesium and phosphates, causing hypomagnesemia and hypophosphatemia. All types of purging behaviors can cause dehydration, and with the reduced blood volume, blood levels of ions might appear to lie within the normal range. However Dr. Setnick cautions that with rehydration and a return to normal blood volume, electrolyte levels can fall to dangerous levels.
- MedLine Plus: Bulimia
- University of Maryland Medical Center: Complications of Bulimia
- “Nutrition in Clinical Practice”; Jessica Setnick; Micronutrient deficiencies and supplementation in anorexia and bulimia nervosa: a review of literature; April, 2010.
- “Nutrition in Clinical Practice”; Catherine Miller and Neville Golden; An introduction to eating disorders: clinical presentation, epidemiology, and prognosis; April, 2010.
- "International Journal of Eating Disorders"; B.E. Wolfe et al.; Laboratory screening for electrolyte abnormalities and anemia in bulimia nervosa: a controlled study; March 2001.