How Eating Disorders Like Anorexia and Bulimia Cause Kidney Damage

Eating disorders such as anorexia nervosa and bulimia nervosa can place significant strain on the kidneys. Eating disorder behaviors like restricting food and purging disrupt fluid balance and electrolytes, impacting the kidneys over time. Signs to watch for include dehydration, changes in urination, swelling, high blood pressure, nausea and vomiting. Seek medical attention if these signs are observed in individuals with eating disorders.

Can anorexia and bulimia cause kidney failure?

Kidney complications are a common and often underrecognized consequence of eating disorders such as anorexia nervosa and bulimia nervosa.

• Nearly 70% of patients with anorexia nervosa are affected by kidney complications.
• Up to 37% have impaired kidney function, ranging from electrolyte disturbances and dehydration to acute kidney injury (kidney failure) and chronic kidney disease.^1,2

How do eating disorders impact the kidneys?

Eating disorder behaviors like restrictive eating, vomiting, laxative misuse and diuretic abuse place repeated stress on the kidneys by disrupting fluid balance and electrolyte regulation. Over time, these behaviors can impair the kidneys’ ability to filter waste and function, leading to potentially serious and long-term renal complications.

Purging

Patients who purge, such as those with bulimia nervosa or anorexia nervosa binge-eating and purging (AN-BP) subtype, are at risk of fluid loss and hypokalemia (low potassium) from self-induced vomiting or misuse of diuretics and laxatives. Hypokalemia, especially if persistent, can induce a variety of changes in the kidney function.³

Dehydration

Patients with anorexia nervosa restricting (AN-R) subtype are frequently dehydrated due to insufficient liquid intake. Dehydration can impair kidney function.

Food restriction and malnutrition

Prolonged malnutrition from food restriction can cause the body to break down muscle for energy, a condition known as rhabdomyolysis. This releases protein (myoglobin) into the blood, which, when filtered by the kidneys, can clog the tubules and damage kidney cells.

What renal complications are related to eating disorders?

Over time, dehydration and electrolyte imbalances related to eating disorders can cause serious side effects including a loss of kidney function. Understanding these risks can help people recognize complications early and seek appropriate care.

Kidney stones

Kidney stones (nephrolithiasis) are common in dehydration, which is associated with eating disorders. Dehydration concentrates the urine, making it more likely that minerals such as calcium, oxalate and phosphate will clump together and crystallize. Over time, these crystals form kidney stones, which can cause pain as they pass through the urinary tract or block it completely.

Hypokalemic nephropathy

Chronic hypokalemia can lead to tubular vacuolization, lymphocytic infiltration and tubulointerstitial fibrosis in the kidney — collectively known as hypokalemic nephropathy.¹ This progressive renal disease is common among patients with eating disorders, affecting¹:

• Up to 14.2% of patients with AN-R
• 42.4% of patients with AN-BP
• 26.2% of patients with bulimia nervosa

If left untreated, it can lead to end-stage renal disease.

Acute kidney injury

Acute kidney injury (AKI) is a group of conditions characterized by a sudden decrease in glomerular filtration rate (GFR), an increase in creatinine and/or low urine output, leading to excess fluid, sodium buildup and electrolyte disturbances due to impaired kidney function.² AKI can progress to chronic kidney disease (CKD).²

Chronic kidney disease

Chronic hypokalemia and hypovolemia can result in irreversible kidney damage and the development of chronic kidney disease.⁴ CKD consists of five stages⁵:

• Stage 1: GFR 90+ and kidney damage (uACR 30+) for at least three months
• Stage 2: GFR 60-89 and kidney damage (uACR 30+) for at least three months
• Stage 3a: Mild to moderate loss of kidney function (GFR 45-59) for at least three months
• Stage 3b: Moderate to severe loss of kidney function (GFR 30-44) for at least three months
• Stage 4: Severe loss of kidney function (GFR 15-29) for at least three months
• Stage 5: End-stage renal disease (GFR < 15) for at least three months or requiring dialysis

A study of patients with AN-R found that 72% of patients had an estimated GFR less than 90, with 59% of these patients having stage 2 CKD and 13% having stage 3 CKD.¹

End-stage renal disease

End-stage renal disease (ESRD), also known as kidney failure or end-stage renal failure, is a lesser-known complication of eating disorders, despite up to 5% of those with anorexia nervosa developing kidney failure.¹

During kidney failure, the kidneys are no longer able to function and cannot balance electrolytes or fluid levels or remove waste (uremia). Without interventions such as renal replacement therapy (RRT) or kidney transplant, patients are at risk of death within days.

A study¹ identified risk factors for kidney failure in those with eating disorders, such as:

• Low body mass index (BMI)
• Prolonged disease duration
• Bradycardia

What are the signs of kidney damage?

Kidney problems can develop quietly but there are some early warning signs. Watch for changes in urination, swelling, fatigue, electrolyte imbalances, nausea/vomiting and high blood pressure.

Changes in urination

A change in urination is the most common sign of kidney dysfunction. Watch for changes in frequency, changes in color and the presence of blood in urine. All can indicate kidney problems.

Edema (swelling)

Edema is another common sign of kidney problems. As the kidneys struggle to remove excess fluid and sodium, edema can form in the:

• Legs
• Ankles
• Feet
• Hands

Fatigue and weakness

As the kidneys fail to efficiently remove toxins from the blood, patients may experience tiredness, fatigue, weakness, difficulty concentrating or brain fog.

Electrolyte imbalances

Abnormal levels of potassium, sodium and phosphorus are also common in patients with kidney dysfunction.

Nausea or vomiting

As waste products accumulate in the bloodstream, they can trigger gastrointestinal symptoms like nausea and vomiting.

High blood pressure

The kidneys play a key role in blood pressure regulation, and kidney dysfunction can cause or worsen hypertension.

How do you treat kidney complications related to eating disorders?

Depending on the severity of kidney damage, treatment for kidney complications primarily focuses on medical stabilization and restoring nutritional balance. At times, more advanced interventions, such as dialysis and kidney transplant, may be necessary.

Medical stabilization

While kidney-related complications can escalate quickly, many can be brought under control with timely medical stabilization. This process focuses on correcting fluid and electrolyte imbalances, managing acute kidney injury and monitoring vital organ function to prevent further damage.

Nutritional rehabilitation

Although the medical complications of kidney dysfunction can be serious and frightening, many improve significantly with consistent nutrition therapy. Nutritional rehabilitation supports adequate blood volume, stabilizes electrolytes and reduces ongoing stress on the kidneys, allowing renal function to stabilize when possible.

Without adequate nutrition, dehydration, electrolyte abnormalities and kidney strain may persist or worsen, making nutrition therapy a critical foundation for both medical recovery and long-term health.

Dialysis

For those with end-stage renal disease, dialysis is the only treatment option until a patient receives a kidney transplant. Two of the most common forms of dialysis are:

• Hemodialysis: Filtering blood externally using a machine three to five times a week
• Peritoneal dialysis: Filtering blood using the abdominal lining (peritoneum) as a filter daily

Kidney transplant

Kidney transplant replaces kidney function rather than simply supporting it, as dialysis does. During a transplant, a healthy kidney from a donor is surgically placed in the recipient’s body.

Find help for a severe eating disorder

If you are dealing with kidney problems related to an eating disorder, getting specialized care early is important. Medical stabilization and targeted nutrition support provide a foundation for both physical recovery and emotional healing. With the right guidance and support, symptoms can improve and you can take meaningful steps toward recovery.

Start here with a free assessment.

References

1. Puckett, L., Mehler, S., & Mehler, P. (2022). Kidney disease as a medical complication of eating disorders. Nature Reviews Nephrology, 18(11), 677-678. https://www.acute.org/kidney-disease-medical-complication-eating-disorders
2. Puckett, L. (2023). Renal and electrolyte complications in eating disorders: A comprehensive review. Journal of Eating Disorders, 11, Article 26. https://www.acute.org/publications/renal-and-electrolyte-complications-eating-disorders-comprehensive-review
3. Hoorn, E.J. (2025, October). Hypokalemia-induced kidney dysfunction (M. Emmett & J. P. Forman, Eds.). UpToDate. https://www.uptodate.com/contents/hypokalemia-induced-kidney-dysfunction
4. Bouquegneau, A., Dubois, B.E., Krzesinski, J., & Delanaye, P. (2012). Anorexia nervosa and the kidney. American Journal of Kidney Diseases, 60(2), 299-307. https://doi.org/10.1053/j.ajkd.2012.03.019
5. National Kidney Foundation. (n.d.). Stages of chronic kidney disease (CKD). https://www.kidney.org/kidney-topics/stages-chronic-kidney-disease-ckd