Macrocytic anemia induced by selenium deficiency in the course of anorexia nervosa: A case report

Anorexia nervosa is characterized by an extreme fear of weight gain. Clinicians often prescribe meal replacement shakes if patients are unable or unwilling to consume typical foods. However, these shakes sometimes lack essential micronutrients, such as selenium, which may lead to health risks. Moreover, selenium deficiency induces macrocytic anemia. Herein, we present a case of a patient with anorexia nervosa with macrocytic anemia due to selenium deficiency, which was alleviated by selenium supplementation.

An 18-year-old female was admitted to our hospital. The patient was diagnosed with anorexia nervosa. Ultimately, she was unable to walk independently because of fatigue and electrolyte disturbances.

On admission, the height, weight, and body mass index of the patient were 158.5 cm, 27.1 kg, and 10.8, respectively. Our treatment for anorexia nervosa showed relative effectiveness, and the patient's body weight recovered to 29.2 kg by day 60. However, the mean corpuscular volume increased from day 20, suggesting macrocytic anemia.

Despite our vitamin B12 and folic acid supplementation interventions, the mean corpuscular volume continued to rise. On day 60, the patient was diagnosed with selenium deficiency, and selenium administration of 100 μg/day was initiated.

The macrocytic anemia in the patient was alleviated, and treatment for anorexia nervosa was continued in our hospital.

To the best of our knowledge, this is the first case of macrocytic anemia induced by selenium deficiency with anorexia nervosa comorbidity, underscoring the importance of selenium supplementation in patients with anorexia nervosa, especially in those with macrocytic anemia.