Case series of selenium toxicity from a nutritional supplement

Abstract

Introduction: Selenium is an essential trace element, but can be toxic in excess. In May 2008, US FDA reported 201 individuals with adverse reactions to liquid nutritional supplements containing excess selenium and chromium resulting in the largest epidemic of selenosis in the history of the United States.

Objective: To describe the clinical features, biomonitoring data of selenium levels, and the estimated total dose of selenium ingestions of nine patients with selenium toxicity who presented after use of a liquid dietary supplement with a formulation error.

Methods: A retrospective observational case series was performed on nine patients presenting to our medical toxicology clinic between March 2008 and May 2008 with symptoms of selenosis after consuming a nutritional supplement. Institutional IRB approval was obtained for this case series.

Results: Supplement testing revealed almost 200 times the reported amount of selenium. There were 5 males and 4 females and their ages ranged from 15 to 57 years (median 46 years, mean 44.2 years). The mean estimated cumulative dose of selenium ingested in our patients was 1.3 gram over a mean period of 37.5 days (10-60 days). In each case, the symptoms of selenium toxicity manifested within 1 week from the start of ingestion. Initial symptoms included alopecia, dystrophic fingernail changes, GI symptoms, and memory difficulties. The initial whole blood selenium concentrations ranged from 150 to 732 mcg/L (reference mean range 123-193 mcg/L) at an average of 27 days post cessation of the formula. The urinary selenium concentrations ranged from 41 to 220 mcg/g Creat (reference < 25 mcg/g Creatinine). None of the patients required more than supportive care for symptoms and none required hospitalization.

Conclusion: Selenium is an essential element, which can result in significant toxicity if ingested in large amounts.