Critically elucidating the role of selenium.

PURPOSE OF REVIEW: To assess the current role of selenium supplementation in critically ill patients. RECENT
FINDINGS: Studies consistently demonstrate decreased selenium concentration in plasma and whole blood in some critically ill patients, especially those with septic shock, and have suggested that persistent low concentrations may be associated with worse outcomes. However, clinical trials of selenium administration have not consistently or convincingly demonstrated improved outcomes.
SUMMARY: Despite the low selenium content in the body (20-40 mg), selenoenzymes play an important role in antioxidant defense in humans. Selenium administration may be associated with improved outcomes, but further studies are needed to determine the precise mechanism of action. Studies are also needed to determine optimal dosing regimens, and to identify those patients in whom this approach is likely to be most effective. Currently, doses below the tolerable upper intake level (400 microg) may be used in supplementation. Higher doses (up to the level of no adverse effect, 800 microg) may be of interest and need to be studied further. The pro-oxidant effects of selenocompounds, especially sodium selenite, which vary depending on the compound, dose, and concentration, also need to be assessed further for their toxicity and potential therapeutic use in patients with septic shock.