Selenium renal homeostasis is impaired in patients receiving long-term total parenteral nutrition

Selenium deficiency has been reported previously in patients receiving long-term total parenteral nutrition (TPN) without selenium supplementation in their solutions. The recommended dietary allowance for selenium is 0.87 microgram/kg, of which 80% is absorbed. We studied 28 adult long-term TPN patients aged 21 to 79 years (mean, 51.2 +/- 3.0 years) who have received TPN for 8.3 +/- 4.4 years. They receive 40 to 60 micrograms of selenium daily in their TPN solution. Twenty-one (75%) of 28 patients had low serum selenium levels. Of the patients with low serum selenium levels, 15 (73%) had elevated urinary selenium losses. However, no significant correlation between serum or urine selenium levels and glomerular filtration rate (measured by indium-111-diethylenetriamine pentaacetic acid clearance) or renal tubular function was observed. We conclude that the previously described renal homeostatic mechanism for selenium conservation may be significantly impaired in patients receiving long-term TPN. Such patients may require much larger doses of selenium than previously recommended. Therefore, patients receiving long-term TPN should have their serum selenium level monitored even though they receive daily selenium supplementation.