Selenium Toxicity from a Misformulated Dietary Supplement, Adverse Health Effects, and the Temporal Response in the Nail Biologic Monitor

Abstract

Use of dietary supplements in the U.S. has increased steadily over the last 25 years. While misformulation is uncommon, the consequences can be serious. A March 2008 voluntary market recall removed supplement products responsible for the most serious selenium toxicity outbreak that has occurred in the U.S. We quantified selenium concentrations in the misformulated supplement products, measured the temporal response in the nail biologic monitor, and associated exposure to self-reported selenosis symptoms. Subjects recruited through state health departments and referrals provided samples of the misformulated supplement products, exposure information, monthly toenail and or fingernail clippings or onycholysitic nail fragments, and listed their newly onset adverse health effects attributed to selenium toxicity. Ninety-seven subjects enrolled and submitted at least one test sample. Peak selenium concentrations (up to 18.3 and 44.1 μg/g for toenails and fingernails, respectively) were measured. Multiple samples (52 total) of all six recalled supplement lots were analyzed ranging from 22,300 to 32,200 μg selenium per daily dose. Average consumption was 30.9 ± 13.9 doses; 73 subjects provided follow-up data on selenosis symptoms at 2.50 ± 0.14 years. Nail samples accurately reflect exposure in this selenium toxicity outbreak, which resulted in long-term/permanent adverse health effects.

Selenium speciation in human serum and its implications for epidemiologic research: a cross-sectional study

“…First, its limited statistical power, which was a consequence of the difficulties in finding volunteers available for the study from the general population and of the large amount of resources required for speciation analysis. This reduced the statistical stability of the point estimates, though the coherence across age groups and sexes of some results and the association of serum Se species with dietary supplements and smoking status, as expected [82,83], appear to confirm the reliability of study results [84,85].…”

Selenium behavior in the soil environment and its implication for human health

“…Researches have pointed out that the use of supplements is somewhat uncertain in terms of efficiency due to the Se forms added in commercial supplements, as well as because the supplements are usually unevenly distributed among different population groups (Pietinen et al, 2010). In addition, Aldosary et al (2012) and Morris and Crane (2013) reported several cases of Se intoxication in people due to the intake of these supplements. Industrially fortified foods and supplements mostly contain inorganic Se forms (selenate and/or selenite).…”

Selenium for preventing cancer

“…Furthermore, strong evidence shows different biological activities of the various organic and inorganic forms of selenium (Hazane-Puch 2013; Rayman 2008a; Vinceti 2009; Vinceti 2013c; Weekley 2013), suggesting the opportunity to better char-acterise the specific toxicological and nutritional properties of each selenium species in humans, in animals and in the environment. Recent publications have questioned the adequacy of the current upper ’safe’ limit of intake (Jerome-Morais 2011; Morris 2013; Moyad 2012; Rocourt 2013; Sacco 2013; Vinceti 2009; Vinceti 2013b) and have espoused the need to set different limits for the many different sources of organic and inorganic selenium.…”