{Reference Type}: Journal Article
{Title}: Toxicity of repeated oral intake of organic selenium, inorganic selenium, and selenium nanoparticles: A review.
{Author}: Hadrup N;Ravn-Haren G;
{Journal}: J Trace Elem Med Biol
{Volume}: 79
{Issue}: 0
{Year}: 2023 Sep 2
{Factor}: 3.995
{DOI}: 10.1016/j.jtemb.2023.127235
{Abstract}: <B>BACKGROUND: </B>To protect from toxicity at supra-essential doses of selenium, it is important to determine dose levels at which adverse effects occur.<BR><B>METHODS: </B>We identified relevant literature on the repeated dosage of selenium and extracted dose descriptors on reported endpoints, except on genotoxicity/carcinogenicity.<BR><B>RESULTS: </B>Selenium forms with toxicological data were organic ones: selenomethionine, selenocystine/selenocysteine; and inorganic ones, including selenite (SeO32-), selenate (SeO42-), selenium sulphide (SeS2), selenide (Se2-) and selenium nanoparticles. Clinical signs of selenium toxicity in humans include a garlicky-smelling breath, hair loss, and nail changes. One human study showed increased mortality following daily ingestion of 300 µg Se per day for 5 years, equal to a lowest-observed-adverse-effect level (LOAEL) of ∼4.3 µg/kg bw/days. The corresponding no-observed-adverse-effect level (NOAEL) was ∼2.9 µg Se/kg bw/day. One study reported an increased risk of type 2 diabetes after ∼2.9 µg Se/kg bw/day, but other studies with similar doses found no increases in mortality or incidence of type 2 diabetes. NOAELs on affected body weight in animal studies were 0.24-1.2 mg Se/kg bw/day. Other endpoints of selenium toxicity in animals include hepatotoxicity with a NOAEL as low as 2 µg/kg bw/day in rats, as well as gastrointestinal, cardiovascular, and reproductive toxicities with NOAELs of 0.6 (gastrointestinal), 0.08, and 0.4 (cardiovascular) and ≥ 0.04 mg Se/kg bw/day (reproductive), respectively.<BR><B>CONCLUSIONS: </B>Dose descriptors describing selenium toxicity were as low as 2-3 µg Se/kg bw/day.