Absorption, distribution, metabolism and excretion (ADME) of oral selenium from organic and inorganic sources: A review

Niels Hadrup, Gitte Ravn-Haren*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Background
Selenium is a trace element traditionally ingested either in its organic form via food or in its inorganic form through nutritional supplements, while selenium formulated as nanoparticles is a putative long-acting alternative. To understand the physiology and toxicology of the different selenium formulations, it is important to determine how their selenium content is absorbed, distributed, metabolised and excreted; therefore, we reviewed their biokinetics following oral exposure.

Methods
We retrieved and reviewed the literature on the absorption, distribution, metabolism, and excretion of oral exposure to different forms of selenium.

Results
Selenium in both the organic form (containing carbon to selenium chemical bonds) and the inorganic form is absorbed into the blood in humans. The mean normal blood level of many studies was 139 μg/L. There are indications that selenium from organic sources is more bioavailable than selenium from inorganic sources. Selenium is distributed throughout the body, including in breast milk. The elimination of selenium mainly involves the faecal and urinary pathways, whereas breath, saliva and hair are minor contributors. Urinary metabolites include trimethylselenium ions, selenosugars and Se-methylselenoneine.

Conclusion
Selenium is absorbed to a high extent, and selenium from organic sources is more bioavailable than from inorganic sources. Selenium, as expected as an essential trace element, is distributed throughout the body. Selenium is extensively metabolised, and various excretion metabolites have been identified in both urine and breath, while some selenium is also excreted via faeces.
Original languageEnglish
Article number126801
JournalJournal of Trace Elements in Medicine and Biology
Volume67
Number of pages12
ISSN0946-672X
DOIs
Publication statusPublished - 2021

Fingerprint Dive into the research topics of 'Absorption, distribution, metabolism and excretion (ADME) of oral selenium from organic and inorganic sources: A review'. Together they form a unique fingerprint.

Cite this