Influence of selenium speciation on its bioavailability from food and food supplements
(2012)
Files
thèse.pdf
Open Access - Adobe PDF
- 5.48 MB
Details
- Authors
- Supervisors
- Abstract
- (en) Like the moon after which it has been named – Selene in Greek –, selenium is an element that has a brigh and a dark side. This oligo-element is essential at a low to moderate level of intake, but becomes toxic at high doses. In Belgium, the recommended values for Se intake have been estimated to be 60 and 70 µg per day for adult women and men respectively. This level of intake is supposed to ensure the maximal activity of the antioxidant selenoenzymes glutathione peroxidases. The Se status of people differs considerably according to the regions of the world because of the heterogeneous repartition of Se in soils, resulting in variable Se contents in food. In Europe, Se content of soils is naturally low and Belgian people could therefore be at risk of Se deficiency. In addition to the dose, another important determinant of the Se impact on the organism is its speciation, i.e. the chemical form of Se. Different species have been shown to have distinct degrees of bioaccessibility, bioavailability, bioactivity and toxicity. This work aimed to improve the current knowledge about how the nature of Se species influences the degree of Se bioavailability, in the context of the Se status and food habits of the Belgian population. This research required the development of an analytical method of Se speciation analysis. This method consisted in an enzymatic ultrasonic-assisted extraction of Se, followed by a chromatographic separation of Se species by HPLC in an ion-pairing reversed-phase partitioning mode, and the final detection of 78Se by ICP-MS in the presence of H2 as a reaction gas. This work first permitted us to calculate that the average Se intake by the general adult Belgian population is 60 µg Se day-1, which is at the lower end of the range of recommended intake. Secondly, we measured decreasing degrees of bioavailability for SeMet > MeSeCys > selenate > selenite, and we showed that these degrees of bioavailability were the consequence of distinct modes of intestinal transport among Se species. Finally, we observed that the bioavailability of Se from different Se-enriched food supplements was generally low, especially for selenite-based ones. This work allowed us to formulate an opinion about the suitability of distinct forms of Se in the context of a Se enrichment of the diet, and opened the door to further research in relation to the species-dependence of Se health effects.
- Affiliations
Citations
Thiry, C. (2012). Influence of selenium speciation on its bioavailability from food and food supplements. https://hdl.handle.net/2078.5/163339