In a KiSel-10 trial sub-study, Prof. Urban Alehagen and a team of researchers have observed a positive association between the levels of serum selenoprotein P (SELENOP) and the serum levels of both total selenium and the seleno-enzyme glutathione peroxidase GPx3. Accordingly, the researchers noted that the serum SELENOP concentration level can serve as a useful biomarker for the selenium status of individual study participants and of individual patients [Alehagen 2024].
Important to note here is that daily supplementation with 200 mcg of selenium from a selenium-enriched yeast preparation induced significantly higher serum concentrations of SELENOP in elderly community dwelling Swedish citizens, average age: 77 years. In the active treatment group, the selenium supplementation resulted in the saturation of SELENOP in the blood at a serum selenium level of 146 mcg/L. The selenium supplementation also resulted in a saturation of GPx3 at a serum selenium level of 99 mcg/L. This positive association between the level of SELENOP, on the one hand, and serum selenium and GPx3, on the other hand, is in agreement with the existing research literature [Alehagen 2024].
The dietary intake of selenium varies considerably around the world. Many people live in regions with selenium-poor soil and, consequently, selenium-poor crops and fruits. These people are at risk of inadequate selenium supply and poor health because of selenium deficiency.
What is SELENOP?
SELENOP is a selenium-dependent protein that is synthesized in the liver using the amino acid selenocysteine. SELENOP then serves as the primary transporter of selenium to the organs and tissues. Efficient transport mechanisms in the body ensure that organs that are important for reproduction and survival have high priority for supply with selenium. SELENOP preferentially transports selenium to essential tissues like the brain and the endocrine glands [Schomburg 2022].
Augmented SELENOP Levels and Health Benefits
Supplementation with a selenium-enriched yeast preparation that comprises approximately 20 different species of selenium has augmented significantly the serum level of SELENOP [Alehagen 2024].
In the present KiSel-10 trial sub-study, the following significant associations of serum SELENOP level and health-related outcomes are specifically of interest [Alehagen 2024]:
Effect on inflammation
An inverse association between serum SELENOP levels at the study start and biomarkers for inflammation; the lower the SELENOP level, the higher the level of inflammation.
Effect on longevity
A direct association between lower levels of SELENOP at the study start and shorter telomere lengths seen in a follow-up study; the selenium
supplementation that caused an increase in SELENOP apparently eliminated the differences in telomere length in the low vs. high SELENOP
groups at the study start. Thus, higher SELENOP levels are associated with the prospect of a longer life.
Effect on quality of life
A direct association between higher levels of SELENOP and better quality of life; there were significant associations between higher SELENOP levels and better performance on three of the eight domains of the SF-36 instrument; both physical and mental domains of the instrument were affected.
Effect on survival
An inverse association between the levels of SELENOP and the risk of cardiovascular mortality; there was significantly higher cardiovascular disease mortality in study participants with the lowest level of SELENOP; even when adjusted for relevant confounders, there was a 79% increased cardiovascular disease mortality risk associated with low SELENOP levels.
An inverse association between the levels of SELENOP and the risk of all-cause mortality; in comparisons of the lowest SELENOP quartile with the highest SELENOP quartile, there was significant lower all-cause mortality in study participants who had a higher concentration of SELENOP.
Effect on prognosis
All three selenium biomarkers identified the same tendency toward an increased mortality risk with lower levels of all three measures; compared to GPx3 and selenium levels, however, serum SELENOP levels showed increased prognostic power.
Conclusion: SELENOP is a Valuable Selenium Biomarker
The KiSel-10 sub-study has shown significant associations between serum SELENOP levels and 1) inflammation, 2) length of telomeres, 3) quality of life, and 4) mortality.
Daily supplementation with selenium from a selenium-enriched yeast preparation for four years has improved SELENOP expression and facilitated systemic tissue selenium bioavailability and resulted in positive health effects.
Saturation of SELENOP in serum most likely results in the delivery of selenium to the peripheral tissues.
With its relatively high saturation point, SELENOP should be considered the most appropriate biomarker for the regulated selenium pool.
Low serum SELENOP values may be the result of either low selenium intake or increased inflammation or both.
Sources
Alehagen U, Aaseth J, Schomburg L, Larsson A, Opstad T, Alexander J. Selenoprotein P increases upon selenium and Coenzyme Q10 supplementation and is associated with telomere length, quality of life and reduced inflammation and mortality. Free Radic Biol Med. 2024 Jul 2;222:403-413.
Schomburg L. Selenoprotein P – Selenium transport protein, enzyme and biomarker of selenium status. Free Radic Biol Med. 2022 Oct;191:150-163.
The information presented in this review article is not intended as medical advice. It should not be used as such.
15 August 2024