Selenium Exposure Studies

Selenium exposure in the diet and in supplements: in this review article, we summarize the key outcomes of the best selenium exposure studies.

Optimal Selenium Intake and Status

In his review of the available research literature, Professor Urban Alehagen, Linköping University, Sweden, concluded that a daily intake of 100–150 mcg of selenium per day is required.

This is the intake level that enables an optimal expression of the important selenoprotein P that transports selenium from the liver to peripheral tissues [Alehagen 2022].  For other selenoproteins to be optimized, i.e., to be fully expressed, Prof. Alehagen argues that selenium status of approximately 120 mcg/L when measured in red blood cells is necessary [Alehagen 2022]. read more

Selenium Supplementation for Senior Citizens

Health benefits of daily supplementation of senior citizens with a combination of selenium and Coenzyme Q10:

  • improved heart function as shown on echocardiograms
  • reduced risk of death from heart disease
  • improved health-related quality of life
Professor Urban Alehagen
In the KiSel-10 Study, Prof. Urban Alehagen and the research team administered 200 mcg/day of selenium and 2 x 100 mg/day of Coenzyme Q10 for 48 months to elderly Swedish citizens whose serum selenium status at baseline was quite low (mean: 67.1 mcg/L). The duration of the study was 48 months. The benefits of the supplementation were improved heart function and reduced risk of death from heart disease.

The combined supplementation seems to work by reducing the extent of oxidative stress, systemic inflammation, and fibrosis in the study participants [Alehagen 2022a].

Now, data from the KiSel-10 Study show the following effects of the combined supplementation with respect to Fibroblast Growth Factor 23 concentrations in blood:

  • Supplementation decreased concentrations of FGF-23 hormones.
  • The study showed a relationship between the circulating level of the FGF-23 and atrial fibrillation.
  • The study showed an association between the concentration of FGF-23 and death from heart disease.
  • The study showed an effect of reduced FGF-23 levels on the risk of death from heart disease that is independent of the level of the cardiac wall tension bio-marker NT-proBNP.
  • There exists a close interrelationship between FGF-23 concentrations and kidney function.
Why are FGF-23 Concentrations Important?

Prof. Alehagen explains that FGF-23 is a hormone that is secreted into the blood circulation. One of its primary functions is the regulation of the vitamin D metabolism and of the phosphorous metabolism in the kidneys.

However, there seems to be an association between FGF-23 activity and cardiovascular mortality even in the absence of kidney disease. Experimental data show that FGF-23 may act as a mediator for cardiac hypertrophy, cardiac fibrosis, and cardiac dysfunction [Alehagen 2022b]. read more

Impact of Selenium Status on Ageing

Selenium is an essential trace element. Essential means that sufficient selenium is necessary for normal cell functioning and that our bodies cannot synthesize selenium for us. We must get it from our diets. Trace element means selenium is a micronutrient that is needed in very small quantities, in microgram quantities. It may be an important element to slow the ageing process.

Elderly couple
Selenium as a component in protective enzymes helps to keep us healthier longer in life. It helps to suppress oxidative stress and to decrease inflammation, to remove misfolded proteins, to decrease DNA damage, and to promote telomere length.

Sufficient selenium status plays an important role in the prevention of cardiovascular diseases, inflammation, and infections. Prof. Margaret P. Rayman, University of Surrey, estimates that serum/plasma selenium status of around 125 mcg/L is optimal for human health [Rayman 2020].

The beneficial work of selenium in the cells and tissues is done by selenoproteins that contain the amino acid selenocysteine in the active center. Among the selenoproteins known to have an antioxidant effect in the body are the glutathione peroxidases (GPX1-4 and GPX6) and the thioredoxin reductases (TXNRD1-3) [Alehagen 2021]. read more

Selenium Status and Inflammation and Heart Disease

Low plasma selenium status is significantly associated with heart disease risk and with elevated blood bio-markers of chronic inflammation.  A 2021 cross-sectional study of elderly individuals in central Italy has revealed that individuals with a plasma selenium status lower than 60 mcg/L are especially at risk of heart disease [Giacconi 2021].

Ancona, Italy
Researchers in Ancona, Italy, have done a cross-sectional study that shows that low plasma selenium status is associated with increased risk of heart disease and with elevated levels of blood bio-markers for chronic inflammation.

Moreover, in the peripheral blood mononuclear cells of elderly individuals diagnosed with heart disease, the researchers found that low plasma selenium status was significantly associated with enhanced gene expression of inflammatory cytokines and chemokines and with a downregulation of sirtuins SIRT-1, SIRT-5, SIRT-6, and SIRT-7 [Giacconi 2021].

Note: The peripheral blood mononuclear cells are lymphocytes (e.g., T cells, B cells, NK cells) and monocytes as distinguished from such blood cells as erythrocytes, granulocytes, and platelets. read more