Selenium plays an important role in optimal immune and endocrine system function. The role that selenium plays with respect to thyroid function is complex [Chmura 2022]:
The thyroid gland is the organ with the greatest amount of selenium per gram of tissue.
A 2022 review highlights the following relationships between selenium deficiency and thyroid gland dysfunction [Chmura 2022]:
Aging. Getting up in years. Striving to live as long as possible and to be as strong and healthy as possible. At some point, good health becomes a more important concern than wealth. Optimal selenium status is important to good health [Alehagen 2021].
In a review article, Professor Urban Alehagen and Professor Jan Aaseth list the following conditions associated with biological aging [Alehagen 2021]:
Getting old is inevitable. Biological aging necessarily involves a weakening of the immune system and increased susceptibility to diseases and environmental stresses.
Selenium deficiency is associated with mitochondrial dysfunction, oxidative stress, and inflammation [Alehagen 2021].
Mitochondrial injuries are an important factor in the aging of human cells. A by-product of the mitochondrial generation of ATP energy in the cells is the production of reactive oxygen species, some of which are useful and some of which are harmful. The leakage of these harmful free radicals from the mitochondrial respiratory chain increases with age, which results in cellular oxidative damage, whenever there are not enough antioxidants to neutralize the effects of the free radicals.
Heart disease prevention. In the KiSel-10 Study, combined supplementation of community living senior citizens for four years with an organic high selenium yeast (200 mcg selenium/day) and Coenzyme Q10 in the ubiquinone form (2 x 100 mg/day) prevented an increase in fibroblast growth factor 23 and reduced the risk of cardiovascular disease [Alehagen Feb 2022].
Professor Urban Alehagen explains that fibroblast growth factor 23 is a hormone that is secreted primarily from the osteocytes (i.e., mature bone cells) into the blood. From the blood circulation, the hormone acts on fibroblast growth factor receptors in the heart, intestine, kidney, and parathyroid gland [Alehagen Feb 2022].
Fibroblast growth factor 23 is mainly active in the metabolism of vitamin D and phosphorus. However, there have been reports that indicate an association between increased fibroblast growth factor 23 levels and cardiovascular mortality even in the patients with no sign of kidney disease [Alehagen Feb 2022].
Thyroid disease. Hyperthyroidism. Adjuvant treatment of thyroid disease with selenium yeast supplementation. All topics of interest. At this writing (August 2022), we await the publication of the outcomes of the GRASS clinical trial. GRASS is the acronym for the selenium supplementation for patients with Graves’ hyperthyroidism study [study protocol described by Watt 2013].
Hyperthyroidism is caused by a number of conditions, including Graves’ disease, which is a common cause. Graves’ disease is the result of immune system disorder. It can affect anyone, but it is more common in women and in individuals under the age of 40.
Anti-aging effects. Longevity. Telomere length. Daily supplementation of senior citizens with selenium and Coenzyme Q10 for 42 months slowed down telomere shortening and reduced the risk of death from cardiovascular disease [Opstad 2022]. The two substances in combination — selenium and Coenzyme Q10 — may be the key to slowing down biological ageing.
Telomeres are the segments of DNA sequences that protect the ends of chromosomes from becoming frayed or tangled. Every time a cell divides, the telomeres become a little bit shorter. When, with increasing age, the telomeres become too short, the cell cannot divide successfully, and the cell dies [National Human Genome Research Institute 2022].
Breast cancer prognosis is especially poor in patients with low serum selenium and serum selenoprotein P concentrations. Now, researchers have discovered natural autoantibodies with antagonistic properties to selenoprotein P uptake in breast cancer patients and in patients with thyroid disease [Demircan 2022; Sun 2022].
Selenium is an essential trace element that has numerous biological functions in the body, most of which are carried out by selenium-containing selenoproteins. Among the more important selenoproteins are selenoprotein P, the main transporter of selenium in the blood, and glutathione peroxidase 3 (GPX3), an important antioxidant.
The human body does not synthesize selenium. Human cells are dependent upon selenium sources in the diet. Unfortunately, the selenium content in the soil and in food varies considerably from region to region in the world. For example, the plasma selenium concentrations in people living in much of Europe are generally below, often well below, 80–90 mcg/L whereas people living in North America generally have plasma selenium levels above 120 mcg/L [Alehagen 2022].
Selenium exposure in the diet and in supplements: in this review article, we summarize the key outcomes of the best selenium exposure studies.
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].
Hypothyroidism is the medical condition caused by an underactive thyroid gland that is not producing sufficient quantities of thyroid hormones. It is the failure of the thyroid gland to function normally.
The standard treatment for Hashimoto’s disease is twofold:
1) treatment with a synthetic hormone called levothyroxine, which works like the T4 hormone that is naturally produced by the thyroid gland
Research done in southern Sweden shows that three blood biomarkers of selenium availability correlated inversely with mortality from breast cancer. The lower the three selenium biomarker levels, the higher the mortality [Demircan 2021].
The blood biomarkers are:
Breast cancer patients with blood concentrations of these three selenium biomarkers in the highest quintile had significantly better chances of survival compared with patients whose blood levels of these substances were in the lowest quintile [Demircan 2021].
Breast cancer patients with low selenium status according to these three biomarkers had the highest mortality risk with an overall survival probability of approximately 50% after 8 years. The difference in survival between the breast cancer patients in the lowest selenium quintile compared to breast cancer patients with at least one biomarker in the highest quintile was especially notable [Demircan 2021].
Health benefits of daily supplementation of senior citizens with a combination of selenium and Coenzyme Q10:
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:
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].
