Selenium Intakes and Health Outcomes

Selenium and good health. How much do we need? How do we get it? Generally speaking, our family and friends do not know just how important selenium is to good health. Our bodies cannot synthesize selenium. We are dependent upon food for an adequate daily intake of this essential trace element.

Salmon rich in selenium
Depending upon where we live, the selenium content of our food may be too low. Wang et al [2023] estimate that approximately one billion people worldwide lack sufficient selenium in their diet.
In many regions of the world, the soil and the foodstuffs have a poor selenium content. Accordingly, the daily intake of selenium varies considerably. Many people have an inadequate supply and thus risk poor health outcomes as a result. For example, in much of Europe, the UK, and the Middle East, there are widespread reports of suboptimal selenium status. Supplementation is necessary in selenium-poor regions [Stoffaneller & Morse 2015].

Selenium Intake and Selenoprotein Synthesis

We need an adequate intake of selenium in order to synthesize the 25 known selenoproteins that have diverse tissue distributions and biological functions in humans. The selenoproteins incorporate the selenium as a component of the 21st amino acid, selenocysteine [Schomburg & Schweizer 2009].

Many selenoproteins function as enzymes and factors that regulate redox reactions and immune responses. The glutathione peroxidases, thioredoxin reductases, iodothyronine deiodinases, and the primary selenium transporter in the blood circulation, Selenoprotein P, are representative selenoproteins [Wang 2023].

Selenium Intake and Selenium Supplementation

Adequate selenium intake, as compared with sub-optimal selenium intake, has been associated with a reduced risk of the following conditions [Wang 2023]:

  • all-cause mortality
  • depression
  • digestive system cancers
  • Keshan disease
  • Kashin-Beck disease in children

Selenium supplementation has been associated with improvements in the following conditions [Wang 2023]:

  • autoimmune thyroid disease
  • cardiovascular disease
  • polycystic ovary syndrome
  • preeclampsia in pregnancy
  • sperm quality
  • susceptibility to infections
Adequate Selenium Intakes for Good Health

Researchers have developed the concept of a U-shaped relationship between selenium intake/status and selenium’s health effects. The concept is somewhat simplistic but useful nevertheless [Rayman 2020, figure 2].

The U-shaped graph between selenium status (the x-variable) and the probability of various health outcomes (the y-variable) shows that the best health outcomes are associated with a serum selenium status of approximately 125 micrograms per liter. The risk of poor health outcomes appears and increases when the serum selenium concentration drops below 100 micrograms per liter [Rayman 2012, figure 3].

The serum selenium concentration associated with minimal mortality risk seems to lie between 125 and 145 micrograms per liter [Rayman 2012, figure 4].

Conclusion: Selenium Necessary for Good Health
  • Many of us, especially if we live in Europe or the Middle East, live in regions that have poor selenium content in the soil and in the food.
  • Depending on where we live, selenium supplementation may be necessary.
  • The selenium intake that is desirable is an intake that maintains serum selenium status at approximately 125 mcg/L.

Rayman MP. Selenium and human health. Lancet. 2012 Mar 31;379(9822):1256-68.

Rayman MP. Selenium intake, status, and health: a complex relationship. Hormones (Athens). 2020 Mar;19(1):9-14.

Schomburg L, Schweizer U. Hierarchical regulation of selenoprotein expression and sex-specific effects of selenium. Biochim Biophys Acta. 2009 Nov;1790(11):1453-62.

Stoffaneller R, Morse NL. A review of dietary selenium intake and selenium status in Europe and the Middle East. Nutrients. 2015 Feb 27;7(3):1494-537.

Wang P, Chen B, Huang Y, Li J, Cao D, Chen Z, Li J, Ran B, Yang J, Wang R, Wei Q, Dong Q, Liu L. Selenium intake and multiple health-related outcomes: an umbrella review of meta-analyses. Front Nutr. 2023 Sep 13;10:1263853.

The information presented in this review article is not intended as medical advice and should not be used as such.

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