Selenium and male infertility

The selenium containing selenoprotein glutathione peroxidase 4 (GPx4) is present in sperm cells at surprisingly high levels. Biochemists say that GPx4 carries out two functions in sperm cells. It protects the developing sperm calls against oxidative damage caused by toxic peroxides, and it contributes later to the structural integrity of the mature sperm cells [Strauss].
Here is a little-known fact.  Human testicles contain high concentrations of one of the important selenium containing antioxidant enzymes, the selenoprotein glutathione peroxidase number 4 (GPx4).  Furthermore, the testicles have special receptors for another of the important selenoproteins, the selenoprotein P [Rayman 2012].

Adequate intakes of selenium for the synthesis of the selenoproteins are necessary to produce mature and viable sperm.  The selenoprotein GPX4 seems to be indispensable:

  • to the development and maturation of the sperm cells
  • to the antioxidant protection of the sperm cells
  • to the structural cohesiveness of the sperm cells
  • to the motility and viability of the sperm cells [Foresta]

Selenium and semen quality
What are we talking about here?  Let’s define some terms that are relevant to male fertility.

Our bodies produce semen by combining sperm cells from the testicles with various fluids from the seminal vesicles, the prostate, and the two small glands called Cowper’s glands.  The semen needs to contain high counts of sperm cells – perhaps 200 million plus – and needs to contain sperm cells capable of good motility if one of the sperm cells is to succeed in reaching and fertilizing the mature female egg.

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Selenium and thyroid disorders

The thyroid is the little endocrine gland at the base of our necks.  It produces hormones that affect nearly every organ in our bodies.  Specifically, the thyroid hormones regulate our cells’ metabolism. Both iodine and selenium are needed in adequate amounts for optimal thyroid functioning.

Iodine is an essential component of the thyroid hormones.  After iodine, selenium is arguably the micronutrient most important to the thyroid gland. Proportionally, there is more selenium in the thyroid gland than there is selenium in any other organ in the body. There are good reasons for the presence of selenium in the thyroid gland.  Iodine and selenium are both required for thyroid hormone synthesis and function.

Our bodies do not make selenium. We must get the selenium that we need from our food and from supplements. The selenium that we absorb is incorporated into the amino acid selenocysteine. Selenocysteine, then, is a necessary component of some 25 selenoproteins that are needed for various biological functions.

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How much selenium every day?

Yes, good health depends on good genes. But it also depends on good diet, good exercise, good sleep, and adequate intakes of essential bio-nutrients such as selenium and Coenzyme Q10.

The proper daily dosage of selenium for normal people?   Normal people?  How many of us are approximately normal?  68 percent of us, perhaps?  Yes, we humans are more the same in many ways than we are different.  However, there is considerable biochemical variation amongst us humans.  So, it is difficult to say who is average and normal and then suggest an ideal daily dosage of selenium.

What do the numbers from selenium studies say?
Let’s look at the numbers from published research and see what sense we can make of them.  Remember: we humans need adequate plasma selenium concentrations for optimal antioxidant and anti-viral and anti-carcinogenic protection [Schrauzer 2009].

Putative beneficial range for plasma selenium status
Hurst and Fairweather-Tait et al, researchers based at Norwich Medical School, University of East Anglia, in the United Kingdom have suggested that the “putative beneficial range” lies between 120 and 150 nanograms of selenium per milliliter of plasma [Hurst 2010].

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