Month: May 2026

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Selenium and Male Fertility

Important question: Does selenium play a role in male reproductive health? If so, how?

Man working out with weights
Roughly one in ten men in the USA and in Europe have infertility issues. The extent varies from region to region. Selenium supplementation in selenium-poor regions can improve with sperm morphology and sperm motility.

A 2026 review of the relevant research literature shows the following relationships. A daily intake of selenium at the rate of 100 mcg per day led to significantly improved sperm motility. The same daily 100-mcg intake was associated with an 11 % increase in paternity. Thus, it seems that selenium does play an important role in male fertility. Selenium has dose-dependent antioxidant and endocrine functions [Patel 2026].

How does selenium status improve male fertility?

Sufficient selenium intake and status lead to optimal synthesis of selenoproteins, in particular selenoprotein P and the glutathione peroxidases. These antioxidant selenium-dependent enzymes protect mitochondrial function and sperm membranes against oxidative damage. Specifically, they catalyze the reduction of hydrogen peroxide and lipid hydroperoxides [Patel 2026]. read more

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Selenium and Mercury in the Fish We Eat

What should we know about eating fish and exposure to mercury in fish?
Fish and chips
Fish and chips. How careful should we be about eating fish? Which fish contain more harmful mercury than protective selenium? What should pregnant women know about eating fish during pregnancy?

Fact: Most fish contain mercury. Mercury is a toxic substance. Fortunately, most fish contain both selenium and mercury. On a molar basis, most edible fish contain more selenium than mercury. That makes it safe to eat most fish [Ralston 2024; Ralston 2016].

The selenium in fish binds tightly to mercury. The binding forms stable complexes that prevent mercury from damaging our cells. When there is more selenium than mercury (on a molar basis), this binding effectively neutralizes mercury’s toxicity. As a result, the mercury becomes biologically inactive and far less harmful when we eat the fish [Ralston 2023].

Even so, having just enough selenium available to neutralize the mercury exposure is not good enough. Logically, there must be a surplus of selenium. Without a surplus of selenium, there will not be enough selenium to synthesize antioxidant selenoenzymes. And, we need the antioxidant selenoenzymes to counteract the harmful free radicals in the brain. Providing more selenium, via supplementation if necessary, keeps selenoenzymes doing their antioxidant job. read more