Selenium (AKA Brazil Nuts)

I'm now taking so many supplements that I'm starting to rattle, however the research continues and the latest discovery relates to Selenium. And it appears as though the jury is out.

When i received by sperm analysis results, the doctor suggested i should eat some brazil nuts and drink green tea, at the time i thanked him for his advice but in my head i was thinking 'no way that's going to make any difference'. Regardless, i started eating the brazil nuts, about a handful a day.

Brazil nuts are apparently extremely high in Selenium, which appears to be very important to the formation of sperm;

"..Selenium protects lipid shell encasing each sperm (prevents lipid peroxidation), which is especially important since sperm have a very delicate fatty acid composition."

Essentially it helps protect the sperm from free radicals.

According to the below supplement sheet, 6 large brazil nuts can contain a whole load of useful nutrients including Vitamin E, Zinc & Magnesium, but most importantly, they contain about 800% of the RDA for Selenium;

That's an extremely high dose of selenium for just 6 brazil nuts, so how many should i be eating exactly?

Well, it seems that nobody really knows for sure. Too little and there's no impact, too much and it can have a negative impact;

A study into a dose of just 0.2mg of Selenium combined with n-acetyl-cysteine (another antioxidant i haven't yet looked into) had a good result;

"after 26 weeks of Se supplementation the mean total sperm count, concentration, normal morphology percentage and motility increased from baseline relative to placebo treatment"

Good stuff, so how about a higher dose?

A study into a dose of 0.3mg Selenium alone had this to say;

"higher Se supplementation (300μg/ day orally) increased serum and seminal plasma Se concentrations but did not affect sperm Se, serum androgen concentrations or sperm parameters [22]. The lack of an increase in sperm Se suggests that testicular Se stores are unresponsive to dietary Se concentrations"

...No major impact. Ok so how about even higher?

This study tried a volume greater than 0.4mg and had this result;

"The fraction of motile sperm in the high-selenium group decreased by 32% by week 13 and ended 18% lower than baseline. Selenium concentrations changed in seminal plasma but not in sperm"

So it appears as though a high dose is a no-go. The studies show an increase in Selenium within the seminal plasma, but not the sperm itself... This suggests to me that the spermies just don't require that much selenium.

This summary sheet provides a good overview of the various Selenium studies out there, it essentially concludes that selenium is most effective at a low dose and combined with antioxidants, particularly vitamin E (which is also present in Brazil nuts).

So exactly how many brazil nuts should i be eating? This website suggests 6-8 brazil nuts can contain about 0.5mg of selenium. I need about half of that apparently, so from now on I'm going to eat just 3 brazil nuts a day for my selenium fix.