COVID Strategy SeleniumMay 04, 2020
COVID-19 Strategy: Selenium
LIttle things sometimes turn out to be really big. You haven't heard of selenium very much as it's a pretty arcane little niche of medicine. There are about 25 selenoproteins in humans. Five of them play a pivotal role in making glutathione. Many of us take some selenium to make sure our thyroids can make T3 properly and the enzyme "deiodinase", a selenoprotein, is critical to that function. Selenium is a tiny atom, and in that context binds very tightly in its chemical bonds. That's what makes it useful in proteins to help do their enzymatic processes but also leads to vulnerability. Selenium binds heavy metals, pesticides, dioxins, PCBs, and all other sorts of gunk circulating in our polluted world. We can't measure those things easily, but when we try we can find them and we do indeed have them all around us.
Could you be selenium deficient? Well, yes! The symptoms are subtle and non-specific, but one of them is reduced immunity (hair loss, brain fog, fatigue, reproductive problems, low thyroid). And why are you deficient? Check the map attached here and notice that Wisconsin's soils are "very low". The food grown around us in the midwest just doesn't contain much selenium. Then, we have boatloads of leftover dioxins, PCBs, lead, and mercury in our environment: you are likely deficient.
And just why does this relate to COVID-19? Did you know that selenium plays a critical role in viral immunology? Yup! There is a clear association between other RNA virus morbidity and selenium status. So, let's look at China and the recent COVID-19 epidemic. China happens to have some of the widest variations of selenium concentrations in soil (and hence local food), and hence localized selenium deficiency, in the world. Wuhan happens to be in the middle of the lowest selenium soil concentrations in China.
Ok, now look at the relationship between selenium concentrations and COVID-19 survival in China. The "cure rate" in Hubei Province, where Wuhan is the capital, was 13.2% compared to 40.6% in the rest of China combined. The overall death rate was 3.0% in Hubei province, 0.6% in the rest of China combined. Inside Hubei province is a unique town, Enshi, where selenium intake is over the top. It happens to have a tiny niche of way too much selenium. Their intake is over 550 mcg a day. Their "cure rate" from COVID-19 was 36.4% compared to 13.1% for the rest of Hubein province. The intake between the two areas was 3.13 mg/kg per day compared to .55 mg per kilo - about a 6 fold difference. But just look at another deficient part of China, Heilongjiang Province, with low selenium and again, death rate of 2.6%, much higher than the rest of China and similar to Wuhan.
Has this caught your fancy? Of course. It is preliminary but intriguing. High selenium is also a problem and there is a dramatic U shaped curve of benefit and risk. Too much and you also get in trouble. All we can really say is that these dramatic associations fit with the prior known role and benefit of selenium in immune status.
WWW: What will work for me. Well, you get a lovely dose-response supply of selenium from Brazil nuts. Each nut has about 70-90 mcg of selenium, exceeding the 55 mcg per day considered a daily minimum need. Four to five a week and you boost your midwest meager selenium dose and get some tasty nuts. I bought a bag of Brazil nuts this week. I will be munching them for the next six months. (My problem is that I like them. I eat one, I eat 30 - so remember that case of toxicity, son.)
1. What is selenium? Answer: A very small, light metal central to the enzymatic activity of about 25 proteins in humans, 5 of which are necessary to make glutathione, our natural detox agent.
2. How much selenium do we get in our diet? Answer: In Wisconsin, very little. We don't know a statewide average. I have measured many patients and found them to be low if they aren't taking it. I plan to measure more.
3. What is the evidence that selenium will help COVID-19 response? Answer: just epidemiology and associations. Wuhan city, with low historical selenium concentrations, had 5-6 times the mortality compared to the rest of China. Now, look at the map of US selenium concentrationsand compare the mortality we are seeing in the news to the map. New York, Chicago, Detroit, and Boston are deficient. Texas is doing fine, thank you very much.
4. What happens if I take too much? Answer: OOOH! Don't. You can get in trouble. There is a dramatic U shaped curve of risk-benefit.
5. How do I navigate this? Answer: Get a blood test, when it's safe to get out. In the meantime, take a Brazil nut or two. You can probably safely take 200mcg pills that are widely available, 3-4 times a week. Then get a blood test.