Coronavirus: Chinese scientists find selenium may be a dirty secret behind low infection rates
- Researchers delve into theory that high selenium presence in the soil corresponds with higher human immunity
- But scientists say more research is needed and warn of dangers associated with excessive intake and taking selenium without medical advice
The city in western Hubei province recorded six Covid-19 cases per 100,000 residents. Elsewhere in Hubei, infection rates were between two and 20 times higher. Scientists had no clue why the coronavirus spared Enshi until speculation formed last year that the answer might be in its soil.
A new study by Chinese scientists published this week supported the theory and found “human selenium levels may contribute to antioxidant, anti-inflammatory and immune effects in Covid-19”.
Enshi has the world’s largest deposit of selenium, a non-metal trace element sitting next to deadly arsenic on the periodic table. The concentration of selenium in Enshi’s natural environment was so high that overexposure caused some local residents to lose their hair or fingernails.
But “relatively high dietary selenium intake in selenium-rich areas can enhance human immunity … [and] contribute to resisting Sars-CoV-2”, said a team led by Professor Ma Jin of the State Key Laboratory of Environmental Criteria and Risk Assessment at the Chinese Research Academy of Environmental Sciences in Beijing. The team’s paper was published in Environmental Research journal on Sunday.
As selenium levels dropped, the infection rate soared, Ma and colleagues found in data collected from cities across Hubei. Suizhou and Xiaogan, for instance, had the worst selenium deficiency and their positive case rates were the highest outside Wuhan, the provincial capital and home of the first-reported outbreak in China.