To improve diets and increase selenium levels , schoolchildren were fed a soup made of seaweed and pork bone that contained egg whites , yellow beans and iodine .
Gradually , the data suggested a number of possible connections : residents had extremely low amounts of selenium , a trace element necessary for cells to function normally .
He cited the glass industry , which has replaced its consumption of cerium with selenium over the past year as prices of the rare earth rose to $ 135 per kilo currently from just $ 3.88 per kilo in 2009 .