(Helmholtz Zentrum München – German Research Center for Environmental Health) Exactly 200 years after the discovery of the trace element selenium, researchers at Helmholtz Zentrum München have shown for the first time why this chemical element is indispensable for mammalian life. As integral part of the enzyme GPX4, selenium protects a subset of neurons from cell death during postnatal development. The researchers reported these findings in the scientific journal 'Cell'.