Selenium is one of the few nutrients that directly controls how your body handles oxygen at the cellular level. Every time your cells produce energy, they generate peroxides as a byproduct. That Selenium, a Micronutrient That Modulates Cardiovascular Health via Redox Enzymology Selenium in thyroid function and repair Glenville Nutrition PDF) Structureactivity correlation between natural glutathione peroxidase ( GPx) and mimics: a biomimetic concept for the design and synthesis of more efficient GPx