Antioxidant and Selenium

Antioxidant noun - Substance that inhibits oxidation or inhibits reactions promoted by oxygen or peroxides.

Selenium and antioxidant are semantically related. In some cases you can replace term "Selenium" with "Antioxidant", this nouns are similar.

Selenium noun - A toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable grey metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite).

Antioxidant and selenium are semantically related. You can use "Antioxidant" instead a noun "Selenium".