For squishy, water-based creatures, we humans sure do need a lot of metal in our diets. There are all kinds of metals—known as essential minerals—that we have to eat. Metal ions are single atoms, not complex molecules, and they cannot be synthesized by any living thing. They must be ingested in food or water, and the list of ions that are essential for us includes cobalt, copper, iron, chromium, nickel, zinc, and molybdenum. Even magnesium, potassium, calcium, and sodium are technically metals, and we need substantial amounts of these minerals daily too.
