Translations:Mineral (nutrient)/18/en

Elements considered possibly essential for humans but not confirmed

Many ultratrace elements have been suggested as essential, but such claims have usually not been confirmed. Definitive evidence for efficacy comes from the characterization of a biomolecule containing the element with an identifiable and testable function. One problem with identifying efficacy is that some elements are innocuous at low concentrations and are pervasive (examples: silicon and nickel in solid and dust), so proof of efficacy is lacking because deficiencies are difficult to reproduce. Ultratrace elements of some minerals such as silicon and boron are known to have a role but the exact biochemical nature is unknown, and others such as arsenic are suspected to have a role in health, but with weaker evidence. In particular, trace arsenic seems to have a positive effect on some organisms, but so does lead, showcasing the uncertainty behind whether some trace elements are truly essential. Strontium is tolerated and is a component of some drugs, but it is not essential, only beneficial. Non-essential elements can sometimes appear in the body when they are chemically similar to essential elements (e.g. Rb⁺ and Cs⁺ replacing Na⁺), so that essentiality is not the same thing as uptake by a biological system.