ABSTRACT
Inorganic nutrients are minor components of animal and plant tissues, which remain in ashes after foods are incinerated.
Minerals are classied into major and minor or trace elements according to their presence in foods and the requirements of human being. Major elements are required in amounts higher than 100 mg day−1, and include calcium (Ca), phosphorus (P), sodium (Na), potassium (K), magnesium (Mg), chloride (Cl), and sulfur (S). Minor or trace elements are those required in amounts lower than 100 mg day−1. This group include iron (Fe), zinc (Zn), copper (Cu), iodide (I), manganese (Mn), selenium (Se), chromium (Cr), and silicon (Si). The requirements of all of them can oscillate in a more or less narrow range. Intakes lower or higher than the requirements are responsible for deciencies or toxicity, respectively. There is a third group of minerals called “ultratrace minerals,” which still do not have clearly dened biochemical roles and whose possible functions are being investigated. This group includes vanadium (V), tin (Sn), nickel (Ni), arsenic (As), and boron (B) (Miller 1996).
