Minerals are substances typically found in nonliving things such as rocks or metal ores. Although minerals also are found in plants and animals, they do not occur there naturally. Instead, plants sometimes take up minerals from the soil in which they are planted. Animals obtain minerals when they eat these plants.

Minerals are substances made up of structures of single atoms (elements). They are inorganic and typically do not feature the carbon, hydrogen and oxygen atom chains that are part of organic compounds. Unlike vitamins, minerals cannot be broken down into other substances and instead always retain their chemical identity.

The rate and extent to which minerals are absorbed and used (bioavailability) varies from mineral to mineral. Some foods have substances such as phytates or oxalates that bind chemically with minerals and prevent the minerals from being absorbed. In addition, the presence of certain minerals can prevent the absorption, metabolism or excretion of others. Certain foods may also help the body absorb certain types of minerals.

Minerals typically are named after their location of origin or after a descriptive feature, such as color. All minerals are categorized as one of two types:

• Major minerals. Required by the body in large amounts. The body maintains a steady supply of about 5 grams (g) of each of the major minerals and principal electrolytes. A person needs to consume about 250 milligrams (mg) a day of each of these minerals to keep supplies of the mineral steady and to make up for amounts that are naturally lost over the course of a day.
  
  
• Trace elements. Required by the body in tiny amounts. The body stores less than 5 g of each of the trace elements. A person needs to consume fewer than 20 mg a day of these trace elements to maintain steady levels in the body.

When a mineral enters the body, it is absorbed in the intestines and moved through the body or stored. Some minerals move directly into the bloodstream and are carried into cells. Other minerals attach to proteins and become part of the body structure.