Minerals are inorganic substances found in nonliving sources such as rocks and metal ores. Plants may obtain minerals from the soil, and animals may obtain them from eating plants.

All minerals are categorized as one of two types:

• Major minerals. Required by the body in large amounts. Examples include calcium, magnesium, phosphorus, sulfur, chloride, potassium and sodium.
  
  
• Trace elements. Required by the body in tiny amounts. Examples include chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium and zinc.

Minerals help to trigger or regulate many important body processes, including maintaining a proper fluid balance and playing a key role in muscle contractions and nerve impulses. Minerals also give structure to bones, teeth, muscles and blood.

Some minerals are extremely easy to obtain through a healthy, balanced diet. However, deficiencies of other minerals (e.g., calcium, iodine, iron, selenium and zinc) are more common. Symptoms of mineral deficiency vary, depending on the mineral that is lacking.

Consuming too much of some minerals also can lead to health problems including, in some cases, death. Minerals that may be toxic when taken in large amounts include calcium, fluoride, iodine, iron, magnesium, molybdenum, phosphorus, selenium and zinc.

Minerals are found in many different foods. Some foods contain more of a specific mineral than others. A well-balanced diet that incorporates foods from each of the five basic food groups (e.g., fruits, vegetables, grains, milk, meat/beans) is the best way to ensure an adequate supply of most of the major minerals and trace elements.

Many minerals also are available in supplement form. These may be recommended for some people under certain circumstances.