Minerals

The word mineral literally means 'mined from the earth'. They can be divided into two main groups, metallic and non-metallic elements. Carbohydrates, fats, proteins and vitamins are all based on the element, carbon, and are known as organic substances. Minerals do not contain carbon and are said to be inorganic. In nutritional terms, the word mineral refers to inorganic substances of which we need to obtain more than 100mg per day from our diet. Those needed in amounts much less than 100mg are referred to as trace elements - many of which are metals.

Carbohydrates, fats, proteins and vitamins are all based on the element, carbon, and are known as organic substances. Minerals do not contain carbon and are said to be inorganic. In nutritional terms, the word mineral refers to inorganic substances of which we need to obtain more than 100mg per day from our diet. Those needed in amounts much less than 100mg are referred to as trace elements -- many of which are metals.

Around 20 minerals and trace elements are essential for the biochemical reactions occurring in human metabolism. The average adult contains around 3kg of minerals and trace elements, most of which are found in the skeleton.

In general, the mineral content of foods depends on the soil in which produce is reared or grown. This is in contrast to the vitamin content of food, which is usually similar wherever it's produced in the world. Acid rain and food processing can also reduce the mineral content of foods enough to cause deficiency.

Although some vitamins can be synthesized in the body in tiny amounts, minerals and trace elements can only come from the diet. As a result, mineral deficiency is more common than vitamin deficiency, especially among slimmers, the elderly, pregnant women, vegetarians and those eating vegetables grown in mineral-poor soils.

The role of minerals in the body

Minerals have a number of roles in the body:

* Structural e.g. calcium, magnesium and phosphate which strengthen bones and teeth.
* Maintaining normal cell function e.g. sodium, potassium, calcium.
* Co-factor for important enzymes e.g. copper, iron, magnesium, manganese, molybdenum, selenium, zinc.
* Involved in oxygen transport e.g. iron.
* Hormone function e.g. chromium, iodine.
* As antioxidants e.g. selenium, manganese.

Some trace elements such as nickel, tin and vanadium are known to be essential for normal growth in only tiny amounts, although their exact roles is not yet fully understood.