MINERALS

A well balanced diet contains all the minerals necessary to maintain a fit and health body.

Minerals are an essential part of the diet, and they perform various functions.

Chemists divide all the natural substances in the world into two different types of chemical the organic and the inorganic. Organic chemicals, which are the ‘building blocks’ of life, contain the three main chemical elements of: carbon, oxygen and hydrogen plus lesser elements such as nitrogen. All the organic chemicals contain carbon. In contrast the inorganic chemicals do not depend on carbon and they consist of any compound of the remaining 91 naturally occurring elements.

When we speak of minerals in the diet, we are really talking about the few inorganic substances that are necessary for health in addition to the large amounts of organic carbohydrate, protein and fat that make up most of the diet. The vitamins, which are essential to diet, are organic compounds.

WHAT DO MINERALS DO ?

There are two different sorts of minerals in the body – those which are found throughout the tissues and cells where they are an essential part of a single key process. In the first category there are three main substances: sodium, potassium and calcium. They are all metals in their purified forms, but in the body they are in the form of salts.

This group of metal salts – perhaps with the addition of magnesium, is essential in different types of processes. There is considerable energy expanded by the body in controlling all of the functions. For example, the amount of sodium that is found in the fluid surrounding the cell is much greater than that within the cell membrane; with potassium the reverse is the case. This basic imbalance establishes a tension that is responsible for living cells being able to respond to stimulus. Many essential activities are electrical – muscle contraction (including the heartbeat) and nerve conduction are examples. About 70 per cent of the oxygen that we use to provide energy is needed to keep the sodium and potassium the right side of the cell membranes.

Calcium is the most abundant mineral in the body and it is an essential ingredient in building a healthy bone structure. Exercise is essential to achieve the right balance of calcium in the body and people who are bedridden, for example, are exercised as much as possible to reduce the risk of fractures.

In contrast, the other minerals may only be required for a few specific purposes in the body. Iron, for example, is an essential component of hemoglobin which carries the oxygen from the lungs to the tissues, while iodine’s only role is in the thyroid hormone – this exerts a great deal of control over the production and use of energy by the tissues.

WHAT CAN GO WRONG ?

The essential minerals are found in the soil and are therefore present in vegetables and animal foods. The two minerals which are most likely to be deficient in natural circumstances are iron and iodine. Iron deficiency (anaemia) is extremely common in underdeveloped countries where diet is inadequate. Even in developed countries there are some women who are anemic because of the iron they lose each month during their periods. Iodine deficiency is avoided by adding it to table salt.

There are complex systems to control the levels of sodium, potassium and calcium in the body. Although we think of the kidney as the organ for the disposal of waste material, most of the energy that it uses is in fact taken up in making sure that too much sodium and potassium are not lost in the urine.

Deficiencies of the other minerals are very uncommon and it is actually more common to encounter poisoning with minerals like manganese and copper. Copper poisoning – Wilson’s disease results from an inherited defect in the way that the body absorbs and stores copper. Zinc deficiency does occur though, and sometimes leg ulcers that old people develop can be helped by extra zinc.