Most of us know that we need vitamins in our diet – vitamin C for good health, vitamin D to build bones, vitamin A for vision and skin and many others. Minerals and trace elements are equally as important, and the sophisticated machinery of the human body needs only microscopic amounts of these. What do minerals do for us?
Mention minerals and most people will think of mining, jewellery or one of the latest makeup fads. However minerals are also an essential part of the function of the human body, and thus have to be included in our food intake.
We have all seen the breakfast cereal advertisements mentioning that the food is ‘fortified with vitamins and minerals’- but what is the difference between the two? Vitamins are ‘organic’ compounds, which are made by plants or animals and so are passed to us when we eat plant or animal products. Minerals, as implied by the name, are found in the soil and are absorbed by plants or animals, not made by them. They then pass to us in the food chain.
Minerals are a vital catalyst for good health, as they are needed to help the body to metabolise food and to keep the bones and teeth strong. For example, most of us know that we need calcium for strong bones, and iron to help us produce the haemoglobin in our blood. This is the essential protein in our red blood cells and is vital to transport oxygen from the lungs to the body tissues. Iron deficiency is a very common cause of ill-health, while a rare metabolic disorder that leaves too much iron in the blood and can be equally harmful.
As well as the larger-scale minerals, the body also needs some trace elements, so-called because we need only tiny amounts. The total daily need for these elements is less than a thimbleful, but without these traces we are in trouble. As an example of how important these trace elements are, consider iodine which is used by the thyroid gland to produce essential growth hormones. Most people need about a thousandth of a gram of iodine a day, although pregnant women need twice as much; still a tiny amount. However if this is missing it can have catastrophic effects, especially on babies and children. The ugly term ‘cretinism’ was used in Victorian times to describe the results of iodine deficiency, which included mental retardation. This problem has surfaced in modern times in Australia, in hilly areas where the iodine leaches from the soil and thus does not get into the food chain. As a result it is now compulsory to use iodised salt in bread in Australia and New Zealand.
Other trace elements include those that you may remember from studies of the periodic table in school chemistry lessons. Elements essential in small doses include chromium, copper, selenium, cobalt, selenium and manganese. Some of these are toxic in higher doses, and so there is very rarely any need for supplements. Others are so important that they are added to our food and water –as well as iodine in salt, many countries add fluoride to tap water. Where this is done, the levels of tooth decay have dropped dramatically.
How can we make sure that we get all the minerals that we need? The good news is that we really don’t have to worry too much about this, because the human body has evolved to obtain almost everything that it needs for growth and health from everyday sources. A good balanced diet with plenty of fresh food will provide all nutritional needs for most people – only the very young, the ill or the elderly may need additional help. The major needs for calcium can be met with dairy products, fish and leafy green vegetables. Iron comes from red meat, pulses, fruit, wholegrains and more of those leafy green vegetables.
There is a thriving industry in mineral and trace element supplements, just as there is for vitamins. While some vitamin overdoses will simply be excreted, mineral supplements need to be treated with caution. Overdosing on minerals (generally caused by unwise use of supplements) can be harmful, with effects ranging from a simple stomach upset to irreversible damage to vital organs.
It is worth noting that some things that we eat and drink can interfere with the absorption of minerals. There is some evidence that caffeine interferes with the absorption of magnesium, and spinach also contains oxalate which actually stops the body from using the high levels of calcium and iron that are in the vegetable.
As always, the way to give your body the nutrition that it needs is very simple. Feed it a balanced and varied diet with plenty of fresh or minimally processed food, complement this with some exercise and you are most of the way to good health.