What is a Mineral?

Minerals

At least 18 minerals have been identified as being essential factors in human nutrition.

Minerals are inorganic chemical elements not attached to a carbon atom. They are constituents of the bones, teeth, soft tissue, muscles, blood and nerve cells and act as catalysts for many biological reactions within the body. They also play a major role in the production of various hormones. Minerals are classified as major (where the body requires more than 100mg of a mineral each day) or minor (trace, the body requires less than 100mg daily).

The major minerals are calcium, phosphorus, potassium, sodium, chloride, magnesium and sulphur. The minor minerals are boron, chromium, copper, iodine, iron, manganese, molybdenum, selenium, silicon, vanadium and zinc.

Many minerals are essential parts of enzymes and they also participate actively in regulating many physiological functions, including the transport of oxygen to the body's 60 trillion cells, providing the stimulus for muscles to contract and in many ways guaranteeing normal function of the central nervous system.

As most minerals are widely available in foods severe mineral deficiencies are unusual in the Western world. Even so, there are a few exceptions. Iron deficiency is common in infants, children and pregnant women. Zinc and copper deficiencies are not uncommon either.

Boron

Boron is a relatively recently discovered trace element which influences the metabolism of nutrients involved in the maintenance of strong bones. It is a major player in calcium and magnesium metabolism and is needed for converting vitamin D to its active form. Recent research has revealed that boron is needed for the activation of oestrogen and also plays a role in the maintenance of healthy joints. Fruits and vegetables are the main dietary sources of boron, however, this is dependent on levels of boron in the soil. Some of the best food sources include almonds, dates, peanuts, prunes, raisins, soybeans and unprocessed honey.

Calcium

Calcium is the most abundant mineral in the human body. Its primary function is to help build and maintain bones and teeth, which it does in conjunction with phosphorus. In addition, calcium aids the process of blood clotting and regulates the passage of fluids through the cells. It is also related to the proper functioning of the heart and neuromuscular system. In children calcium deficiency is associated with rickets, bone deformities and growth retardation. Adult deficiency leads to osteomalacia (softening of the bones). Muscle spasms, cramps, hypertension and osteoporosis can sometimes be attributed to low calcium levels. Dairy products are the most popular dietary source of calcium, although good amounts can be found in many other foods including kale and other green vegetables, nuts, seeds, dried figs and canned fish with edible bones.

Chloride

Chloride is found primarily in extracellular fluids and is especially abundant in the secretions of the gastrointestinal tract and in cerebrospinal fluid. Small amounts are found in bone and connective tissue and lesser amounts in muscle and nerve tissue. In foods, body secretions, tissues and fluids, chloride is closely associated with sodium and water. There is no established minimum intake for Chloride because it is found in such abundance in food. Chloride is found in salt substitutes (potassium chloride), sea salt, table salt (sodium chloride).

Chromium

Chromium serves to potentiate the effectiveness of insulin, the hormone responsible for blood sugar control. Chromium also plays a role in lowering total cholesterol, LDL cholesterol and serum triglyceride levels and improve the LDL to HDL cholesterol ratio. The main symptom of chromium deficiency is glucose intolerance, characterised by raised insulin and blood sugar levels. The best food sources of chromium are meats and wholegrain products, however the refining of grains removes this important mineral. Using aluminium cookware lowers chromium levels in cooked foods.

Copper

Copper is found in all the tissues of the body. It assists in the formation of haemoglobin and red blood cells by aiding iron absorption. Copper also assists in the conversion of an amino acid to a dark pigment which colours the hair and skin. A large amount of molybdenum, zinc or sulphur in the diet is antagonistic to copper - having an adverse effect on its absorption. Copper is found in many foods. Oysters, shellfish and legumes are particularly rich sources.

Iodine

Iodine is a trace element that is an essential component of the thyroid hormone, thyroxine, which is the master regulator of metabolic reactions involved in oxidation. Thyroid hormone accelerates cellular reactions, increases oxygen consumption and basal metabolic rate and influences growth and development and energy metabolism. Foods from the sea, including all fish and seaweeds (like kelp) are rich sources of iodine. Although sea salt itself has very little iodine, some salt used commercially is iodised (has iodine added to it).

Iron

Iron, along with protein and copper, manufactures haemoglobin, the oxygen carrying pigment found in red blood cells. Several key enzymes in the body rely on iron, as does energy production and metabolism. Iron deficiency is the most common nutrient deficiency worldwide, with pregnant and breastfeeding women and the elderly being most at risk. A severe iron deficiency results in anaemia, characterised by extreme fatigue and pallor. Vitamin C enhances the absorption of iron by changing it to a form that is more readily usable by the body. Food sources of iron include nuts, seeds, egg yolks, molasses, meat, poultry, liver and fish. Plant sources and dairy products contain nonhaem iron, whereas the haemoglobin and myoglobin in animal sources provide haem iron. While nonhaem iron makes up over 85% of the iron in our diet, haem iron is more easily absorbed.

Magnesium

Magnesium is highly concentrated within the cells of the body. Approximately 60 percent is found in the bone, 26 percent in the muscle and the remainder is found in soft tissue and body fluids. Although calcium is the mineral most closely associated with bone health, magnesium has a major part to play as well. Magnesium is involved in muscle contraction and nerve function. Magnesium also activates the sodium-potassium pump in the cells. Arguably, its most important function is its essential role in the proper functioning of the entire cardiovascular system. The best dietary sources of magnesium include whole grains, nuts, seeds, legumes and green leafy vegetables.

Manganese

Manganese is an important activator for, and is part of many enzyme systems. It plays a part in protein synthesis and fatty acid metabolism, and is necessary for normal skeletal development and for pituitary gland activity. Good dietary sources of manganese include nuts, whole grains, dried fruit and green leafy vegetables.

Molybdenum

Molybdenum is essential as a component of several enzymes, including those involved with alcohol detoxification, uric acid formation and detoxification of sulphites. A deficiency in molybdenum has been linked to tooth decay and cavities. Where intake has been found in low levels, the cavity rate has been higher; and conversely, where it is higher, the cavity rate is lower. Good dietary sources of molybdenum include legumes and whole grains. The dietary concentration of molybdenum may vary according to status of soil that the grains and vegetables are grown in.

Phosphorus

Phosphorus is the second most abundant mineral in the body and is found in every living cell. The majority of it is found as calcium phosphate. It is involved in the proper functioning of both muscles and nerves and often works along with calcium. The healthy body maintains a specific calcium - phosphorus balance in the bones of two to one. Phosphorus levels are regulated primarily by urinary excretion. An imbalance between phosphorus and calcium can result in increased calcium loss, which leads to bone loss and potentially osteoporosis. Although phosphorus is widely distributed in many foods, meat and dairy products are the richest dietary sources.

Potassium and Sodium

Potassium and Sodium are known as electrolytes - mineral salts that conduct electricity when dissolved in water. They are involved with the balance of fluid within the body. Every cell contains a 'sodium pump', which ensures that potassium remains within the cell and sodium stays predominantly in the fluids outside of the cell. The pump also helps maintain the electrical charge within the cell. This is very important to muscle and nerve cells, and explains why a potassium deficiency affects muscle and nerves first.

The proper potassium and sodium balance in food is important. One of the most common problems is too much sodium in the diet, thus disrupting the balance. To ensure that enough potassium is being consumed, a natural diet rich in fruits and vegetables high in potassium is recommended. Potassium can also be found in unprocessed meats and fish.

Selenium

Selenium is an essential trace mineral that works synergistically with vitamin E. As a constituent of glutathione peroxidase, an antioxidant enzyme, selenium neutralises free radicals before they can damage body tissues. Keshan disease, a severe heart disorder, is seen amongst those with severe selenium deficiency and is common in certain areas of China, where the soil is lacking selenium. The selenium content of food varies greatly because of the wide variability of this element in the soil. Accurate levels in food are not available, however whole grains and Brazil nuts are classified as selenium-rich foods.

Silicon

Silicon is the most abundant mineral found on earth. Unfortunately, silicon's role within the human body has been poorly researched. However it is known to be essential for the integrity of the skin, ligaments, bones and tendons (all of which contain large amounts of silicon). The best dietary sources of silicon are whole grains such as oatmeal and brown rice, organ meats and root vegetables.

Vanadium

Vanadium is a trace mineral and antioxidant. Recent research on vanadium has led to suppositions about its role in controlling blood sugar levels and regulating cholesterol levels in the body. Dietary sources include beets, buckwheat, milk, oats and soybeans.

Zinc

Zinc is in every cell of the body and is a part of over 200 enzyme systems. Essential for the maintenance of vision, taste and smell, this mineral is also necessary for immune function, reproductive health, protein synthesis and cell growth. It is also required for the activity of antioxidant enzyme super-oxidise dismutase. Marginal zinc deficiency has been linked to decreased sense of taste and smell, eating disorders and impaired immune function. Good dietary sources of zinc include lean meat and poultry, eggs, fish, oysters, wheat bran soybeans and whole grains.