A substance that is neither animal nor vegetable; inorganic matter.

 

An inorganic element, such as calcium, iron, potassium, sodium, or zinc, that is essential to the nutrition of humans, animals, and plants.

 

Minerals are used in treatments by three methods, namely, by replacing a poor diet with a diet that supplies the RDA, by consuming oral supplements, or by injections or infusions. Injections are especially useful for infants, for mentally disabled persons, or where the physician wants to be totally sure of compliance. Infusions, as well as injections, are essential for medical emergencies, as during mineral deficiency situations like hyponatremia, hypokalemia, hypocalcemia, and hypomagnesemia. Oral mineral supplements are especially useful for mentally alert persons who otherwise cannot or will not consume food that is a good mineral source, such as meat. For example, a vegetarian who will not consume meat may be encouraged to consume oral supplements of iron, as well as supplements of vitamin B12.

Iron treatment is used for young infants, given as supplements of 7 mg of iron per day to prevent anemia. Iron is also supplied to infants via the food industry's practice of including iron at 12 mg/L in cow milk-based infant formulas, as well as adding powdered iron at levels of 50 mg iron per 100 g dry infant cereal.

Calcium supplements, along with estrogen and calcitonin therapy, are commonly used in the prevention and treatment of osteoporosis. Estrogen and calcitonin are naturally occurring hormones. Bone loss occurs with diets supplying under 400 mg Ca/day. Bone loss can be minimized with the consumption of the RDA for calcium. There is some thought that all postmenopausal women should consume 1,000–1,500 mg of calcium per day. These levels are higher than the RDA. There is some evidence that such supplementation can reduce bone losses in some bones, such as the elbow (ulna), but not in other bones. Calcium absorption by the intestines decreases with aging, especially after the age of 70. The regulatory mechanisms of the intestines that allow absorption of adequate calcium (500 mg Ca/day or less) may be impaired in the elderly. Because of these changes, there is much interest in increasing the RDA for calcium for older women.

Fluoride has been proven to reduce the rate of tooth decay. When fluoride occurs in the diet, it is incorporated into the structure of the teeth, and other bones. The optimal range of fluoride in drinking water is 0.7-1.2 mg/L. This level results in a reduction in the rate of tooth decay by about 50%. The American Dental Association recommends that persons living in areas lacking fluoridated water take fluoride supplements. The recommendation is 0.25 mg F/day from the ages of 0-2 years, 0.5 mg F/day for 2-3 years, and 1.0 mg F/day for ages 3-13 years.

Magnesium is often used to treat a dangerous condition, called eclampsia, that occasionally occurs during pregnancy. In this case, magnesium is used as a drug, and not to relieve a deficiency. High blood pressure is a fairly common disorder during pregnancy, affecting 1-5% of pregnant mothers. Hypertension during pregnancy can result in increased release of protein in the urine. In pregnancy, the combination of hypertension with increased urinary protein is called preeclampsia. Preeclampsia is a concern during pregnancies as it may lead to eclampsia. Eclampsia involves convulsions and possibly death to the mother. Magnesium sulfate is the drug of choice for preventing the convulsions of eclampsia.

Treatment with cobalt, in the form of vitamin B12,is used for relieving the symptoms of pernicious anemia. Pernicious anemia is a relatively common disease that tends to occur in persons older than 40 years. Free cobalt is never used for the treatment of any disease.
 

The following discussion describes the role of the major minerals in human nutrition.

Iron is essential for the formation of hemoglobin, the chemical in the blood that carries oxygen to the cells. Low levels of iron cause anemia. In severe cases, the children become flabby, and they fail to grow normally. Milder cases of iron deficiency may not produce any physical symptoms, but children may learn at a slower pace than children with a proper amount of iron in their diet. The combination of rice, beans, and meat consumed with fresh citrus fruit provides an excellent source of absorbable iron. Iron supplements are suggested for children who cannot or will not follow a proper diet through the first two years of life.

Calcium is required for proper development of bones and teeth. It is also needed for proper muscle activity and blood clotting. Lack of calcium can cause rickets, a condition in which the bones are soft and develop in abnormal shapes. Calcium must be accompanied by vitamin D in order to have the proper effects. Foods rich in calcium include almonds, swiss cheese, collards, sardines and salmon with bones, spinach, ice cream, kale, beet greens, cheddar cheese, molasses, oysters, milk, and broccoli.

Zinc deficiency has been associated with reduced growth and mental retardation. The best foods for zinc are lamb, beef, leafy grains, root vegetables such as potatoes and carrots, shellfish, and organ meats such as liver or kidneys. While a high fiber diet is important for health, too much fiber can reduce the absorption of zinc and lead to a zinc deficiency.

Iodine is needed in the diet for proper thyroid function. The best source of iodine is fish, but table salt normally has iodine added to it, and even modest amounts of salt will meet the daily iodine requirements.

Fluoride is needed for strong teeth. In many areas, drinking water contains fluoride that meets all normal needs, but for children who do not drink water or drink filtered or bottled water, fluoride supplements may be useful. Fluoride supplements may be useful for infants and then may be discontinued as the child gets older and starts drinking water.

Magnesium is found in so many parts of the body that it is almost impossible to describe the effects of low magnesium levels. The most common problems are twitching, and, because of the need for magnesium in the parathyroid gland, soft bones even when calcium and vitamin D are adequate. Because magnesium is found in most foods, deficiency is usually associated with absorption problems and requires medical attention.

Copper is required for blood and nerve fiber development. It is found in liver, nuts, and seafood.

Phosporus is needed for energy production, metabolism, and healthy bone development. The best sources are milk, cheese, meats, whole grains, eggs, peas, and beans.

Potassium is needed for muscle contractions and nerve function. Good sources of potassium are orange juice, milk, cheese, whole grains, and vegetables.

Selenium is needed for proper thyroid function. It has also been associated with prevention of some types of cancer in adults. Selenium supplements are not normally required except in children with phenylketonuria receiving a low-protein diet, although it may sometimes be associated with thyroid problems. In these cases, medical care is required.

Precautions

Although the greatest nutritional concern is with inadequate levels of minerals, it is possible to take too much, particularly when people already eating a normally healthy diet take supplements. The daily intake of minerals should be reviewed to prevent adverse effects.

Excess calcium may lead to constipation and kidney problems. Too much zinc may lead to diarrhea, vomiting, and kidney and heart problems. Excess iron may cause problems of the stomach and digestive tract, liver problems, an increased risk of diabetes, and male sexual problems.

Side Effects

When minerals are taken properly, they have no side effects.

Interactions

Minerals can interact with drugs and in excess with each other. Iron and calcium are known to bind to drugs of the tetracycline family and inactivate the antibiotic. The compound of calcium and tetracycline may also be absorbed into a child's teeth, causing discoloration.

Too much calcium in the diet may inhibit absorption of iron, magnesium, phosphorus, and zinc. Excess iron may reduce the absorption of zinc.

Parental Concerns

Following a proper balanced diet is the best prevention of both mineral deficiency and mineral overdose. Since many children and adolescents cannot or will not eat a balanced diet, the possible need for supplements should be discussed with an appropriate professional.

Many children fail to follow a proper diet. This may be because of excess intake of fast foods and snack foods of low nutritional value. It is important for parents to teach children the benefits of proper nutrition and the importance of maintaining a healthful diet.

At the same time, adolescents, particularly those who engage in sports, may feel that they will do better with increased levels of nutrients. Because of the risk of toxic reactions to minerals and some vitamins, children should be discouraged from taking vitamin supplements unless there is clear evidence of increased need.