Minerals Health Article

Definition

Minerals are naturally occurring inorganic substances that are obtained from food and perform a range of important functions in the body. Minerals are categorized as major minerals, or macronutrients, which are present in the body in amounts greater than five grams; and trace minerals, which are present in amounts below five grams. Trace minerals are sometimes called micronutrients.

Major minerals

The major minerals consist of calcium, phosphorus, potassium, sulfur, sodium, chloride, and magnesium. Sodium, potassium, and chloride are sometimes grouped together as electrolytes. An electrolyte is a substance that breaks down into ions when it is dissolved in a suitable medium and thus becomes a conductor of electricity. Each of the major minerals aids in maintaining the body's fluid, electrolyte, and acid-base balance as well as having specific functions.

CALCIUM. Calcium is the most abundant mineral in the human body; 99% of it is stored in the bones and teeth. Calcium maintains bone structure and helps regulate blood calcium levels. This mineral is also necessary for the transport of electrical ions across cell membranes. Inadequate calcium intake during childhood and adulthood can result in osteoporosis, in which there is loss of bone substance. Many Americans do not get enough calcium in their diets. Good dietary sources of calcium include milk, broccoli, mustard greens, kale, cheese, and sardines. The recommended dietary allowance (RDA) of calcium for adults is about 800 mg.

PHOSPHORUS. Phosphorus is also an abundant mineral. Most of the phosphorus—about 80%—that occurs in the body is combined with calcium in the bones and teeth. Phosphorus plays a role in the energy metabolism of cells; helps maintain the body's acid-base balance; and is needed for tissue growth and renewal. Animal products that are high in protein, such as milk, cottage cheese, and steak, are excellent sources of phosphorus. Deficiencies of phosphorus are rare except in patients taking antacids for long periods of time. The RDA of phosphorus for adults is 800 mg.

MAGNESIUM. About 50% of the body's magnesium is in the bones, with the remainder in the cells of the muscles and soft tissues. Magnesium functions in the operation of enzymes and aids in the metabolism of calcium, potassium, and vitamin D. Magnesium deficiency can result from a low intake of the mineral, from diarrhea, and from alcoholism. Magnesium deficiency can cause hallucinations and has been associated with heart problems. Good dietary sources of magnesium include spinach, oysters, baked potatoes, and sunflower seeds.

Magnesium is used in a number of over-the-counter preparations as an antacid and laxative. The most common uses of magnesium in clinical medicine include treatment of tachycardia (excessively rapid heartbeat), and depletion of electrolytes (chloride, potassium, and sodium). It is also used to manage premature labor. The RDA of magnesium is 350 mg for men, 280 mg for women.

SODIUM. Sodium is a mineral that plays an important role in the proper functioning of nerves and muscles. It is also an important component of intracellular fluid. Sodium deficiency does not occur with a normal diet, but may result from illness or injury. Too much sodium in the diet may raise blood pressure and cause hypertension. Salt is the main source of sodium in the diet, but table salt is not the most significant source of sodium. Most sodium in the average American's diet comes from processed and fast foods. The RDA of sodium is between 100 and 3300 mg.

POTASSIUM. Potassium helps maintain fluid and electrolyte balance in the body. Potassium is found in a variety of foods; however, potassium deficiency can result from illness, injury, or treatment with diuretics. The best sources of dietary potassium are fresh fruits and vegetables, especially bananas, potatoes, and raisins. The RDA of potassium is between 1875 and 5625 mg.

CHLORIDE. Chloride helps maintain fluid balance in the body. It is an essential component of the hydrochloric acid in the gastric fluid required for digestion. Chloride deficiency can result from repeated vomiting, diuretic therapy, or kidney disease. The RDA of chloride is between 1700 and 5100 mg.

SULFUR. Sulfur occurs in the body in such other compounds as thiamine and proteins. It helps to maintain the structure of skin, hair, and nails, and functions in oxidation/reduction reactions. Sulfur deficiency is a relatively unusual condition, because the body's need for sulfur is satisfied by the amino acids contained in foods high in protein.