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Pronunciations deoxyribonucleic acid electrolytes epinephrine hemoglobin ribonucleic acid

Minerals are necessary for the normal functioning of the body's cells. The body needs large quantities of sodium, potassium, calcium, magnesium, chloride, and phosphate. These minerals are called macrominerals. The body needs small quantities of copper, fluoride, iodine, iron, selenium, and zinc. These minerals are called trace minerals.

Minerals are an essential part of a healthy diet. The recommended dietary allowance (RDA)—the amount most healthy people need each day to remain healthy—has been determined for most minerals. People who have a disorder may need more or less than this amount.

Consuming too little or too much of certain minerals can cause a nutritional disorder. People who eat a balanced diet containing a variety of foods are unlikely to develop a nutritional disorder or a major mineral deficiency, except iron or iodine deficiency. However, people who follow restrictive diets may not consume enough of a particular mineral. For example, vegetarians, including those who eat eggs and dairy products, are at risk of iron deficiency. Consuming large amounts (megadoses) of mineral supplements without medical supervision may have harmful (toxic) effects.

Some minerals—especially the macrominerals—are important as electrolytes. The body uses electrolytes to help regulate nerve and muscle function and acid-base balance (see Acid-Base Balance: Introduction). Also, electrolytes help the body maintain normal volume in its different fluid-containing areas (compartments). Electrolytes are dissolved in three main compartments: the fluid within the cells, the fluid in the space surrounding the cells, and the blood.

To function normally, the body must keep the concentration of electrolytes in its compartments within very narrow limits. The body maintains the concentration of electrolytes in each compartment by moving electrolytes into or out of the cells. The kidneys filter the electrolytes in the blood and excrete any excess in the urine to maintain a balance between daily intake and output.

If the balance of electrolytes is disturbed, disorders can develop. An electrolyte imbalance can occur when a person becomes dehydrated; uses certain drugs; has certain heart, kidney, or liver disorders; or is given intravenous fluids or feedings in inappropriate amounts.

To detect nutritional disorders or an electrolyte imbalance, doctors measure the levels of minerals in a sample of blood or urine.

Minerals Mineral Good Sources Main Functions Recommended Dietary Allowance for adults Safe Upper Limit Calcium Milk and milk products, meat, fish, eggs, cereal products, beans, fruits, and vegetables Required for the formation of bone and teeth, for blood clotting, for normal muscle function, and for normal heart rhythm 1,000 milligrams 1,200 milligrams for people older than 50 2,500 milligrams Chloride Salt, beef, pork, sardines, cheese, green olives, corn bread, potato chips, sauerkraut, and processed or canned foods Involved in electrolyte balance 1,000 milligrams — Copper Organ meats, shellfish (especially oysters), chocolate, mushrooms, nuts, dried legumes, and whole-grain cereals Used to form enzymes that are necessary for energy production, for antioxidation (protection against cell damage due to reactive by-products of normal cell activity called free radicals), and for formation of the hormone epinephrine, red blood cells, bone, and connective tissue 900 micrograms 10,000 micrograms Fluoride Saltwater fish, tea, coffee, and fluoridated water Required for the formation of bone and teeth 3 milligrams for women 4 milligrams for men 10 milligrams Iodine Seafood, iodized salt, dairy products, and drinking water (in amounts that vary by the iodine content of local soil) Required for the formation of thyroid hormones 150 micrograms 1,100 micrograms Iron As heme iron: Meats, poultry, fish, kidneys, and liver As nonheme iron: Soybean flour, beans, molasses, spinach, clams, dried fruit, and fortified cereals Required for the formation of many enzymes in the body Is an important component of muscle cells and of hemoglobin (which enables red blood cells to carry oxygen and deliver it to the body's tissues) 8 milligrams 18 milligrams for women younger than 50 (premenopause) 27 milligrams for pregnant women 9 milligrams for breastfeeding women 45 milligrams Magnesium Leafy green vegetables, nuts, cereal grains, and seafood Required for the formation of bone and teeth, for normal nerve and muscle function, and for the activation of enzymes 320 milligrams for women 420 milligrams for men — Phosphorus Milk, cheese, meat, poultry, fish, cereals, nuts, and legumes Required for the formation of bone and teeth and for energy production Used to form nucleic acids, including DNA (deoxyribonucleic acid) 700 milligrams 4,000 milligrams Potassium Whole and skim milk, bananas, tomatoes, oranges, melons, potatoes, sweet potatoes, prunes, raisins, spinach, turnip greens, collard greens, kale, other green leafy vegetables, most peas and beans, and salt substitutes (potassium chloride) Required for normal nerve and muscle function Involved in electrolyte balance 3.5 grams — Selenium Meats, seafood, and cereals (depending on the selenium content of soil where grains were grown) Acts as an antioxidant, with vitamin E, protecting cells against damage by free radicals, which are reactive by-products of normal cell activity Required for thyroid gland function 55 micrograms 400 micrograms Sodium Salt, beef, pork, sardines, cheese, green olives, corn bread, potato chips, sauerkraut, and processed or canned foods Required for normal nerve and muscle function Involved in electrolyte balance 1,000 milligrams 2,400 milligrams Zinc Organ meats such as liver, eggs, and seafood Used to form many enzymes and insulin Some Trade Names HUMULIN NOVOLIN Required for healthy skin, healing of wounds, and growth 15 milligrams —

Last full review/revision February 2003