What Are Minerals?
Minerals are "inorganic" (they don't contain carbon) compounds that the body needs in very small amounts to perform a variety of functions.
What Types Of Minerals Are There?
Minerals are classified into two groups based on the body's need: Major minerals and Minor minerals
- Needed in amounts greater than 100 milligrams per day
- Include calcium, phosphorous, magnesium, sodium, potassium, chloride, and sulfur
- Like fat-soluble vitamins, excess amounts of minerals are stored in the body and can gradually build up to toxic levels. An excess of one mineral can also interfere with the functioning of others.
- Needed in amounts less than 100 milligrams per day (hence called "trace" minerals)
- Include iron, manganese, copper, iodine, zinc, cobalt, fluoride, selenium
fat-soluble vitamins, excess amounts of minerals are stored in the body
and can gradually build up to toxic levels. An excess of one mineral
can also interfere with the functioning of others:
- High iron intake can produce an iron overload (hemochromatosis) in genetically predisposed people and cause deficiencies of other trace minerals (zinc and copper). If left untreated, iron overload can damage the liver, pancreas, and heart.
- Excess zinc consumption may reduce HDL ("good") cholesterol levels, impair immune function, and inhibit copper absorption from foods, possibly leading to anemia.
- In susceptible people, excess calcium can increase the risk of kidney stones; excess calcium from diet or supplements may also interfere with the absorption of iron.
- Copper supplementation isn't recommended as athletes aren't usually copper deficient and there is no evidence to suggest copper enhances athletic performance.
- Selenium supplementation isn't recommended as most people get enough selenium and an excess intake may be harmful.
What Do Minerals Do?
- Some minerals, such as calcium and phosphorus, are used to build bones and teeth. Others are important components of hormones, such as iodine in thyroxin. Iron is critical to the formation of hemoglobin, the oxygen carrier within red blood cells. Minerals also contribute to a number of the body's regulatory functions, including regulation of muscle contractions, conduction of nerve impulses, clotting of blood, and regulation of normal heart rhythm.
- For a table listing the function and sources of most minerals, click here.
How Can I Be Sure My Child Gets Enough Minerals?
Here's what you can do to make sure your child gets all the minerals he or she needs:
- Make sure he or she is eating a healthy, well-balanced diet that includes the foods and servings recommended in the Food Guide Pyramid. For a list of the vitamins and minerals in commonly eaten foods, click here.
- Make sure your child gets enough iron. Since most of the oxygen transported in the blood is bound to the iron in hemoglobin, iron-deficiency anemia (the nation's most common nutritional deficiency) adversely affects athletic performance by reducing maximum aerobic capacity and endurance. Girls, especially after they reach puberty and start menstruating, tend to consume less iron than the RDA recommends. This is especially true in the "aesthetic" sports (gymnastics, diving, ballet, figure skating) where girls tend to restrict calories to maintain a lower body weight. If iron supplements are necessary, they shouldn't exceed the RDA unless medically indicated and prescribed by a doctor. For a table listing food sources for iron, click here.
- Make sure your child consumes the recommended amount of calcium to promote optimal bone health (The AI values for calcium are 800 milligrams per day for children 4 to 8 and 1,300 milligrams for children and adolescents 9 to 18). Female adolescents who have a poor calcium intake are a special concern because they may be setting themselves up for an increased risk of osteoporosis, an age-related disorder in which the bone mass decreases and the susceptibility to fractures increases. For a list of food sources for calcium, click here.
- If you want "nutritional insurance," make sure your child eats more nutrient-dense foods , especially nutrient-dense grain products, fruits vegetables, and legumes, and fewer empty calories in high-sugar and/or high fat snacks. For some ideas for helping your child eat more fruits and vegetables, click here.
- For athletes who limit their calorie intake because they compete in sports that emphasize leanness for enhanced performance (distance runners, lightweight crew, wrestlers) or for appearance (gymnasts, dancers, figure skaters, divers) are at risk for nutritional deficiencies and may benefit from a vitamin/mineral supplement supplying 100% of the RDA or AI.
- If your child is consistently unable to incorporate certain foods into the diet, is chronically on a very-low calorie diet, is a vegetarian, or has malabsorption problems, a one-a-day multivitamin and multi-mineral (100% of the RDA) is prudent to ensure adequate intake of micronutrients.
- If your child does not fall into one of these categories and is consuming a healthy, well-balanced diet, most experts agree that there is no harm in taking a simple vitamin/mineral supplement, provided it does not exceed 100% of the RDA or AI for nutrients (although there is no evidence that such supplementation is beneficial, either).
If you do decide to have your child take a vitamin/mineral supplement, look for: products with USP (United States Pharmacopeia) on the label, which means that the manufacturer is legally responsible to the Food and Drug Administration (FDA) for meeting USP dissolution standards for how well the supplement dissolves and that the supplement has undergone a battery of other tests as well - for disintegration, strength (potency), and purity.