Vitamins and Minerals Health Article

Minerals

Although vitamins generally receive more attention than minerals, the body actually needs larger amounts of certain minerals—called macrominerals—than the amounts of vitamins it requires to stay healthy. The seven macrominerals, all required in amounts of 100 mg or more a day, are calcium, magnesium, phosphorus, sodium, potassium, chloride, and sulfur. In addition, there are 10 microminerals, also called "trace elements," of which the body requires only very small amounts. These are cobalt, iron, zinc, iodine, copper, fluorine, manganese, chromium, selenium, and molybdenum. In spite of the small requirements for these minerals—in some cases considerably less than 1 mg—they are all needed if good health is to be maintained.

Iron, which plays an important role in carrying oxygen to the tissues, has long been the mineral best known to the general public because of its connection with anemia. Iron-fortified, multivitamin supplements have been popular for decades. Women are especially at risk for iron deficiency because iron is lost during menstruation, especially by women who bleed heavily. Good dietary sources of iron are red meat, liver, dark green leafy vegetables, and legumes. In addition, many foods are fortified with iron.

Calcium, which is necessary for healthy bones and teeth, is the body's most plentiful mineral, accounting for about 2% of the average person's body weight. This mineral is also needed for muscle contraction, blood clotting, and the release of neurotransmitters, which carry impulses throughout the nervous system. The main dietary sources of calcium are dairy products. Other good sources of calcium are green leafy vegetables, beans, and nuts. Many foods, including orange juice, breakfast cereal, and bread, are available fortified with calcium.

Zinc is an important mineral found in all the cells of the body. It is necessary for normal physical growth in children and is also known for promoting healing and fighting infections. Zinc deficiencies in pregnant women can interfere with normal fetal development. Animal products—especially meat and seafood—are the main dietary source of zinc. Magnesium, which activates over 300 of the body's enzymes, is needed for muscle relaxation. It is thought to reduce hypertension and lessen the damage from heart attacks. Selenium, another important mineral, is an antioxidant believed capable of preventing heart attacks and reducing the risk of certain types of cancer.

Children's vitamin and mineral requirements

The American Academy of Pediatrics recommends that children obtain the vitamins they need by eating a well-balanced diet rather than through nutritional supplements. The group has stated that "healthy children receiving a normal, well-balanced diet should not need vitamin supplements over and above the recommended dietary allowances." However, some physicians still recommend vitamins for children until they are eating solid foods.

Infancy. Low birth-weight babies (those weighing less than 5.5 lb [2.5 g]) may require supplements due to vitamin deficiencies. Newborn babies generally have low levels of vitamin K, and it is standard practice for physicians to provide injections of this vitamin. Physicians may recommend vitamin supplementation in infancy during periods of rapid growth, or due to certain dietary factors, such as the use of powdered milk or goat's milk. Vitamins A and D are often recommended for breast-fed babies. Because they go through periods of rapid growth, infants also have aspecial need for iron. Babies are born with reserves of iron, which are enhanced by natural iron from breast milk or iron supplements in formula. By the age of six months, the infant's diet should include cereal, meat, and other foods that contain iron. Physicians routinely test hemoglobin levels in infants at the age of nine months to check for anemia.

School age. Some experts believe that supplements can be beneficial for older children since many may not eat well-balanced diets, either because their parents do not provide them or because the children are finicky eaters. Supplements are often recommended for children on weight-reduction diets. Children in strict vegetarian families who do not receive animal protein from dairy products may have a greater than average need for vitamin supplements, especially vitamin B₁₂. Other situations that may make nutritional supplements necessary include dietary restrictions due to food allergies, and metabolic or other disorders. A study conducted at the University of Washington in Seattle and published in the Journal of the American Dietetic Association found that children between the ages of 3-½ and 9 are most likely to be deficient in folie acid and vitamin B 6. Iron and zinc—trace elements that promote normal growth—have also been cited as nutrients lacking in the diets of many children. All experts who recommend supplements emphasize the fact that in almost all cases they should be considered as insurance rather than as a substitute for an adequate diet.

Adolescence. Due to the rapid growth spurts and the bad eating habits that are common at this age, adolescents may develop some vitamin deficiencies. Teenage girls, in particular, may be deficient in iron.