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.