Vitamin D
Some pediatricians are concerned that not all breastfed babies are receiving adequate amounts of vitamin D. This nutrient is particularly important in the first year of life to make sure bones are properly calcified during this period of rapid growth. Besides being contained in breastmilk, the vitamin is synthesized from sunlight. But many infants today are protected from the elements; parents may keep them covered up in the summertime, and indoors -- or at least bundled up -- in wintertime.

"Pollution may also curtail a lot of the UV light needed to make vitamin D," says Fima Lifschitz, M.D., chief of nutrition sciences at Miami Children's Hospital and a member of the American Academy of Pediatrics Committee on Nutrition. "Even where sun is plentiful, babies may not be exposed to sunlight as much as they should be." Dark-skinned infants are especially at risk, since they do not absorb sunlight through the skin as readily as fair-skinned children. For all these reasons, many pediatricians recommend that nursing babies receive vitamin drops containing vitamin D. (These drops usually also contain vitamins A and C, two other vitamins that may occasionally be lacking in breastfed infants.) Since prepared infant formulas are fortified with these vitamins, additional drops aren't necessary. 

Iron
Babies are born with enough stores of iron to last for four to six months... which is about the time they begin eating solid foods. While some pediatricians will recommend iron supplements or formula with iron early, many doctors wait until a child is close to six months of age. Because many children don't eat ideal diets, at that point physicians may recommend iron-enriched cereal, iron-enriched formula, or vitamin drops with iron. "Iron deficiency can have long-term consequences for children," says Dr. Lifschitz. "It can interfere with normal neuropsychological development."

Fluoride
This mineral is essential to the formation of strong, healthy teeth since it helps form tooth enamel which prevents decay. Fluoride is found naturally in foods like vegetables and grains, and is added to drinking water in some water supplies. But if your town doesn't have fluoridated drinking water, your baby should be given a liquid fluoride supplement to take each day. Since toothpaste also contains fluoride, be sure to use only a small pea-size amount when brushing your baby's teeth since too much of the mineral can actually damage the teeth.