(See also Nutrition in Infants.)
The only acceptable alternative to breastfeeding during the first year is formula; water can cause hyponatremia, and whole cow’s milk is not nutritionally complete. Advantages of formula feeding include the ability to quantify the amount of nourishment and the ability of family members to participate in feedings. But all other factors being equal, these advantages are outweighed by the undisputed health benefits of breastfeeding.
Commercial infant formulas are available as powders, concentrated liquids, and prediluted (ready-to-feed) liquids; each contains vitamins, and most are supplemented with iron. Formula should be prepared with fluoridated water; fluoride drops (0.25 mg/day po) should be given after age 6 mo in areas where fluoridated water is unavailable and when using prediluted liquid formula, which is prepared with nonfluoridated water.
Choice of formula is based on infant need. Cow’s milk–based formula is the standard choice unless spitting up, diarrhea (with or without blood), rash (hives), or poor weight gain suggests sensitivity to cow’s milk protein or lactose intolerance (extremely rare in neonates); then, a change in formula may be recommended. All soy formulas in the US are lactose free, but some infants allergic to cow’s milk protein may also be allergic to soy protein; then, a hydrolyzed formula is indicated. Hydrolyzed formulas are derived from cow’s milk, but the proteins are broken down into smaller chains, making them less allergenic. True elemental formulas made from free amino acids are available for the few infants who have allergic reactions to hydrolyzed formula.
Bottle-fed infants are fed on demand, but because formula is digested more slowly than breast milk, they typically can go longer between feedings, initially every 3 to 4 h. Initial volumes of 15 to 60 mL (0.5 to 2 oz) can be increased gradually during the first week of life up to 90 mL (3 oz) about 6 times/day, which supplies about 120 kcal/kg at 1 wk for a 3-kg infant.