The use of soy protein–based formulas in infant feeding has increased in recent years and now accounts for nearly 25 percent of infant formula marketed in the United States. For this reason, the Committee on Nutrition of the American Academy of Pediatrics (AAP) has updated a 1983 AAP review of soy protein–based formulas and made recommendations on their appropriate use. Even though the AAP strongly recommends breast milk as the ideal source of nutrition for infants, the AAP recognizes that most infants receive formula by the time they are two months old.

The most recent AAP statement on soy protein–based formula, published in the January 1998 issue of Pediatrics, discusses the composition of isolated soy protein–based formulas; their use in term and preterm infants, disorders of carbohydrate metabolism, and acute diarrhea and secondary lactase deficiency; the antigenicity of soy protein–based formulas; allergenicity of soy protein–based formulas; and the treatment of colic with soy protein–based formulas.

Recommendations

The following conclusions and recommendations have been excerpted from the AAP review:

• Isolated soy protein–based formulas are considered by the AAP to be safe and effective alternatives to provide appropriate nutrition for normal growth and development in term infants whose nutritional needs are not being met from maternal breast milk or cow's milk–based formulas. Isolated soy protein–based formula has no advantage over cow's milk protein–based formula as a supplement for breast-fed infants.

• Because soy protein–based formulas are lactose-free, they may be used in infants with galactosemia and inherited lactase deficiency.

• Physicians can recommend the use of isolated soy protein–based formulas for term infants whose parents prefer a vegetarian-based diet for their infants.

• Most previously healthy infants with acute gastroenteritis can be managed after rehydration with continued use of breast milk or standard dilutions of cow's milk–based formulas. Isolated soy protein–based formulas are indicated when lactose intolerance has been documented.

• The routine use of isolated soy protein–based formula has no proven value in the prevention or management of infantile colic. The AAP believes that parental counseling as to the cause and duration of colic can be more valuable than switching to soy formula. According to the AAP, most colic diminishes spontaneously between four and six months of age.

• The routine use of isolated soy protein–based formula has no proven value in the prevention of atopic disease in healthy or high-risk infants.

• Infants with documented enteropathy or enterocolitis induced by cow's milk protein frequently are as sensitive to soy protein and should not be given isolated soy protein–based formula routinely. They should be provided with formula derived from hydrolyzed protein or synthetic amino acid.

• Most infants with documented IgE-mediated allergy to cow's milk protein will do well on isolated soy protein–based formula.

• Soy protein–based formulas are not designed or recommended for preterm infants who weigh less than 1,800 g (4 lb). The AAP states that the newer cow's milk protein–based formulas designed for preterm infants are better.