Bone mineral content of infants fed soy-based formula.

We compared the results of two studies that measured the bone mineral content (BMC) of 57 infants fed soy-based formula and 27 infants fed human milk or cow milk-based formula at various ages from 2 weeks to 1 year. In a study by Chan et al., the BMC of 40 white infants fed soy-based formula and 10 infants (of unstated race) fed human milk was measured at 2 weeks and at 2 and 4 months of age. The infants fed soy-based formula also had BMC measured at 6 and 12 months; the BMC of these infants was compared to the BMC of human milk-fed historical control subjects. The BMC was similar at 2 weeks in both groups but was lower in infants fed soy-based formula than in human milk-fed infants at 2 and 4 months. The BMC was similar in historical control subjects fed human milk and in soy formula-fed infants at 6 and 12 months. In the Steichen-Tsang study, the BMC of 17 soy formula-fed infants and of 17 white infants fed cow milk-based formula was measured at 6 weeks and at 3, 6, and 12 months of age. The BMC was similar at 6 weeks in both groups but was lower in infants fed soy-based formula than in those fed cow milk-based formula at 3, 6, and 12 months. The BMC of the historical control group fed human milk and of the soy formula-fed infants was also similar. In the first year of life, the BMC of infants fed soy formula and those fed human milk appears to be similar, especially after 6 months of age. However, the BMC of infants so fed may be lower than that of infants fed cow milk-based formula.