Babies Fatter from Cow Milk Formula?

Babies fed standard cow milk formula may grow fatter than those fed hypo-allergenic formula, according to a recent study.

The study, published this week in the journal Pediatrics by researchers from the Monell Chemical Senses Center, in Philadelphia, followed a blind clinical trial of 64 newborns. Infants were randomly assigned to two groups, one of which was fed traditional cow milk formula  (the most common type), while the other was fed hypo-allergenic formula. After 7 months, the weight of babies in the first group averaged two pounds over that of babies in the second group. Both formulas have the same amount of calories, and weight differences could not be attributed to length differences.This early difference in weight may predispose infants fed cow milk formula to obesity: "Numerous studies have shown that rapid rates of growth during first year are linked to obesity, metabolic syndrome [and] mortality" says Julie Mannella, Ph.D., principal author of the study.

Most common baby formulas, such as Similac or Enfamil, are based on cow milk. Hypo-allergenic (protein hydrolysate) formulas, such as Nutramigen or Alimentum, are also based on cow milk, but the proteins in the formula have been processed to be less likely to generate allergic reactions. Babies fed formula typically gain more weight than breastfed babies, although weight gain for babies fed hypo-allergenic formula in the study was similar to that of breastfed babies. Hypo-allergenic formula is significantly more expensive than regular formula. Medical authorities strongly recommend breastfeeding as a preferable alternative to formula feeding.

Should you switch to hypo-allergenic formula? The sample size in the study was small, and the cause of the discrepancy in weight gain was not clear. The principal investigator, Julie Manella, when asked, believes that is would be premature to switch on the basis of the study alone. However, suspicion of lactose intolerance would be a good reason to switch despite the price difference.

Research for the study was funded by the U.S. National Institute of Child Health and Human Development.

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Study Abstract in Pediatrics