Some Baby Formulas May Cause Faster Weight Gain

http://www.npr.org/2011/01/24/133110606/some-baby-formulas-may-cause-faster-weight-gain

Although breast milk is the best food choice for infants, most American babies are fed formula at some point. It has been shown that these babies gain weight more rapidly than breast-fed babies.

The problem is that formula-fed babies often gain too much weight. This trend can continue throughout life, according to Nicolas Stettler, a pediatrician with Children's Hospital in Philadelphia.

Stettler points to studies both in the U.S. and Europe that show rapid weight gain, including a study at his hospital, which showed infants who experienced rapid weight gain during the first four months of life were five times more likely to be obese by age 20.

And, as children, Stettler says, there are more associated health problems, including liver abnormalities along with elevated blood sugars and high cholesterol.

Scientists at the Monell Chemical Senses Center in Philadelphia wanted to explore average weight gain with different formulas. They compared cow's milk-based formula to protein hydrolysate formulas, which contain predigested proteins and are typically fed to infants who cannot tolerate the intact proteins in other formulas.

Lead author and developmental psychobiologist Julie Mennella compared infants fed cow's milk formula to those fed the broken-down protein formula. After seven months, infants fed cow's milk formula had, on average, gained 2 pounds more than infants fed protein formula.

Mennella says the slower weight gain among infants on the predigested protein-based formula mimicked the average weight gain among breast-fed infants.

"There's something in cow-milk formula, or something lacking in cow-milk formula, that's resulting in babies overfeeding," she says. "I could give the same baby cow-milk formula one day and protein hydrolysate formula on the other, and that baby will satiate sooner and consume less formula on the protein hydrolysate day."

Mennella's study didn't explore the reasons for this, but she has some ideas. In adults, predigested proteins are believed to act in the intestine to initiate the end of a meal, leading to smaller meals and the intake of fewer calories. It could be these infants responded similarly, getting the full message to the brain sooner than infants fed cow's milk formula.

Stettler says the findings suggest certain formulas normalize weight gain, but says more research is needed — particularly over the long term because babies who gain weight too slowly are also at risk.

These infants "have less neurological development and attain a lower IQ during childhood and adulthood," he says, adding that parents, until further research provides conclusive answers, should work closely with their pediatricians to monitor their babys' weight and make sure they don't gain too much or too little. In this case, "average" is definitely best.