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Does Breastfeeding Boost IQ?

Study Shows Breastfed Kids Score Better on Some IQ Tests

Breastfeeding and IQ: Test Results continued...

Kramer says the nonverbal and overall IQ test score differences were not statistically significant -- but just barely. He says the more important point is that he found an overall trend to improvement in the measures in the long-term or exclusively breastfed children.

Teachers rated the breastfed intervention group's reading and math better than the control group children.

"I think it's a modest effect," Kramer says. The IQ advantage for the long-term breastfed children, he says, is similar to what has been found in research for first borns vs. younger siblings.

"It's not the difference between a genius and a mentally retarded child," he says.

Breastfeeding and IQ: Breast Milk or Social Interaction?

Whether the boost in IQ is due to the breast milk itself -- such as healthy fatty acids or other substances -- or the physical and social interaction that is part and parcel of breastfeeding is unknown, Kramer and others say.

"A mother who breastfeeds is likely to spend more time with her child," he says, as well as read to them later and do other activities. "The amount of time, the closeness, the way she interacts with the kids, undoubtedly differs between breastfeeding and non-breastfeeding mothers."

The bulk of studies on the topic, he adds, have shown a positive link. One notable exception: a study published in 2006 in the British Medical Journal concluded that breastfeeding has "little or no effect on intelligence in children." The study involved more than 5,400 children.

Kramer says his study is sounder because of a more rigorous methodology.

Breastfeeding and IQ: Second Opinion

Not surprisingly, a spokesman for La Leche League International, which promotes breastfeeding, calls the new study findings "significant and valid." Not every paper or research study has found an association, says Lawrence M. Gartner, MD, a spokesman for the league and professor emeritus from the University of Chicago.

"But the huge majority of them do show a positive effect -- improvement in IQ and school performance."

"I think there is more and more evidence that points this way," says Dennis Woo, MD, chairman of the department of pediatrics at Santa Monica UCLA & Orthopaedic Hospital, who reviewed the study for WebMD. However, he wonders if cultural influences may play a role since the study was conducted in Eastern Europe, and if the same results would hold for U.S. breastfeeding mothers. Woo also works as a consultant for formula companies.

"We can't generalize [the findings] to all populations necessarily," agrees Jennifer Shu, MD, an Atlanta pediatrician and author of Heading Home with Your Newborn, published by the American Academy of Pediatrics. "But there is no downside [to breastfeeding]."

A slightly different interpretation of the findings is proposed by Ruth A. Lawrence, MD, chairwoman of the academy's section on breastfeeding and a neonatologist at the University of Rochester School of Medicine in New York.  "What the study says to me is, breastfeeding does not make your child smarter, it allows your child to reach full potential. If you have a child with chromosomal abnormalities and Down syndrome, for instance, and breastfeed, you are not going to make that child a genius. You are going to allow that child to reach his full potential." 

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