by Amy Spangler
April 21, 2009

Breastfeeding’s purported lack of advantage over formula-feeding was the subject of a recent article by Hanna Rosin published in The Atlantic. While there is much to criticize in Rosin’s essay (see here and Case Against Breastfeeding Overlooks Big, Dirty Secret), there is also an element of truth (see The Case Against Breastfeeding (?)) in what Rosin has to say.

Because science was, is, and always will be imperfect, we rely upon the preponderance of evidence to guide our decision-making. Given that fact, even Rosin would have a hard time denying the growing body of evidence showing breastfeeding’s advantage over formula-feeding.

Smoking and its effects on breastfeeding
Researchers from the Netherlands recently found that breastfeeding may modify the harmful effects of smoking during pregnancy. Does this mean that women can smoke freely during pregnancy as long as they breastfeed? Absolutely not. But it’s further evidence of breastfeeding’s benefits.

A total of 570 infants (388 formula-fed and 182 breastfed) born between 1975 and 1978 participated in the study. Children who were breastfed for only one or two weeks or who were breastfed and bottle-fed were excluded from the study. Type of feeding was assessed on discharge from the hospital and retrospectively when the children were 9 and 25 years old. (The reliability of long-term recall of breastfeeding has been well-established in previous studies.) Reading, spelling, and arithmetic performance were assessed when the children were 9 years of age using standardized tests.

Study results
There was a significant difference between the two groups, with the formula-fed children scoring lower on the performance tests compared to the breastfed children. After controlling for socioeconomic status, marital status, and gender, the differences persisted. The researchers suggested several possible explanations:

• Women who breastfeed may parent their children differently than women who formula-feed, providing opportunities for learning that bottle-feeding women may be less likely to provide.

• Psychological factors may play a role. The interaction that takes place between a mother and a child while breastfeeding might explain the beneficial effect on school performance.

• There may be something in human milk that positively affects brain development and counteracts the negative effects of smoking.

As with most findings, more research is needed. But the take-home message is clear: Mothers who smoke should be encouraged to breastfeed.