Thursday, May 08, 2008

More Research on Breastfeeding and IQ

Update: I found a much better article on the same study. Check it out. I have a copy of the actual research article, so email if you'd like it.

Breast-Fed Children Smarter, Study Finds

By Will Dunham, Reuters
Posted: 2008-05-06 15:31:46
Filed Under: Health News, Science News

- A new study provides some of the best evidence to date that breast-feeding can make children smarter, an international team of researchers said on Monday. Children whose mothers breast-fed them longer and did not mix in baby formula scored higher on intelligence tests, the researchers in Canada and Belarus reported. About half the 14,000 babies were randomly assigned to a group in which prolonged and exclusive breast-feeding by the mother was encouraged at Belarussian hospitals and clinics. The mothers of the other babies received no special encouragement.

Those in the breast-feeding encouragement group were, on average, breast-fed longer than the others and were less likely to have been given formula in a bottle.

At 3 months, 73 percent of the babies in the breast-feeding encouragement group were breast-fed, compared to 60 percent of the other group. At 6 months, it was 50 percent versus 36 percent.

In addition, the group given encouragement was far more likely to give their children only breast milk. The rate was seven times higher, for example, at 3 months.

The children were monitored for about 6 1/2 years.

The children in the group where breast-feeding was encouraged scored about 5 percent higher in IQ tests and did better academically, the researchers found.

Previous studies had indicated brain development and intelligence benefits for breast-fed children.

But researchers have sought to determine whether it was the breast-feeding that did it, or that mothers who prefer to breast-feed their babies may differ from those who do not.

The design of the study -- randomly assigning babies to two groups regardless of the mothers' characteristics -- was intended to eliminate the confusion.


"Mothers who breast-feed or those who breast-feed longer or most exclusively are different from the mothers who don't," Dr. Michael Kramer of McGill University in Montreal and the Montreal Children's Hospital said in a telephone interview.

"They tend to be smarter. They tend to be more invested in their babies. They tend to interact with them more closely. They may be the kind of mothers who read to their kids more, who spend more time with their kids, who play with them more," added Kramer, who led the study published in the journal Archives of General Psychiatry.

The researchers measured the differences between the two groups using IQ tests administered by the children's pediatricians and by ratings by their teachers of their school performance in reading, writing, math and other subjects.

Both sets of scores were significantly higher in the children from the breast-feeding promotion group.

The study was launched in the mid-1990s. Kramer said the initial idea was to do it in the United States and Canada, but many hospitals in those countries by that time had begun strongly encouraging breast-feeding as a matter of routine.

The situation was different in Belarus at the time, he said, with less routine encouragement for the practice.

Kramer said how breast-feeding may make children more intelligent is unclear.

"It could even be that because breast-feeding takes longer, the mother is interacting more with the baby, talking with the baby, soothing the baby," he said. "It could be an emotional thing. It could be a physical thing. Or it could be a hormone or something else in the milk that's absorbed by the baby."

Previous studies have shown babies whose mothers breast-fed them enjoy many health advantages over formula-fed babies.

These include fewer ear, stomach or intestinal infections, digestive problems, skin diseases and allergies, and less risk of developing high blood pressure, diabetes and obesity.

The American Academy of Pediatrics recommends that women who do not have health problems exclusively breast-feed their infants for at least the first six months, with it continuing at least through the first year as other foods are introduced.

Thanks, Heather, for sharing this with me!!


Scott said...

Most likely selection bias in this study. One of the quoted researchers says of breastfeeding mothers, "They tend to be smarter. They tend to be more invested in their babies. They tend to interact with them more closely. They may be the kind of mothers who read to their kids more, who spend more time with their kids, who play with them more."

What is interesting is that the article later said "Kramer said how breast-feeding may make children more intelligent is unclear."

Umm, probably because of what he just said above about being smarter, more interaction etc.

So, does breastfeeding in an isolated environment make children smarter? Or, do parents who already are smarter and more interactive (who just so happen to breastfeed) make their children smarter?

LesleyH said...

Scott, the women were randomly assigned so its not selection bias in this exact study, but I think you are right in many ways. This article was badly written. I need to find the original research because I'm thinking it might be the journalist's fault, not the researcher's. Either way, its my opinion that part of the IQ increase is all those things associated with bfing (smarter moms who read to, cuddle, and spend more time with the babe)and the other part is the biological superiority of the breastmilk to formula. Yes, formula is forever changing and improving, but it is never exactly like breastmilk and is still missing some components. Formula is modified cow's milk (which is meant for baby cows)which is substantially different in composition to human breastmilk. Things have to added and subtracted and processed to make it useable for human infants. It is a nice invention for rare circumstances like when the mom is ill or passes away or other extenuating circumstances, but it disturbs and saddens me that it has become so commonplace. It may be convenient in some ways, but it is not the healthiest or most natural choice for our babies.

LesleyH said...

Oh, forgot to add, the problems with this study could be completely elliminated if women were randomly assigned (like they were in this study)initially, but then when the researcher goes to analyze the data, he or she should match the participants in the experimental condition (the encouraged to breastfeed ladies)with participants in the control condition (no encouragement either way)on traits like age, IQ, income, education so that those things can't be blamed and then see if there is really a difference in the babies' IQs between the 2 groups. I know, I'm a stats geek! But, at least I got something out of my Ph.D. classes:) Seriously, this would not be that hard to do. I guess I will just have to do the study myself!!!