If last week’s headlines about breastfeeding gave you a pang of guilt, screw that. Here’s what you need to know about the ‘breastfeeding makes your baby smarter’ study.
Over the past week the headlines have been triumphant: “The longer babies breastfeed, the more they achieve in life – major study” from The Guardian. And “Breastfed babies grow up smarter, richer, study shows,” from The Telegraph.
Around the world, two things happened – breastfeeding advocates shouted “See – we told you so!!!” And non-breastfeeding mothers either wept over their formula tins or furiously typed into comment boxes, “But I can’t! Mastitis and… pumping… PND…. Don’t you dare judge me!”
Now, you might expect a person who wrote a book called, “Guilt-Free Bottle-Feeding: Why your formula-fed baby can be happy, healthy and smart” to be in the latter category. But actually my response was a big, fat:
“Meh.”
It was so meh that I wasn’t going to bother writing about it, but the continued attention it’s received has drawn me out of my meh-ness, to explain why, as the mother of a predominantly formula-fed child I am not at all perturbed by the study and its findings, and why you shouldn’t be either. So here goes:
1) The study doesn’t tell us anything we don’t already know, or didn’t already suspect. Multiple studies into children have suggested a small dose-response boost in IQ from breastfeeding. This study is unique in that it tested adults, but it’s not surprising that it finds adults receive a small boost in IQ from breastfeeding if it’s already generally acknowledged that kids do.
Related content: Some say this picture is beautiful. Others say it’s “sexualising” breastfeeding.
2) The non-breastfed babies in this study received formula that didn’t have added long-chain polyunsaturated fatty acids added to it. The authors themselves theorise that these brain-boosters, which are found in abundance in breastmilk but not in regular formula, could be behind much of the IQ boost. If the babies in the study had been given a modern-day formula with added LCPUFAs in it, it is very possible, even likely, that the boost in IQ points might have been less than 4 points.
4) Four IQ points ain’t that much. In practical terms, it has an almost immeasurable difference on day-to-day capacity on an individual level. Now, the study’s authors posit that the boost they found in the breastfed babies’ incomes in their study was down to the group having a higher IQ. However, as one of the authors, Dr Bernardo Lesso Horta acknowledged in a Lancet podcast this week, breastfed babies tend to come from wealthier homes, “So there is always a question of whether [an outcome like higher IQ] is a consequence of breastfeeding by itself… The kids who are breastfed are wealthier.” So, maybe they have other advantages in life which can help boost their IQ. Either way, I challenge you to tell the difference between someone with an IQ of 112 vs 116.
5) There are so many other things than affect a child’s intelligence over time. The type of parenting a child receives has a far greater effect on intelligence than their early nutrition: the amount of books in a home, the number of words a child hears everyday, encouragement to learn, help with homework, providing a healthy learning environment and a child’s school. And as Dr Amy Tuteur, ‘The Skeptical OB’ pointed out, the same study actually showed that maternal education, family income and birth weight have a bigger effect on IQ than breastfeeding.
Want more? Try: 18 things we wish we’d known about breastfeeding (before we started).
6) There are many families where, taken holistically, breastfeeding is the less good option. For example, if a mother’s post-natal depression is exacerbated by breastfeeding, if breastfeeding hurts due to repeated mastitis, or babies can’t latch, or mothers have to go back to work and can’t or don’t want to manage the burden of pumping. Or, God forbid, a mother just doesn’t like breastfeeding. A mother that is happy and healthy is more likely to produce a happy, well-rounded child, and that has effects throughout a child’s life, including in academic and career success. This likely has far more impact than the purported benefits of breastmilk.
7) Forty percent of the original study participants dropped out. As The Atlantic pointed out, this could significantly affect the outcomes of the study, because it is those on the lower end of the socio-economic spectrum who are less likely to be pinned down and return for follow-up testing. This may have skewed the results towards those on the upper end of the social spectrum, who are more likely to be wealthy and then produce more wealthy kids.
To be clear, the study is well-designed, has been well-conducted and its authors are to be applauded for this. But it is not without flaws and caveats.
So, formula-feeding mothers of the world, put away those tears and keyboard clicks of rage. This study changes nothing for you, and your children, for whom you are doing the best for every single day.
This article originally appeared on Guilt Free Bottle Feeding, and has been republished here with full permission.
Madeleine Morris is an award-winning journalist and author of Guilt-Free Bottle-Feeding: why your formula-fed baby can by happy, healthy and smart. She is a reporter for the ABC’s flagship 7.30 program, and blogs at guiltfreebottlefeeding.com. She’s a mum of one, and is frequently in need of a good lie down.
Top Comments
What a load of BS. I was bottle fed as my mother had rhumatoid arthritus and had to go back on her medication after I was born, my brother was breast fed. We are equally "smart" (though he trumps me at maths, but I have a creative brain). I am studying psychology (at 30, I went through my 20s climbing the corporate ladder) and getting credits - its not easy.
Smart or stupid is relative. I know pleanty of "smart" people that are the dumbest people on the planet - its called book smart. And if you actually know about IQ testing, its one of the least favourable testing methods as it does not cover all forms of intelligance.
I am now pregnant and I am not stressed about these silly studies, which by the way are studies - lets look into the bias (who sponsored them? boob natzis or formula companies) what is the study make up etc. if you are a stressed mother you will likely have a child with behavourial problems - lets look into that and smarts.
The study is not without its flaws (very few population studies are perfect) but I take issue with some of your assertions.
“4 IQ points ain’t that much”
4 IQ points is equivalent to 0.26 of a standard deviation, which would be considered pretty strong in most other observational and intervention studies. If a person moves from 100 up to 104 they move from the 50th percentile to the 60th percentile of IQ leapfrogging 10% of the population.
“It is those on the lower end of the socio-economic spectrum who are less likely to be pinned down and return for follow-up testing. This may have skewed the results towards those on the upper end of the social spectrum”
It may have but it didn't. They detail follow-up completion by family income tertiles in the paper. The intermediate group had a higher level of follow-up (68%) but the high and low income groups both had similar levels of follow-up (63%).
“So, maybe they have other advantages in life which can help boost their IQ.“
Certainly, the authors accounted for the following factors in their analysis:
Monthly family income
Maternal education
Parental education
Household assets index
Maternal smoking during pregnancy
Maternal age
Maternal pre-pregnancy body-mass index
Type of delivery
Gestational age
Birthweight
Genomic ancestry