Breastfeeding, IQ & Success: A few thoughts on the newest study to cause unnecessary worry for parents

“The longer babies breastfeed, the more they achieve in life,” proclaimed an article in The Guardian this morning. And around the world, millions of parents felt their stomachs lurch. Not because of what the study this article referenced actually said, but because they know, from experience, what this study means.

It means that we will continue to be beat over the head with “breast is best” proclamations that have fudge-all to do with our individual realities.

It means that we have to avoid social media for the next few days, unless we want to silently endure smug status updates, or be labeled “defensive formula feeders” if we dare offer an alternative point of view.

It means that those of us who are newly minted moms and dads, still anxiously watching our babies’ chests rise and fall and worrying about the color of their feces and every ounce they gain, will wonder if they should have tried harder/could have done something differently/might have chosen another path.

It means we will witness another media cycle where reporters regurgitate the same mommy-war bullshit, throwing in condescending caveats about how it’s “still a mother’s choice” whether or not she nurses her child.48fc15010a26b03f8586826f99699143

It means that society is still, as always, missing the damn point.

As for the study itself…. what it means is a lot less obvious. Here is the summary:

Methods

A prospective, population-based birth cohort study of neonates was launched in 1982 in Pelotas, Brazil. Information about breastfeeding was recorded in early childhood. At 30 years of age, we studied the IQ (Wechsler Adult Intelligence Scale, 3rd version), educational attainment, and income of the participants. For the analyses, we used multiple linear regression with adjustment for ten confounding variables and the G-formula.

Findings

From June 4, 2012, to Feb 28, 2013, of the 5914 neonates enrolled, information about IQ and breastfeeding duration was available for 3493 participants. In the crude and adjusted analyses, the durations of total breastfeeding and predominant breastfeeding (breastfeeding as the main form of nutrition with some other foods) were positively associated with IQ, educational attainment, and income. We identified dose-response associations with breastfeeding duration for IQ and educational attainment. In the confounder-adjusted analysis, participants who were breastfed for 12 months or more had higher IQ scores (difference of 3·76 points, 95% CI 2·20–5·33), more years of education (0·91 years, 0·42–1·40), and higher monthly incomes (341·0 Brazilian reals, 93·8–588·3) than did those who were breastfed for less than 1 month. The results of our mediation analysis suggested that IQ was responsible for 72% of the effect on income.

Interpretation

Breastfeeding is associated with improved performance in intelligence tests 30 years later, and might have an important effect in real life, by increasing educational attainment and income in adulthood.

 

In laymen’s terms, these researchers interviewed a large group (3493) of 30-year-olds who were part of a larger study which began in 1983, when these folks were born. They chose these subjects based on the fact that they had a significant amount of data on their infant feeding patterns and follow-up data, and because they agreed to be interviewed for the project. They gave them IQ tests, and found that those who had been at least “primarily” breastfed for 12 months scored about 3 points higher, on average. (This doesn’t mean that every single formula-fed subject scored lower, or that every single breastfed subject scored higher – we are talking about aggregates here, not individuals.) The breastfed subjects also tended to have a little under a year more schooling and make a bit more money per year.

The researchers (and the media) claim that this is the first study to so clearly show a causal (and dose-related) relationship between nursing and intelligence/success in later life.

The critics claim that because they did not control for maternal (or paternal, for that matter) intelligence, the results are not so convincing. I agree that parental IQ is far more important than most of what they did control for, but they did at least control for a fair number of confounding factors, like socio-economic status, parental education level, income, birth weight, and so forth. They also had the advantage of using a cohort for which breastfeeding wasn’t associated with class; in other words, people across all socioeconomic groups breastfed and didn’t breastfeed, ruling out the concern that some of these positive effects would merely be associative (rich people breastfeed, rich people have better opportunities/resources, etc.).

There could very well be a correlation between those in this study who were breastfed and better outcomes in terms of IQ and success. I do have some questions, though:

1. What were the formulas like in Brazil, circa 1982?

I couldn’t find anything regarding the types of foods used as breastmilk substitutes in Brazil in 1980-1983. At best, they were the same or similar to American brands, which were somewhat different than how they are now. Not vastly so, but enough that it could potentially make a difference. (Then again, most of us were raised on these formulas and don’t seem too damaged because of it, so…. make of it what you will.) The study did not specify what these babies were eating in place of the breastmilk: properly prepared, commercial infant formula? Homemade formulas? Animal milk? This does matter. We need this info before we can begin to make assumptions about the risks of formula, because for all we know we may not even be talking about formula.

2. What, exactly, were the politics of breastfeeding in Brazil, circa 1982?

The authors talk about breastfeeding not being associated with SES in this cohort, but what did cause women to choose formula over breastfeeding, and vice versa?

According to a 2013 paper in Revista de Saude Publica, “Campaigns promoting breastfeeding began in Brazil in 1981 with the National BF Promotion Program. The 1980s was marked by significant advances in legal protection for BF, with the approval of the Brazilian Code of Marketing of Breast Milk Substitutes and the inclusion of the right to 120 days maternity leave in the Constitution.” I also found references to a Brazilian television campaign which promoted breastfeeding, initiated in the early 1980s which featured spots aimed at various demographics, using language, images and celebrities that would appeal to these specific groups. This implies that the author’s assertion that their study was able to negate possible confounding factors might be overstating it a bit. Socioeconomic status is not the only thing that could give a child a slight bump in advantages associated with success later in life. If there were fundamental differences in the mothers who chose to breastfeed back in 1983 Brazil, those differences would matter for the purposes of this study.

3. Why is a 3-point bump in IQ and a slightly higher income so important for public health, anyway?

The authors state that these findings are important on a public health and economic level. But let’s get Orwellian here, for just a second: if everyone is breastfeeding, then everyone is getting the 3-IQ point and 1-more-school-year advantage. Everyone is making more money per year.  The playing field is even. I nearly failed Econ, so correct me if I’m wrong, but don’t you need “have-nots” to have “have’s”? If the whole country is smarter, then I guess you’d have an economic advantage… but the breastfeeding research world is quite international in scope. After all, our recommendations come from the World Health Organization, not the Every-Country-For-Herself Organization. If we all are smarter from breastfeeding, that’s great – but it’s not much of an economic argument, is it?

Obviously, I am being entirely facetious with the a paragraph. I am far from convinced that breastfeeding makes you smarter or more successful. But I want to point out how convoluted these arguments in favor of breastfeeding truly are. How offensive they are. The implication is that our life’s worth is measured in IQ and financial reward. How about a study showing how traits like patience, kindness, acceptance, creativity, ingenuity are tied to infant feeding?

This study was funded by public health agencies, so these questions are important. When we confuse public health messaging with messaging about IQ and “success” (a quite narrow definition of it, incidentally), we are heading down a very slippery slope.

4. Why aren’t we asking why and how, instead of droning on about the same old tired shit?

If – and this is a strong if – the author’s hypothesis that the fatty acids in breastmilk may be the cause of this bump in IQ (which they imply is what provoked the longer time in school and the greater income – again, sort of a sloppy connection, considering there’s many people with incredible IQs and low levels of education and career success), then why is the take-away “see, everyone should breastfeed!” and not “how can we improve breastmilk substitutes so that all babies get this advantage?”

The study itself is only noteworthy because it followed a lot of people over a lot of years. But remember: associative data is always associative data. Sure, larger groups make for more dramatic assumptions, but at its core, this is just like any other infant feeding study: it shows that there is a slight advantage for people who were breastfed. It doesn’t show how, it doesn’t show why, and it doesn’t tell us squat about anything on the individual level. It does not in any way prove that tour brilliant formula-fed child would have been 3 points more brilliant if you’d managed to breastfeed her. And even if it did prove without a doubt that breastfeeding added 3 points to every single baby’s IQ, it would not tell us how many IQ points a baby might lose if she was starving for the first 6 months of her life, or if her mother was crying and absent all the time, hooked up to a pump, instead of interacting with her. Or if the breastmilk she was getting was laced with any number of substances. Or if her mom didn’t eat enough kale. Or too much kale. Or if her mom ate dairy and she had an undiagnosed MSPI. Or if her dad was an asshole. Or if she was abused and dropped out of school and did drugs that dulled her senses, rendering her unable to even take the bloody IQ test.

My point is, no matter what this study tells us (and it doesn’t tell us anything we hadn’t already heard), the more important thing is what it doesn’t tell us. Life is about so much more than what you eat in the first few months of your life. That doesn’t mean it doesn’t matter – otherwise I wouldn’t be so crazy about making sure research is done to improve formulas and make sure they are as safe and healthy as possible – but provided your child us getting adequate nutrition, there are just so many other things that can help them along or trip them up.

And don’t hate me for saying this, but you are only one of them. Sure, you’re who they are going to be talking about on the therapists’s couch in 30 year’s time, but they aren’t going to be mad at you for not breastfeeding. They are going to be mad that you missed their school play, that you embarrassed them in front of the cool kids in the parking lot of the mall, that you didn’t support their life’s dream to be a potter specializing in tiny, thimble-sized pots.

So do yourself a favor: throw out the newspaper screaming about breastfed babies “growing up to smarter, richer adults”, turn off the Today Show with its smug newscasters, and talk to your child. Because that’s they want. Not your breastmilk. Not 3 IQ points. They want you, and all your imperfections, and all your concerns for their welfare and your anxieties and your dorkiness and your dysfunction. They just want you.

Until they turn 13. But that’s another story.

 


 

 

 

Breastmilk, formula, and intelligence: our kids still have a shot at Harvard!

….Or Yale. Don’t want to spark a battle over alma maters, here.

The newest study on breastfeeding and intelligence comes out of the University of Southampton, where researchers suggested that “breastfed babies are smarter because their mothers are clever, not because of the nutritional benefits of breast milk.”

This isn’t really that newsworthy, considering another British study made the same claim in 2006. But I immediately cringed at the vague, misleading text of the study’s press release:

…The researchers followed 241 children from birth until four years old to investigate the relationship between breastfeeding and the use of docosahexaenoic acid (DHA) fortified formula in infancy, and performance in tests of intelligence…The researchers found that after they had taken account of the influence of mothers’ intelligence and level of education there was no relationship between the estimated total intake of DHA in infancy and a child’s IQ…

I was not at all surprised when folks started Tweeting about their confusion and anger over this study. It seemed like a huge leap to take a study about DHA and use it to suggest that previous beliefs over the IQ-boosting benefits of breastfeeding were null and void – even to me. Really.

But then I started thinking… perhaps these U of Southampton researchers were just responding to previous research, without us laypeople knowing the whole backstory. Kind of like the Spears-Timberlake dance-offs of yore. Some scientist made one phat move (do the kids still say “phat”? God, I am so old), so the Southampton posse had to bust out an even cooler interpretation of the same move… In other words: was DHA the issue all along? If so, then proving that the DHA in breastmilk does not make us smarter would actually be – dare I say it – a pretty significant find.

I turned to Dr. Sears for an explanation on just how the breastfeeding camp believes that mother’s milk can raise intelligence, and found this. He does outline several theories (not sure exactly what research he’s using to back these up, but hey, he’s Dr. Sears, so it probably doesn’t matter), but first and foremost is – you guessed it – the presence of DHA in breastmilk:


Although intellectual differences between breastfed and formula-fed children used to be attributed to the increased holding and interaction associated with breastfeeding and to the fact that mothers who breastfed were better educated and/or more child-centered, new evidence shows that there are nutrients in breastmilk that enhance brain growth…One key ingredient in breastmilk is a brain-boosting fat called DHA (docasahexaenoic acid), an omega-3 fatty acid. DHA is a vital nutrient for growth, development, and maintenance of brain tissue. Autopsy analysis of brain tissue from breastfed and formula-fed infants shows that the brains of breastfed babies have a higher concentration of DHA, and DHA levels are highest in babies who are breastfed the longest. Infant formulas made in the United States do not contain DHA.

(Okay… just taking a moment here to suggest that the good doctor think about updating his website. Infant formulas made in the United States most certainly DO contain DHA. I know this for a fact, because when we were struggling to find a formula our baby could tolerate, we found something online that suggested some kids might be sensitive to the algae source of DHA favored by infant formula manufactures. We had to search and search to find a formula that DIDN’T have the DHA/ARA blend (for the record, Nestle’s Good Start makes a version without it). I’m not sure at what point these became industry standard, but it has been at least more than a year, since my kid is now 14 months; I’ve worked for several websites, none of them with half the money or notoriety of AskDrSears.com, and this kind of inaccurate information would never have been allowed. We updated at least once every fiscal quarter. So get with the program, Bill.)

Knowing that DHA was supposedly the magic ingredient in past examinations of breastmilk and intelligence, the (admittedly confusing) statements of the Southampton research team make a bit more sense. I then found an article from the UK’s Times Online which goes into more detail about this study:

Previous trials have shown that infants fed on formula milk tend to have lower intelligence and the IQ difference has frequently been put down to a deficit of an omega 3 fatty acid, known as DHA, that is normally found in lower concentrations in formula milk….However, scientists at the Univerisity of Southampton, found no evidence of a link between intelligence and breastfeeding once the mother’s social class and IQ were taken into account. 

The researchers analysed data from 241 children and their mothers in the UK, dividing the babies into three groups — breastfed, those fed with formulas fortified with MHA and those fed unfortified formulas.


The breastfed babies performed significantly better than those given unfortified milk. But once the impact of social class and inherited IQ were taken in to account, breastfeeding appeared to have no affect on intelligence. 

Since the babies given fortified milk were fed with a number of brands, with a range of concentrations of MHA, the researchers also looked for a direct correlation between total MHA intake and IQ at the age of four, but again found no link.

“Factors in the home, such as the mother’s intelligence and what mental stimulation children receive, were the most important influences on their IQ,” said Dr Gale.

Anyway. I hope that clarifies some of the confusion over this newest breastfeeding headline;  I’m logging off to get some sleep now. Because studies show that getting a good night’s rest boosts intellectual performance. And I can use all the help I can get – my stupid Blogger account doesn’t have the spell check option, and I am sick to death of finding typos in my late-night rants.

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