Are the Benefits of Breastfeeding Overstated? I Doubt It.

Have you heard the news? It turns out that nursing your baby is a big waste of effort because formula is just as beneficial as breastmilk. At least that’s the conclusion you could reasonably draw from recent headlines that assert that there are “no long-term benefits of breastfeeding,” and “breast doesn’t beat the bottle.” Bloggers and reporters suggest we “hold the guilt!” because a “new study finds benefits of breastfeeding [are] dramatically overstated.” What has the media in such a froth? That would be sociologist Cynthia Colen’s cleverly designed new study, which looked at 1,773 sibling pairs in which one had been breastfed and the other had not, and found that—when these kids were between the ages of 4 and 14 years old–there were no statistically significant differences in their BMI, obesity rates, hyperactivity, parental attachment levels, behavioral compliance, or several measures of academic achievement.

I admit that as soon as the “formula is as good as breastmilk” headlines started clogging up my inbox and newsfeeds, I felt skeptical, defensive, and even annoyed. Am I attached to the idea that breastfeeding is hugely beneficial, considering that I nursed exclusively for over two years with my first son and am now doing it a second time? Absolutely. Breastfeeding–while snuggly and sweet and a great way to lose pregnancy weight—is also a serious commitment and involves a lot of personal sacrifice, especially if you plan to do it without supplementing with formula, without a breast pump (obviously not an option for moms working out of the home), and for longer than a year. All this nursing—and the lack of traveling, sleeping, and drinking margaritas—had better be ensuring that my sons are healthy little geniuses, dammit!

My husband, a stem cell scientist and assistant professor at Weill Cornell Medical College, got his hands on Colen’s manuscript, and I spent an evening poring over the 57-page document (while breastfeeding my 8-month-old, naturally). There are some really obvious issues that jumped out right away, and I won’t spend  much time addressing the ones that many bloggers have already tackled, such as, what about the many established health benefits enjoyed by a breastfeeding mother, especially if she breastfeeds multiple children for long durations? Or how about the fact that Colen only looked at kids over the age of 4? She does briefly acknowledge the nutritional value of breastmilk for newborns, but the media is ignoring the numerous, well-established health benefits breastfeeding offers infants—such as a proven decrease in SIDS risk.

But let’s forget about the benefits to moms and babies for a minute, and focus on Colen’s conclusions about children ages 4-14. Does breastfeeding really offer NO benefit to this group? In order to answer that, Colen would need to address the following:

1. For how long did these women breastfeed? The mothers who participated in this study were asked two questions: did you breastfeed your baby, and if so, for how long? I read the manuscript over and over, and bugged my husband to help me understand the tables of data, and it’s official: nowhere does Colen mention what the average duration of breastfeeding was for the families studied. In fact, she doesn’t tell us anything about the duration of breastfeeding for any of the families, except to say that the length of time a child was breastfed didn’t affect the outcomes. In Colen’s analysis, an infant who was breastfed even one single time would be put in the breastfed category (and of course this child’s outcomes cannot be expected to be different from a sibling who was never breastfed at all). What if the average breastfeeding duration among the study’s participants was two weeks? And what if no woman breastfed for more than 4 months? In that plausible scenario, the results of this study aren’t very meaningful, or at least need to be interpreted differently. Studies show that very few women in this country exclusively breastfeed for a significant amount of time (less than 15% at 6 months postpartum), so I suspect that the number of babies in this study who were breastfed for more than a few months is quite small (the fact that Colen measured breastfeeding in weeks instead of months supports this theory). In fact, it seems likely that a mother who lacks good support to breastfeed the first time, and therefore doesn’t stick with it, might opt to formula feed her next child right from the start, possibly concluding that she doesn’t produce enough milk. I know several moms in this exact situation, and I would not expect their eldest child to have different math scores at age 14 than the younger siblings, obviously.
2. Were these babies exclusively breastfed? Another huge piece of missing information here is how much these women breastfed—in other words, were the babies also fed formula? I don’t know anyone who exclusively breastfed one child and exclusively formula-fed another. This isn’t to say such situations don’t exist, but my hunch is that most of the babies who were put in the “breastfed” bucket were fed some combination of breastmilk and formula. Other studies clearly demonstrate that exclusive breastfeeding is protective against a number of diseases and that “partial breastfeeding” (supplementing with formula) provides much weaker protection, so knowing whether the breastfed siblings were exclusively breastfed (or even mostly breastfed) is important when looking at long-term outcomes.
3. How did the author choose which outcomes to study? Colen’s selection of long-term outcomes is curious. Other studies on breastfeeding duration have failed to show a substantial effect on obesity, asthma, and intelligence (three outcomes that Colen chose to look at), but have showed a significant effect, for instance, on the risk of high blood pressure and type-2 diabetes (two outcomes Colen chose to ignore). Colen’s previous body of work focuses on socioeconomic and racial disparities in a variety of healthcare issues, and again in this paper she asserts that these factors are responsible for the better outcomes of breastfed babies (rather than the breastfeeding itself). It seems possible that Colen cherry-picked which outcomes to study in order to support her thesis.

Breastfeeding Isn’t a Panacea, But We Should Make It Easier

I will concede that breastmilk isn’t necessarily the liquid gold many of us want to believe it is (every time my son, Wolfie, gets a runny nose, you will find me shaking my fist shouting, “But what about the ANTIBODIES?!!”). It isn’t a cure for all illnesses, and it doesn’t guarantee your kid admission to Harvard or a BMI of 18 for life. But I mean, come on, it’s better than formula. We all know this intuitively, even without the bajillion studies other than Colen’s that strongly suggest the superiority of breastmilk.

What vexes me most about Colen’s study and the sensationalist news headlines that followed isn’t that it lets formula feeders off the hook—I’m all for making parenting choices that work for you and not feeling guilty about them, and I know loads of wonderful formula-feeding moms who have robust, bright, well-adjusted kids. What bugs me is that this one questionable study has shifted the focus from where I believe it needs to be: and that’s on improved policies and support—like paid maternity leave and better postpartum healthcare—that would enable more mothers to have successful and pleasant nursing experiences, should they choose to breastfeed.

(By the way, if you do formula-feed, you should read our Safe Infant Formula Guide.)

Stay sane,

Maia