[The medical literature] shows that breast-feeding is probably, maybe, a little better; but it is far from the stampede of evidence that Sears describes. More like tiny, unsure baby steps: two forward, two back, with much meandering and bumping into walls. A couple of studies will show fewer allergies, and then the next one will turn up no difference. Same with mother-infant bonding, IQ, leukemia, cholesterol, diabetes. Even where consensus is mounting, the meta studies—reviews of existing studies—consistently complain about biases, missing evidence, and other major flaws in study design. “The studies do not demonstrate a universal phenomenon, in which one method is superior to another in all instances.
The author goes on to discuss the fundamental problem inherent in most human studies: that in order to perform the study ethically, you can not randomize participants into breast-feeding and non-breastfeeding groups. And because of that, scientists are always chasing their tails, trying to control for factors which could confound the results (things like age of the mother, income level, number of siblings in the household). It's not surprising then that studies are often conflicting... some studies show that breastfeeding is beneficial in one area or another, other studies show no difference between breastfeeding and formula. The author notes:
The IQ studies run into the central problem of breast-feeding research: it is impossible to separate a mother’s decision to breast-feed—and everything that goes along with it—from the breast-feeding itself...
My decision to breastfeed had little to do with whether or not there was "proof" in the literature. My decision to breastfeed was based on the idea of breastmilk as a whole food, while formula is more of a synthetic food. I think of breastmilk as YEPD and formula as SC. I know my yeast grow a hell of a lot better on the rich, complex mixture of yeast extract and peptone than they do on synthetic amino acids and ammonium sulfate. I find the complexity of breastmilk reassuring... I mean there was a time when we didn't recognize that Iodine was an essential trace element. I really don't expect that we have identified all of the essential components of newborn nutrition that promote optimum growth and development.
That being said, I think that the benefits of breastfeeding are relatively small (when compared to the contributions of things like genetic makeup, family income, parent's education level, etc). And this is why observational studies like the ones the author discusses have such a hard time proving any significant benefit.
The author's main point, which she obscures with her rather bitter and unfriendly tone, is that the small benefits that breastfeeding may (and I would argue likely) provide don't justify the (sometimes militant) pro-breastfeeding culture. And I couldn't agree more. There has to be a balance between providing women with the cultural and practical support that promotes breastfeeding, and one which does not demonize women who, for any number of reasons choose not to breastfeed.
And, somewhat off topic:
Given what we know so far, it seems reasonable to put breast-feeding’s health benefits on the plus side of the ledger and other things—modesty, independence, career, sanity—on the minus side, and then tally them up and make a decision.
I actually found this sentence a little offensive. Just because this author finds breastfeeding miserable doesn't mean that everyone does, and I resent the way she presents breastfeeding as nothing but minuses. Yes, breastfeeding can be challenging, demanding, tiring, but it is also immensely rewarding. I wouldn't trade my time nursing Bean for anything.