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Infant formula vs breastmilk: oops June 24, 2011

Posted by federalist in Healthcare.
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Advertisements for Enfamil powdered milk often include a striking chart showing that its formula produces infants with mental performance just short of that of breastfed babies, and 7 points higher than that of babies fed its previous formula, which wasn’t supplemented with DHA and ARA.

It appears they’re referencing a study published in the March 2000 Developmental Medicine & Child Neurology. The performance metric was the Mental Development Index of the Bayley Scales of Infant Development (BSID) II.

Anyone who has had a baby in this country knows that there is a raging war between breastfeeding fanatics and their opponents who maintain that (1) not every woman has the capacity or luxury to exclusively breastfeed her babies, and that (2) formula is a reasonable alternative to breastfeeding. The former “breast nazis” tend not to tolerate exceptions to the “breast is best” mantra: Failing to exclusively breastfeed is considered tantamount to child abuse because even modern formula fails to confer all of the health benefits of breast milk. Meanwhile, two generations of adults who were often raised exclusively on formula say, “Relax, we turned out alright.”

Without wading into the debate or the data, I had sympathies for both groups: One would presume that human milk is the optimal food for human babies, and it seems unlikely that scientists have identified and mass-produced every nutrient that breasts distill. On the other hand, it’s obvious that the full range of human potential has been realized in people who never tasted breast milk, and while we may not have perfected it there has been plenty of scientific attention to producing a formulaic substitute.

There exist many legitimate circumstantial obstacles to breastfeeding, so individual feeding practices should generally be respected. But this Enfamil study makes a strong argument for the “Breast is Best” camp: After all, up until ten years ago formula lacked two nutrients that contribute to a significant and measurable improvement in infant development. Oops! So what else is our formula missing, and what is the associated price we’re paying in human health and performance? The short answer: We’ll never know.

Formula has three extraordinary hurdles to jump before it can even begin to address this sort of question:

  1. A specific nutrient has to be identified that is lacking in the existing formula but is present in breast milk
  2. A performance test has to be created that can be applied to babies
  3. A double-blind test has to be run that shows a statistically significant difference in performance between babies fed with and without the nutrient

Perhaps the greatest obstacle is the second. For example, what developmental benchmarks are missing from the BSID? Not only is it hard to measure a baby’s performance on anything, but there is also quite a limit to the performance they can even display at such an early stage of development. Our best current tests might still be missing some testable characteristics, but they are certainly missing untestable or latent characteristics that manifest themselves later in life. However, by the time a human is fully developed any “breast vs. formula” effect has been so muddied by other nurturing factors that it can’t be statistically discerned.

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