Janet’s post on The New York Times breast-feeding article reminded me that I had a related post in the hopper that I had drafted at the old blog back in May. I wrote it following PZ Myers’ beautiful and scholarly repost from classic Pharyngula on the human breast milk and the origin of the word galaxy. As is all too common with me, my comments there were longer than most folks’ blog posts, so I’ll reproduce them here:
While reviewing the literature when my wife was breastfeeding, I was amazed to learn of the other beneficial compounds present in breast milk beyond the nutrients [Prof Myers] listed [t]here. Breast milk contains TGF-beta1 and 2, the latter of which has been associated, but not yet causally, with decreased incidence of atopic dermatitis and other atopic disorders in breast-fed infants. Interestingly, (and I have yet to understand the mechanism) ingestion of probiotic supplements by nursing Moms increased the TGF-beta2 concentration of their breast milk more than two-fold.
Mind you, I would be extremely cautious about nursing Moms taking any kind of supplements beyond multivitamins, but this was done under the auspices of a clinical trial and is simply just like eating a good helping of yogurt. I’m also amazed that the TGF-beta2 would have oral bioavailability to permit systemic absorption and distribution, but all bets are off in the neonate.
Finally, folks at the University of Arizona have even found that the breast milk of Moms with extremely premature infants have elevated levels of EGF and TGF-alpha and these could certainly have enough local bioavailability to prevent the gastrointestinal disorders associated with extreme preterm births. Unfortunately, these babies are off in the [neonatal] ICU away from their lactating mothers. Of course, they wouldn’t survive without intensive care, but there is incredible biological beauty in the attempt by the mother’s body to provide greater concentrations of helpful peptides to their premature offspring.