“So for God’s sake, please breast-feed.”

So says Dr. David Mills, from  U.C Davis, summing up the take-home message from his research described in a great article in the New York Times.  Dr. Mills and fellow researchers Bruce German and Carlito Lebrilla, have discovered that the part of breast milk that cannot be digested by babies (and would technically be wasted), is used by a specific commensal bacteria found only in breastfed newborns.

Commensal bacteria are those organisms that live in our gut and protect us from colonization by harmful bacterial pathogens. By now, you all know how important gut flora is.  If not from articles in health magazines, then from the huge marketing onslaught that encourages us to eat food containing probiotics. Especially probiotics. They have even added probiotics  to dog food.

One important group of probiotic bacteria is the genus Bifidobacterium.  These bacteria are found in the healthy human gut, and are being added to all sorts of foods that tout probiotic benefits, such as yogurts (Activia) as well as dietary supplements.

The researchers  at U.C. Davis have found a specific subspecies of this bacteria,  Bifidobacterium longum, in breastfed babies. This subspecies has a unique set of enzymes that can break down complex sugars found in breast milk that the babies cannot use. The bacteria then grow and colonize the intestinal tract of newborns. This protects the newborns intestinal tract from colonization by pathogenic organisms because they then have no place to live.

Also, these sugars provide a secondary defense from pathogens by binding to receptors on some bacteria and viruses and preventing them from attaching to surface receptors found in the intestinal tract.

The complex sugars were long thought to have no biological significance, even though they constitute up to 21 percent of milk. Besides promoting growth of the bifido strain, they also serve as decoys for noxious bacteria that might attack the infant’s intestines.

However, since this strain of bacteria is only found in newborns and not adults, the researchers are not yet sure where this strain of bacteria are coming from.

The other big take-home message from this article is that although we may not understand why, most components of breast milk are probably important (I want to insert a DUH here but will refrain). And breast feeding takes on a bigger and more important role with every discovery about components of breast milk that we have not been able or interested in replicating in commercial baby formula.

“So for God’s sake, please breast-feed.”

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