Hello, all!  I received this reply from Dr. Buescher yesterday and he gave
me permission to share it with all of you.  It is very interesting and
helpful. 
Anne Nans, RN, IBCLC, soon to be PNP!


Ms. Nans:
One of our local LC/IBCLC's here in Tidewater expressed her concerns to me
about this article when it came out last year, and I'll tell you the same
thing I told her. The article has it largely correct. The fact is that a
human is not a mouse or a cow (the latter 2 being the animal models most
commonly used in lactation research) and that the immuniglobulins in human
milk are not handled the same way that they are in murine or bovine milk.
Human fetuses start receiving the mother's repertoire of antibodies
transplacentally at about the 28th week of gestation so that at a term
birth, they are little duplicates of the mother's antibody repertoire and
should be protected against anything the mother has had immunological
experience with as long as her antibody persists in the infant (2-3 months).
Mouse pups and calves have no immunoglobulin to speak of when they are born
and must acquire all of it by absorption of milk immunoglobulin.. Some
studies have shown that immunoglobulin can be absorbed from the mother's
milk (based on appearance of a neutralizing activity in an infant's blood
without a known infectious exposure), but  there is no doubt that these are
trace amounts of antibody. The article is largely correct - human infants do
not transport bulk immunoglobulin from the milk to their blood. This is a
confusion caused by research done in mice/cattle as alluded to in the
article being assumed to reflect the situation in humans... but this is NOT
a problem! It's probably a reflection of evolutionary improvement and
refinement of this "Infant Support System" that we as humans have inherited.
I try to make the point that if you think human milk is food, you're missing
the BIG point of the stuff. Almost all of the immunoglobulin in human milk
remains intralumenal in the gut... it performs a STRIKING role in protection
against enteric infections (as noted in the article). When human infants are
born at term, they already have their mother's antibody profile.. and it
can't be screwed up/lost if a feed is missed or interrupted - having to
acquire all circulating antibody via feeding is a liability in an
environment where safety and security are not assured. Unfortunately the guy
writing the article wasn't aware of the oligosaccharide story in human
milk.. this is a totally "intralumenal" story, leaves most people saying
"WOW" when they hear it, and it is a human milk characteristic...
oligosaccharide content and variety are low in bovine and murine milks..no
surprise the story isn't well  disseminated, except by people that work with
HUMANS. 

My LC friend down here was very upset by the article because she thought is
was hugely incorrect and "DIS'ing" human milk and breast feeding... Its not
- in fact, its great for it's saying 

"What should we make of the facts about the immunobiology of lactation?
First, it bears repeating that even if the immunological benefits are often
overstated, there is clear and obvious benefit to breast-feeding in most of
the developing world. Second, though it is harder to demonstrate in a
scientifically satisfying way, there are probably other biological benefits.
And there are surely economic reasons to give babies human milk instead of
formula, which costs between $1,500 and $3,000 a year. In the developing
world, the economic case against formula-feeding might be as potentially
lifesaving as the immunological one: Money stolen from a poor family's
budget for formula will not be available for food, housing, education-or
even soap."

The gist of the article is that most people don't understand how human milk
works.. I'm in that group! But I think its pretty impressive stuff even if I
don't know all the ways Mother Nature has crafted it to be what the newborn
human infant needs.

Steve Buescher, M.D. 

             ***********************************************

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