9 April 1996
Subject: How much milk?

In response to posts by Lisa Marasco, Arly Helm, Patricia Drazin, Joy
Anderson, and Jan Barger (thanks for your kind words, Jan!): you've all
pushed one of my favorite buttons.  Years ago Maureen Minchin told us in the
JHL that average milk production was 750 mls a day at one month and 850 at
four months.  I've been wondering about this ever since.  Here are some of my
speculations:

1)  Growth spurts.  All those breastfeeding counselors can't be wrong. There
must be something that happens at periodic intervals throughout early infancy
which causes mothers to report the pattern of increased nursing frequency for
one-three days that we call "a growth spurt."  Since the studies on milk
production do not indicate that milk supply increases during those periods,
maybe it's the fat content that changes.  Mike Woolridge has reported that
shorter time intervals between feeds raise the fat content of milk.  Once the
baby has got the fat content to where she wants it, she can slack off on her
demand...until the next time.
2)  Growth spurts II.  There are certainly other variables besides milk
quantity and milk quality.  One could be infant gut maturation.  What are all
those epidermal growth factors doing in the baby's gut?  Why do younger
babies poop with every feed and older ones save it up for several days?  Why
do some babies have watery stools or "seedy" (which might better be called
"curdy") stools and other babies have creamy stools?  Surely these different
poop patterns indicate that babies differ or change in their ability to
absorb nutrients.  Absorb more efficiently, and you can gain weight on less
milk per kilo of body weight.
3)  Growth spurts III.  So for awhile I discounted the notion of growth
spurts, or subscribed to the notion that we should call them appetite spurts
instead.  Then I read this article: Lampi M, Veldhuis JD, Johnson ML:
Saltation and stasis: a model of human growth. Science 258:801-803, 30
October 1992.  Here was a lovely piece of research.  They actually measured
babies for several months; some were measured as often as every day.  And
they found that babies poke along not growing (stasis) for awhile and then
they grow in a spurt (saltation).  I can't find my copy just now, so I can't
do what I usually do, which is to look again to be sure I remember it right,
that some babies grew as much as a centimeter in length in 24 hours!  Not
that surprising, I guess, knowing that that's how most other human
development seems to work.  Think of the way your teen's shirt sleeves
suddenly become an inch too short.
4)  Dietary requirements.  Looking at the puzzle from another angle, I have
found an article by R.G. Whitehead quite interesting.  (For how long is
exclusive breast-feeding adequate to satisfy the dietary energy needs of the
average young baby? Pediatric research 37:2, 1995, 239-243.)  This is based
on a lecture given "in connection with the 1994 Nutricia Foundation Award,"
and before you jump all over me, I'll admit that Nutrica is a large
manufacturer of artificial feeding products for babies and, according to
IBFAN, a flagrant violator of the Code.  However, the article may be an
honest reporting of one researcher's dilemma as he came to realize over
several decades of work on infant nutrition that the recommended dietary
allowances (RDAs) for babies were set too high.  He describes what I would
call a wrong-headedly conservative way of proceeding: when it became apparent
that RDAs for babies were too high (thus throwing doubt on the ability of
mothers to meet babies needs by exclusive breastfeeding), the committees who
had to make recommendations were reluctant to lower the RDA to match the
evidence.  They reasoned that it was more "prudent...when in doubt to err on
the side of caution."  I would have suggested that the cautious approach
would be to look at the babies who were thriving on mothers' milk alone for
six months or more. However, since the research he describes took place from
the 1970s to the 1990s, perhaps he had trouble locating such babies.
5)  Dietary requirements II.  Anyway, in the article, Whitehead tells how new
ways of estimating the milk intake of babies have led to a new understanding
of their energy needs.  Contrary to what you might imagine, Arly, the
requirement of calories per kilo per day drops from 115 at birth to about 85
at six months, then rises slowly.  This explains how babies can grow without
increasing their amount of intake.
6)  Comparing to "the other stuff."  It has been my understanding that
artificially fed babies do increase the amount they take as they grow.  (I
don't have a source on this, though.)  I agree with Jan; I think it may be
partly due to the fact that the composition of formula does not change as it
comes out of the bottle, so the only cue the baby has for satiety is getting
full.  Baby gets bigger: the stomach grows: it takes more food to feel full.
7)  A final note.  I am uncomfortable with charts that tell mothers how much
milk their babies need at various ages and weights.  I'm thinking of one on
the blue Medela tear-off, for instance.  Knowing that the average mother
produces 750-850 ml of milk a day, the amounts listed on many charts (based,
I suspect, on bottle/formula fed babies) are intimidating.  How many mothers
feel they don't have enough because they can't pump the amount it says on the
chart?

When you come right down to it, a baby at the breast is the one who knows
best.

Chris Mulford.  [log in to unmask]