Lactnetters -- here's the last of my relevant (or perhaps irrelevant) posts
on supplementary feeding and infant growth, originally posted to parent-l.



And I jump into the fray again!  The standard NCHS/WHO growth charts -- the
pink and blue ones that Ross Labs kindly provides to every pediatrician in
the country, are based on the growth of over 10,000 children measured from
the 1940 to the 1970s.  Many of those babies were formula-fed, and some
*were* breastfed for varying lengths of time.  Formulas changed dramatically
over the years from the 1940s, when most were home-made, until the 1970s
(and of course have changed a lot since the 1970s).  In addition, many of
these babies who formed the sample were started on solids at 2-3 weeks of
age.  Another consideration is that many of these children had various
diseases in early childhood that are uncommon now due to the development of
immunizations, while modern babies have many many more ear infections than
babies used to (I don't know why).

A number of studies have been done showing that breastfed babies grow
differently than bottle-fed babies (as described in the earlier post).
However, before we can construct growth charts based on breastfed babies, we
have to define what that means.  For example, the DARLING studies of Kay
Dewey and colleagues at the University of California at Davis are
well-known, in this regard.  But the designers of the study *did not
control* for how the babies were breastfed -- on demand, including at night,
or on 4-hour schedules with sleeping in separate rooms.  Some babies were
fed on demand, but most were on 3 or 4 hour schedules.  The study designers
don't know how many of each, or in-between styles (every two hours, for
example).  The study designers (and I have talked to Kay Dewey about these
issues face-to-face at some length) did not know about and/or did not
believe the research showing that frequency of breastfeeding affects fat
content (the more often you nurse, the higher the fat content of the milk,
so the more the babies should grow if fed often).  And McKenna's research
showing that co-sleeping babies breastfeed more often than solitary sleeping
breastfed babies, and also grow better -- has not been published yet.  So
there are many reasons to suspect that breastfed babies fed on demand,
including at night, will grow just as fast if not faster than bottle-fed
babies.

The more fundamental problem is one of trying to apply growth standards
based on groups of children to one individual child.  At best it is a rough
proxy that might cue you into potential problems.

In terms of what growth standards should breastfed babies be measured
against, should we try to find a large enough population of children who are
breastfed on demand, including at night with co-sleeping, have excellent
sanitary conditions, no diseases/parasites to deal with, and clean
nutritious supplementation?  Where do we find such a population?  Sweden?
They are also genetically among the biggest people in the world.

The real key is to use the growth charts with a little common sense, and
realize their limitations.
Kathy Dettwyler
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Cockroach queen