We had an extended discussion of the 4-6 month "guideline" for adding solids
here on LactNet, and over on parent-l, back in July of 1995.  I am
re-posting some of my writings on this topic then.


The World Health Organization recommendation to begin solid foods in
addition to breast milk at 4 to 6 months for children all over the world is
based on extensive research on energy intake and growth.  The WHO does have
several new publications detailing the most recent research and their
decision to continue their "4 to 6 month" recommendation.

What many studies of growth have shown is that the "average" baby gets
everything he needs from breast milk alone until four to six months.  This
statement comes from studies of large groups of children, who grow, in their
early months, as a group, right about the 50th percentile of the National
Center for Health Statistics Growth Standards.  This is regardless of
whether you are talking about middle-class Americans or poorest-of-the-poor
Third World children.  When additional foods are *not* added to the diet,
then the average growth of the group tends to begin dropping below the 50th
percentile, by 6 months in the middle-class American groups, and by 4 months
in the Third World groups.  The earlier drop-off in growth of the Third
World children is attributed mainly to the diseases and infections and
parasites they must content with, not the poorer quantity or quality of the
mother's milk (malnourished women make plenty of good quality milk).

Hence the World Health Organization guidelines to add solids beginning 4-6
months, to maintain growth.  No baby is "average" however; some need solids
before the 4-6 month window.  In well-nourished populations, even with very
healthy mothers, the group as a whole begins to fall off if not supplemented
after 6 months.  The point is that within these "groups" are individual
baby/mother pairs, and some babies will do fine if not given any solids
until after 6 months, but other babies will not.

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 1940s to the 1970s.  Many
of those babies were formula-fed, and some *were* breastfed for varying
lengths of time, and some were mixed-fed.  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, whether breast or bottle-fed.  Another consideration is that many of
these children had various diseases in early childhood (measles, polio,
whooping cough) 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.  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 cue,
including at night, or on 4-hour schedules with sleeping in separate rooms.
Some babies were fed on cue, 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).  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 cue, 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, and the general guidelines about
when to start solids, with a little common sense, and realize their
limitations.

Guidelines are very difficult to write that "fit every baby," but the World
Health Organization is expected to come up with ONE guideline for all the
world's children.  It would be useful if the guidelines included some
language indicating that parents/health workers should also try to read the
cues the baby is sending.  In other words, giving babies more control over
the addition of solids, as well as over breastfeeding.  So if your 6 month
old is thriving on breast milk alone, healthy, alert, and growing well,
*and* showing no interest in solids, then you should feel comfortable about
not pushing solids.  Offer finger foods, but don't spoon-feed, for example.
If your 4 month old is slowing down in growth, losing percentile ranks, and
follows every bite of your food as it moves from plate to mouth, and tries
to reach out and grab some, then by all means let them eat!  I think it is
inappropriate to be so bound to the clock/calendar that we deny food to
children who want it, OR push it on those who don't.

The current growth standards are to be used as a yardstick, not a goal.  If
your child consistently tracks along the same percentile, whether that be
the 90th or the 10th, then they are probably growing fine for their own
genetic constitution.  It is when children "fall off the track" that one
worries.  So a baby growing for the first 5 months along the 30th percentile
on breast milk alone who slowly drops down to the 25th, then the 20th, then
the 15th at 6, 7, and 8, months, for example, probably *needs* to have
solids added to its diet.  A child consistently growing at the 30th
percentile for the first 10 months of life on breast milk alone is probably
fine, but if they are grabbing food off your plate, and crying when you
won't share with them, I think they should still be allowed to start eating.

Maybe I was "infected," during my 2.5 years of living in Mali, with Bambara
beliefs about letting children set the pace of when they start to eat solid
foods.