This is an excerpt from the manuscript I am currenting working on, for
submission to the peer-reviewed journal Social Science and Medicine, titled
"Evolutionary Medicine and Breastfeeding".  It includes references to all
the studies showing benefits beyond six months.  This includes health
benefits, as well as IQ increases (most for longest breastfed).  Turn it
around and ask the doctor for references showing that it *doesn't* provide
any benefit!  This can be copied and distributed as long as you (1) spell my
name right, and (2) include my title and affiliation (Associate Professor,
Texas A&M University).


"At the same time, however, it is clear from the medical research that the
longer a child is breastfed, the better the health outcome for that child,
even under the best of First World conditions.  Only a handful of studies
have defined breast milk intake as a dose-response variable (Fredrickson,
1995), and looked at the effect of varying durations of breastfeeding on
child health.  Most studies define infant feeding as either breast or
bottle, with the breastfeeding group getting breast milk for varying lengths
of time.  Some have used six-month interval categories, and examined health
outcomes for children "not breastfed," "breastfed for 0-6 months,"
"breastfed for 6-12 months," breastfed for 12-18 months," and "breastfed for
18-24 months or longer."  In every case, regardless of the outcome health
variable, the longer the child was breastfed, the better the health outcome,
with the children breastfed for 18-24+ months having the lowest risk for the
adverse health outcome.  These results hold true for studies on malocclusion
(Labbok and Hendershot, 1987), gastrointestinal disease (Howie, Forsyth,
Ogston, Clark, and Florey, 1990), Sudden Infant Death Syndrome (Fredrickson,
Sorenson, Biddle, and Kotelchuk, 1993; Mitchell, Scragg, Stewart, Becroft,
Taylor, Ford, Hassall, Barry, Allen, and Roberts, 1991), otitis media
(Duncan, Ey, Golberg, Wright, Martinez, and Taussig, 1993), childhood cancer
(Davis, Savitz, and Graubard, 1988; Golding, Paterson and Kinlen, 1990) and
juvenile diabetes (Cavallo, Fava, Monetini, Barone, and Pozzilli, 1996;
Dahl-Jorgensen, Joner and Hanssen, 1991; Mayer, Hamman, Gay, Lezotte, Savitz
and Klingensmith, 1988; Virtanen, Rasanen, Aro, Lindstrom, Sippola,
Lounamaa, Toivanen, Tuomilehto, and Akerblom, 1991).  Likewise, the research
on the relationship between cognitive achievement (IQ scores, grades in
school) showed the greatest gains for those children breastfed the longest;
or, to put it another way, the research showed that the shorter the duration
of breastfeeding, the greater the cognitive deficits (Rogan and Gladen,
1993; Wiessinger, 1996).

Recent research also suggests that many health problems of adults can be
traced to lack of breastfeeding or short duration of breastfeeding,
suggesting that while children raised on formula may survive, they do not
necessarily thrive as adults.  Premature weaning has been found to be a
factor in all of the following diseases or conditions: inflammatory bowel
disease (Acheson and Truelove, 1961), Crohn's disease (Koletzko, Sherman,
Corey, Griffiths and Smith, 1989), celiac disease (Greco, Auricchio, Mayer
and Grimaldi, 1988), Schönlein-Henoch purpura (Pisacane, Buffolano, Grillo
and Gaudiosi, 1992), breast cancer (Freudenheim, Marshall, Graham, Laughlin,
Vena, Bandera, Muti, Swanson and Nemoto, 1994), multiple sclerosis
(Pisacane, Impagliazzo, Russo, Valiani, Mandarini, Florio and Vivo, 1994),
allergies (many studies, reviewed in Cunningham, 1995), chronic respiratory
diseases (also reviewed in Cunningham, 1995), coronary artery disease (Fall,
Barker, Osmond, Winter, Clark and Hales, 1992; Kato, Inoue, Kawasaki,
Fujiwara, Watanabe and Toshima, 1992; Kawasaki, Kosaki, Okawa, Shigematsu
and Yanagawa, 1974; Marmot, Page, Atkins and Douglas, 1980; Osborn, 1968).

At this point in scientific understanding, there is no research available
that looks at the differentials in health outcomes for children breastfed
longer than two years, compared to those breastfed for shorter periods.  All
of the studies that have examined the relationship between duration of
breastfeeding and health outcomes stop with an upper category of 24+ months.
There are no studies comparing the health differential between children
breastfed for three years compared to those breastfed for four years,
compared to those breastfed for five years, and so on.  So, it is impossible
to state unequivocally that there are significant or substantial health
benefits to breastfeeding beyond two years of age.  At the same time, it is
impossible to state unequivocally that there are not significant or
substantial health benefits to breastfeeding beyond two years of age.  The
additional health benefits, in a First World setting, of breastfeeding
beyond two years may be very slight, or they may be significant and not
become apparent until middle-age or later-- the data are simply not
available at this time.  Thus, health care professionals cannot guarantee
mothers that continued breastfeeding will result in noticeable improvements
in lifelong health or longevity for their children.

What is more significant, and very clear, is that health care professionals
have no basis for claiming that the health benefits of breastfeeding ever
cease or become insignificant.  All of the research indicates better health
outcomes the longer the child breastfeeds, up to the current study limits of
24 months.  If the mother and child want to continue breastfeeding, there is
no reason to suggest that they should not.  In particular, there is no
reason to question the motivations of the mother who desires to give her
child the best possible lifelong health, nor to accuse her of ulterior
motives for continuing to breastfeed well beyond two years.

Undoubtedly, in terms of health outcomes, the first year of breastfeeding is
more important than the fourth year.  The first month is more important than
the 24th month.  The first week is more important than the 52nd week.  "Any
breastfeeding," as a research category, has been shown to result in
significant health improvements compared to formula-fed children.  That
doesn't mean that the health benefits ever cease, nor that the cost/benefit
ratio ever becomes so high as to make continued breastfeeding pointless.
Future research may confirm that breastfeeding for the full length of time
normal for our species, in evolutionary and physiological terms, may indeed
result in children who thrive--in terms of physical health, cognitive
development, and emotional stability-- relative to children who were weaned
prematurely."       
Katherine A. Dettwyler, Ph.D.
Texas A&M University