summary: breastfeeding and language development

[leah gedalyovich]

Dear All,
Here is my original question on breastfeeding and language
development. Apologies for the delay in posting the summary.

This question came up from a discussion with a friend who is a
lactation consultant. There seems to be a given that breastfeeding is
better than any other alternative for virtually every aspect of
development. Is there any published research on the relationship
between breastfeeding and language development? If any relationship is
found is it attributed to nutritional issues or to other issues
(emotional, sensori-motor, etc)

I received many more responses than I expected. Thank you to all who
took the time to answer – Anat Ninio, Natasha Ringblom, J. Tomblin,
Katherine Demuth, Nina Capone, Carolyn Bick-Gengler, Katie Alcock, Peg
Lahey, Lynne Hewitt, Jim Morgan, and Ruth. My apologies if I have
unintentionally left anyone out. Here is my summary:

Some people consider suggested that any relationship between
breastfeeding and language development would be related to emotional
issues (Katherine Demuth)  with either positive effects, e.g. Natasha
Ringblom's personal experience of her breastfed children acquiring
Swedish and Russian, or likely negative effects or possible negative
effects from pressure on mothers to breastfeed (anat ninio with a
reference to an article in the Israeli paper Haaretz about the
non-effects of breastfeeding on practically anything, starting with
infant health and continuing with intelligence.  The URL is below.


http://www.haaretz.co.il/hasite/pages/ShArt.jhtml?itemNo=507898&contrassID=2&subContrassID=2&sbSubContrassID=0


There were some suggestions of  positive oral motor development
connected with breastfeeding in typically and non-typically developing
breastfed children:

Carolyn Buck-Gengler's account of her extra motivation for
breastfeeding her (still pre-verbal) two year old son born with Down's
Syndrome, likely improved oral motor strength suggested by
occupational and physiotherapists.

Actual research papers deal with breastfeeding as a protective factor:
Breastfeeding is seen as protecting against the developmental langauge
impairments ... breastfeeding was a protective factor and the longer
the breastfeeding the better the effect. The reference being
D.L. Drane, D. L. &  Logemann, J.  (2000). A critical evaluation of
the evidence on the association between type of infant feeding and
cognitive development.  Paediatric & Perinatal Epidemiology, 14  349
And an earlier reference on prenatal and infancy risk factors for SLI
at 6 years of age that included retrospective information on
breastfeeding.  When mother's education was controlled breastfeeding
was a significant protective factor for language outcome (odds ratio=
0.5).  We also found that there was a dose effect in that longer
periods of breastfeeding had a stronger effect than shorter periods.
Tomblin, J. B., Smith, E., & Zhang, X. (1997). Epidemiology of
specific language impairment: Prenatal and perinatal risk factors.
Journal of Communication Disorders, 30, 325-344.
Specifically the positive effects of nutrition ( long-chain fatty
acids) have been investigated:
Willatts, P., Forsyth, J. S. DiModugno, M. K., Varma, S., & Colvin,
M.(1998). Effect of long chain polyunsaturated fatty acids in infant
formula on problem solving at 10 months of age. Lancet, 35 (9129),
688-691.
But these positive effects may not be specific to language development
and in fact may show only in non-language areas.
When there is control for any "bonding" or SES effects of
breastfeeding -  an effect on some types of cognitive behaviour is
shown in preverbal infants (e.g. problem solving in the above study).
However other studies with similar designs have shown no effect on
language of supplemented formula. e.g.
Auestad, N., Scott, D. T., Janowsky, J. S., Jacobsen, C., Carroll, R.
E., Montalto, M. B., et al. (2003). Visual, cognitive, and language
assessments at 39 months: A follow-up study of children fed formulas
containing long-chain olyunsaturated fatty acids to 1 year of age.
Pediatrics, 112(3), E177-E183.
Birch, E. E., Garfield, S., Hoffman, D. R., Uauy, R., & Birch, D. G.
(2000). A randomized controlled trial of early dietary supply of long
chain polyunsaturated fatty acids and mental development in term
infants. Developmental Medicine and Child Neurology, 42(3), 174 181.
(with thanx to Katie Alcock)
In full term infants exclusively breastfed for at least 3 mos, their
ability to discriminate nonnative phonetic contrasts at 9 months was
related to their levels of DHA fatty acids at 2mos:
Innis, S. M., Gilley, J., & Werker, J. (2001). Are human milk
long-chain polyunsaturated fatty acids related to visual and neural
development in breast-fed term infants? Pediatrics, 139(4), 532-538. '

A previous paper identified a relation between fatty acids and vocabulary size.
Scott, D. T., Janowsky, J. S., Carroll, R. E., Taylor, J. A., Auestad,
N., MOntalto, M. B. (1998). Formula supplementation with long-chain
polyunsaturated fatty acids: Are there developmental benefits? 
Pediatrics, 102, E59-64.

(with thanx to Ruth)
And thanx to Peg Lahey for this link:
For a review of some literature prior to 2004 that includes this topic see
the Bamford-Lahey Children's Foundation website www.bamford-lahey.org.
The focus of the review is essential fatty acids but it includes some
discussion of breastfeeding and development.  It was completed in 2002
and updated in 2003.

For direct access, click on first link below and then click section on
infant development; for update click on 2nd link.  There is some
support re vocabulary and verbal IQ and some suggestion that there may
be a nutritional component related to the higher amount of omega3
fatty acids found in breast milk vs. formula as it was constituted at
the time [some changes recently].

http://bamford-lahey.org/lipidsrev102.html#LIPIDS   for original paper
http://www.bamford-lahey.org/update.html  for a short update in 2003.

Still other research suggests positive effects of breastfeeding as
secondary to improved health:

A substantial number of articles in the pediatric literature report that
reduced incidence of otitis media is associated with breastfeeding. This is
probably due to a combination of factors including antibodies passed to the
child through breast milk and the increased mechanical load in
breastfeeding relative to bottle feeding, which promotes drainage of the
Eustachian tubes (infants' Eustacian tubes are narrower and more horizontal
than adults'). There is at least a weak relation between incidence of OME
in infancy and phonological and lexical measures of language development.

-- Jim Morgan

While it is true that the IQ effects of breastfeeding are far from
clear, if any exist, the fact that breastfeeding reduces infant
exposure to waterborn bacterial and viral infections should mean that
breast-fed infants have a health advantage. There is some evidence for
increased oral motor strength from breastfeeding.

        "Early weaning may lead to the interruption of proper oral
motor development provoking alterations to the posture and strength of
the speech organs and harming the functions of chewing, swallowing,
breathing, and articulation of speech sounds. The lack of
physiological sucking on the breast may interfere in the oral motor
development, possibly causing malocclusion, oral respiration and oral
motor disorders."

Neiva et al, J Pediatr (Rio J) 2003;79(1):07-12
Quoted on http://www.promom.org/101/, a non-profit promoting
breastfeeding.  Lists many other reasons why breastfeeding is
superior.

There is also some evidence that pre-term infants have better oxygen
saturation levels and less incidence of apnea during breast than
bottle feeding. (Review available at
http://www.asha.org/NR/rdonlyres/7BBBE03B-A34C-4052-95A3-742B1EAB11B4/0/v3TRnicu.pdf

The below study found an effect of breastfeeding on oral motor/speech
milestones:

Acta Paediatr. 1999 Dec;88(12):1327-32.   Duration of breastfeeding
and developmental milestones during the latter half of infancy.
Vestergaard M, Obel C, Henriksen TB, Sorensen HT, Skajaa E, Ostergaard
J. Department of Obstetrics and Gynaecology, Aarhus University
Hospital, Denmark.

    Several studies have suggested that breastfeeding has a long-term
influence on brain development. However, interpretation of these
findings is complicated by the presence of many potential confounding
factors. Only a few studies have examined infants before 1 y of age,
although very early assessment might reduce the role of environmental
influence. We investigated the association between exclusive
breastfeeding and three developmental milestones related to general
and fine motor skills and early language development at the age of 8
mo. We followed 1656 healthy, singleton, term infants, with a
birthweight of at least 2500 g, born between May 1991 and February
1992 in Aarhus, Denmark. Information was collected at 16 wk gestation,
at delivery and when the infant was 8 mo old. Motor skills were
evaluated by measurement of crawling and pincer grip. Early language
development was defined as the ability to babble in polysyllables. The
proportion of infants who mastered the specific milestones increased
consistently with increasing duration of breastfeeding. The relative
risk for the highest versus the lowest breastfeeding category was 1.3
(95% CI: 1.0-1.6) for crawling, 1.2 (95% CI: 1.1-1.3) for pincer grip
and 1.5 (95% Cl: 1.3-1.8) for polysyllable babbling. Little change was
found after adjustment for confounding. In conclusion, our data
support the hypothesis that breastfeeding benefits neurodevelopment.

    PMID: 10626516 [PubMed - indexed for MEDLINE]

(with thanx to Lynne Hewitt)

And to summarize: the picture is still far from clear, for positive
effects for language development and even for general cognitive and
emotional development, but there is a growing body of controlled
research  which we can expect will clarify the situation and aid our
decision making for ourselves and for advising others. Thanx again,
Leah