Does Breast Feeding Make you Smarter?

rhamilton's picture

In an extensive metaanalysis published in the BMJ (333:945-948, 2006) Der et al provide compelling evidence that the answer is “no.” Breast-fed babies are smarter than non-breast-fed babies but these relatively small differences are accounted for by characteristics of the children’s mothers and their homes. It seems that breast feeding mothers are more intelligent than non-breast feeding moms. There are many reasons to advocate breast feeding but impact on intellect isn’t one of them

Comments

croy's picture

Breast feeding and cognitive function

I read Hamilton' s blog which dismisses the effect of breast feeding on the basis of a meta analysis of studies carried out in full term infants from developed countries and published in the BMJ. The conclusions do not apply to LBWs nor to newborns from developîng countries. Furthermore,duration of breast feeding was not taken into account. Claude Roy

ncharpak's picture

Breastfeeding in developing countries

It is known that the best source of nutrition for a healthy term newborn infant is his/her own mother’s milk. There is a wide consensus in the literature about the advantages of breast feeding during at least the first year of life. These include biological (nutritional and immunological) and psychological benefits. In less developed countries, where economic constrains and poor hygienic conditions in food preparation can play a major role, the importance of breast feeding is even greater for preserving the health and well being of infants.
But on the other hand, premature and LBW infants, regardless of whether they are born, in a developed or a developing country, have the same kind of increased nutritional requirements. This paper published in the BMJ is rigourous, well done and the same authors claim in their conclusion that the generalisability of their results must be considered carefully
Anyway there are enough evidences on benefits of breastfeeding in developed and developing countries to promote it and to accept that perhaps the argument that “breatsfeeding make you smarter” is probably not the right one.

Nathalie Charpak
Pediatrician
Director
Kangaroo Foundation
Bogota, Colombia

NaturalParent's picture

What about the Danish study?

A recently published study in the American Journal of Clinical Nutrition, Vol. 88, No. 3, 789-796, September 2008, shows a positive correlation between duration of breastfeeding and early childhood development. Although it only tracks to 18 months, it would appear to disagree with the BMJ meta analysis.

asharma's picture

re: contradictory findings

It is unfortunately in the nature of the scientific method that when the statisticians say p = 0.05, we should expect to see such results in 1 of 20 studies by chance alone. And that's before we make allowances for publication bias (the very human tendency to suppress or ignore negative studies) and differences which are statistically but not biologically significant. The latter may in fact be the key issue here, since the observed differences - if real - are rather trivial in comparison to all the factors that determine intellectual performance.

As has been said in another context, it is the worst of systems -- except for all the others.

Atul Sharma MD, FRCP(C)
Montreal

ncharpak's picture

Breastfeeding and Early Childhood development

The question we posed in the KMC evidence based guide (http:// kangarooo.javeriana.edu.co) was if in the preterm or low birthweight babies, exclusive or predominant use of breastfeeding from their own mother is associated with a better short, medium and long term psychomotor and/or cognitive development as compared to infants predominantly fed using formula milk?
After reading all the papers, the basic answer was that it is unclear whether there is an association between breastfeeding and better neurological, psychomotor development and better academic performance. However, the association between breastfeeding (the mother decides to feed the infant with her own milk) and better neurological, psychological and intellectual development can be ascertained. Overall the documented effects are more significant in preterm infants than in term infants.

Running experimental studies on humans allocating subjects to breastfeeding, donor's milk or formula is ethically inappropriate. Most of the available observational studies show a positive association between breastfeeding and better psychomotor and intellectual development. Attributing these effects to human milk’s nutritive and biological properties is difficult, since breastfeeding in all those studies is associated in not only to breastfeeding (by the same mother) but also to various levels of mother-child interaction (related to the breastfeeding act), more encouraging and devoted mothers (who have voluntarily decided to breastfeed). In fact, various studies and systematic reviews suggest that the positive effects of breastfeeding may be attributed to confounding factors instead of a net effect of breast milk. In any case, the evidence shows it is appropriate to encourage breastfeeding as much as possible since the point of view of the neurological and intellectual development.
I will read carefully this paper of the American Journal of Clinical Nutrition on this Danish study and post my comments
Warm regards

Nathalie Charpak
Pediatrician
Director
Kangaroo Foundation
Bogota, Colombia

rhamilton's picture

Breastfeeding and development

I applaud Nathalie Charpak’s thoughtful, succinct summation of the issues related to breastfeeding and psychomotor/cognitive development. There are compelling reasons to advocate breastfeeding. Whether it is the nature of the mother’s milk or the act of breastfeeding that is a dominant factor influencing a baby’s neurological and intellectual development may never be determined but this uncertainty does not undermine the clear value of breastfeeding, particularly for preterm babies.

Richard Hamilton,
Pediatrician

kinsley's picture

Breast feeding and Development

I read with interest the summary of the study above noted in Hamilton's Blog and the various useful comments by Natalie and Asharma. While the conclusion of the above study in terms of the importance of breastfeeding to the psychomotor and cognitive development of babies are negative. In developing countries where the existence of a baby in the region alone qualifies as a risk factor for incomplete / Unexclusive breastfeeding, promoting the use of breastfeeding in terms developmental benefits to the baby remains a viable option of achieving exclusive breastfeeding as well as improving the nutritional status of babies.

kinsley

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