Sunday, March 1, 2009

Breastfeeding Raises I.Q. Levels

Dr. Michael Kramer from the Montreal Children's Hospital did this breastfeeding study that I think you will find interesting. I would love to hear your thoughts!

These results, based on the largest randomized trial ever conducted in the area of human lactation,provide strong evidence that prolonged and exclusive breastfeeding improves children’s cognitive development.

Among the most consistently reported benefits of breastfeeding in developed country settings have been higher results on IQ tests and other measures of cognitive development among children and adults who had been breastfed compared with those who were formula-fed. A meta-analysis by Anderson et al1 in 1999 reported consistent IQ differences favoring breastfed over formula-fed infants, with most differences in the 2- to 5-point range.

Most of the studies included in the meta-analysis were observational in design and were carried out in subjects who were born healthy and at term, although a larger difference of 8 points was reported by Lucas et al2 in follow-up of a randomized trial in pre-term infants. Several of these studies demonstrated a clear dose-response relationship, with larger differences associated with longer durations of breastfeeding. With 1 recent notable exception,3 studies published since the meta-analysis have been entirely consistent with these results and conclusions.
Despite the robustness of the reported findings, many observers remain unconvinced about the cognitive benefits of breastfeeding. As mentioned earlier, the evidence is based almost entirely on observational studies. The beneficial effect of breastfeeding is unlikely to be explained by the higher socioeconomic status of breastfeeding mothers because most studies have controlled sta- tistically for socioeconomic differences.

Some of the studies have even controlled for maternal IQ, with most studies reporting an attenuated but persistent and significant effect.
On the other hand, the benefits are likely to be confounded by other, more subtle differences in the mother’s behavior or her interaction with the infant. These differences are extremely difficult to measure and virtually impossible to control for in observational studies. The solution to these methodological problems is a randomized controlled trial, but randomization to breast- feeding vs artificial feeding is infeasible and probably unethical. It is, however, both feasible and ethical to randomize the participants to a breastfeeding promotion intervention. One strategy would be to promote breastfeeding initiation, but most women decide whether to breastfeed early in or even before pregnancy and such a strategy is therefore difficult with regard to both timing and logistics. An alternative and more feasible strategy is to promote breastfeeding exclusivity and duration among those mothers who have already decided to initiate breastfeeding, with analysis by intention to treat.

Studies showing long-term epigenetic behavioral effects of licking and grooming by mother
rats of their pups25 suggest that the physical and/or emotional act of breastfeeding might also lead to permanent physiologic changes that accelerate neurocognitive development. Finally, it is possible that the increased frequency and duration of maternal-infant contact implicit in breastfeeding vs bottle-feeding could increase verbal interaction between mother and infant, which might also have a stimulatory effect on cognitive development. Irrespective of the mechanism, our experimental results confirm the cognitive benefits of prolonged and exclusive breastfeeding reported in observational studies.

Although breastfeeding initiation rates have increased substantially during the last 30 years, much less progress has
been achieved in increasing the exclusivity and duration of breastfeeding. Because protection against infections in developed country settings does not have the life-and-death implications for infant and child health that it does in less-developed settings, cognitive benefits may be among the most important advantages for breastfed infants in industrialized societies. The consistency of our findings based on a randomized trial with those reported in previous observational studies should prove helpful in encouraging further public health efforts to promote, protect, and support breastfeeding.

Correspondence: Michael S. Kramer, MD, The Montreal Children’s Hospital, 2300 Tupper St (Les Tourelles), Montreal, QC H3H 1P3, Canada (

-NewsAnchorMom Jen


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