Moderation of breastfeeding effects on the IQ by genetic variation in fatty acid metabolism:
...Breastfed childrenattain higher IQ scores than children not fed breast milk, presumablybecause of the fatty acids uniquely available in breast milk.Here we show that the association between breastfeeding andIQ is moderated by a genetic variant in FADS2, a gene involvedin the genetic control of fatty acid pathways. We confirmedthis gene-environment interaction in two birth cohorts,and we ruled out alternative explanations of the finding involvinggene-exposure correlation, intrauterine growth, socialclass, and maternal cognitive ability, as well as maternal genotypeeffects on breastfeeding and breast milk. The finding showsthat environmental exposures can be used to uncover novel candidategenes in complex phenotypes. It also shows that genes may workvia the environment to shape the IQ, helping to close the natureversus nurture debate.
This reminds me a lot of the findings from a study of polymorphism on MAOA. One allele exhibited sensitivity toward environmental variation, while the other did not. This is a pretty simple norm of reaction, genotypes differently influenced by the same background environmental condition. Ars Technica has more detail. Check out the population differences of the two SNPs they looked at on FADS2.
Via Aziz.
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Yet another example of how mother nature keeps showing us up. Here we where thinking that formula was a decent substitute. However, with this research, doesn't that suggest that we could just add more fatty acids to formula and get the same effect? Still, I totally believe in doing our best to encourage high IQ... without exposing the kids to crazy expectations based off of that. Breast feeding sounds like a simple and easy way to make kids more intelligent.
Also, studies have shown that breasted children are less likely to develop childhood and adult obesity. It would be unfortunate for the formula industry if every case of obesity was caused by the use of formula. I would imagine that it can change the metabolism at a young age. Still, no idea why though.
When I first learned about reaction norms as a first-year grad student, it was an incredible eye-opener. Thanks for providing the links for your readers.