Genetic Studies
In 2007, A. Caspi et al. published a study “Moderation of breastfeeding effects on the IQ by genetic variation in fatty acid metabolism.” The authors noted that there is currently agreement in the scientific community that both genetic and environmental factors effect specific traits rather than one or another. This fact inspired them to try to find a gene that mediates the well-researched phenomenon that children who are breast-fed have higher IQ. In their study they found that babies with a specific version of the FADS2 gene demonstrated an IQ averaging 7 points higher if breastfed, compared with babies with a less common version of the gene who showed no improvement when breastfed. FADS2 affects the metabolism of polyunsaturated fatty acids found in human breast milk, such as docosahexaenoic acid and arachidonic acid, which are known to be linked to early brain development. The researchers said "Our findings support the idea that the nutritional content of breast milk accounts for the differences seen in human IQ. But it's not a simple all-or-none connection: it depends to some extent on the genetic makeup of each infant" and, "further investigation to replicate and explain this specific gene–environment interaction is warranted."
However, an attempt to replicate this study in 5934 eight-year-old children failed: No relationship of the common C allele to negative effects of formula feeding was apparent, and contra to the original report, the rare GG homozygote children performed worse when formula fed than other children on formula milk. Another study of over 700 families also criticized the Caspi et al. study. The study reported no evidence for either main or moderating effects of the original SNP (rs174575), nor of two additional FADS2 polymorphisms (rs1535 and rs174583), nor any effect of maternal FADS2 status on offspring IQ.
Read more about this topic: Breastfeeder, Benefits For The Infant, Connection To Intelligence
Famous quotes containing the words genetic and/or studies:
“Man is not merely the sum of his masks. Behind the shifting face of personality is a hard nugget of self, a genetic gift.... The self is malleable but elastic, snapping back to its original shape like a rubber band. Mental illness is no myth, as some have claimed. It is a disturbance in our sense of possession of a stable inner self that survives its personae.”
—Camille Paglia (b. 1947)
“Possibly the Creator did not make the world chiefly for the purpose of providing studies for gifted novelists; but if he had done so, we can scarcely imagine that He could have offered anything much better in the way of material ...”
—Elizabeth Stuart Phelps (1844–1911)