Genes, IQ, and Breastfeeding

November 6th, 2007

I just couldn’t resist an article on genetics and breastfeeding. It’s a commonly held belief that breastfed babies tend to score higher on intelligence tests , though explanation behind this correlation is lacking. Yesterday, some scientists published a study showing that this correlation was only shown in babies with a certain variant of the FADS2 gene, a gene involved in fat metabolism. Babies without the gene variant showed no correlation between higher intelligence and breastfeeding. Luckily, in their population, the variant that benefited was found in ~90% of the population, so most people would benefit. From the nytimes cover:

“This is not specifically a breast-feeding gene but a gene that influences how we process nutrients,” said Avshalom Caspi of King’s College London and Duke, who led the study. Researchers from Yale and the University of Otago in New Zealand were also involved. The scientists analyzed genetic samples from 3,200 children in New Zealand and England whom they had been tracking since infancy. They focused on a gene involved in the metabolism of long-chain polyunsaturated fatty acids, which are abundant in breast milk but not in cow’s milk or most formulas. One variation of the gene, found in some 90 percent of people, helps the body metabolize the fatty acids more efficiently than the other variation does — and accounted for all the advantage associated with breast milk. The relationship held regardless of family income or parents’ I.Q. “The big message from this,” Dr. Caspi said, “is that it’s not nature versus nurture that’s most important, but how nature works through nurture.”

I won’t go on about the bias inherent to IQ tests, but it’s an interesting finding about a gene-environment interaction. The nytimes article is here and a link to the original research article published in the Proceedings of the National Academy of Science journal. See, this is why I need to get moving on my own personal and science blogs. Please return to your regularly scheduled all-Avery, all the time, programming. :)