November 06, 2007
Gene Boosts IQ Benefit Of Breast Feeding

Here is news some new moms can use. Whether breast feeding will boost offspring IQ comes down to which genetic variations the babies carry.

DURHAM, N.C. The known association between breast feeding and slightly higher IQ in children has been shown to relate to a particular gene in the babies, according to a report this week in the Proceedings of the National Academy of Sciences.

In two studies of breast-fed infants involving more than 3,000 children in Britain and New Zealand, breastfeeding was found to raise intelligence an average of nearly 7 IQ points if the children had a particular version of a gene called FADS2.

The distribution of FADS2 genetic variants probably varies around the world. Anyone know of a source of data for FADS2 genetic variant distributions in human races and local ethnic groups? That information would probably indicate whether results would hold up in all human populations.

"There has been some criticism of earlier studies about breastfeeding and IQ that they didn't control for socioeconomic status, or the mother's IQ or other factors, but our findings take an end-run around those arguments by showing the physiological mechanism that accounts for the difference," said Terrie Moffitt, a professor of psychological and brain sciences in Duke University's Institute for Genome Sciences and Policy.

Moffitt, who performed the research with her husband and co-author Avshalom Caspi at King's College in London, found that the baby's intellectual development is influenced by both genes and environment or, more specifically, by the interaction of its genes with its environment.

"The argument about intelligence has been about nature versus nurture for at least a century," Moffitt said. "We're finding that nature and nurture work together."

These results suggest that most women should breast feed. Only 10% of the women in the study groups had babies with genetic profiles which prevented a benefit from breast feeding.

Ninety percent of the children in the two study groups had at least one copy of the "C" version of FADS2, which yielded higher IQ if they were breast-fed. The other 10 percent, with only the "G" versions of the gene, showed no IQ advantage or disadvantage from breastfeeding.

A cheap test for FADS2 variants could help millions of women weigh the costs and benefits of breast feeding. Find out from a genetic test whether newly born junior will turn out smarter if you structure your life so that breast feeding is practical.

The benefit of the "C" version of FADS2 might come from its ability to convert other fatty acids to DHA.

The gene was singled out for the researchers' attention because it produces an enzyme that helps convert dietary fatty acids into the polyunsaturated fatty acids DHA (docosahexaenoic acid) and AA (arachidonic acid) that have been shown to accumulate in the human brain during the first months after birth.

A baby formula high in DHA might deliver the same benefit as breast feeding and deliver that benefit regardless of genetic variations carried by a baby. Mom eating salmon every day and then breast feeding might similarly deliver that benefit regardless of genetic variation.

A 7 point IQ boost is a really big deal. A country that boosted its average IQ by 7 points would experience a huge boost in economic growth and a rise in per capita GDP as the smarter kids made their way into the labor market.

Share |      Randall Parker, 2007 November 06 08:25 PM  Brain Development

Rob said at November 7, 2007 12:43 PM:

Hey Randall, I couldn't find the original paper, but bbartlog in a comment at gnxp says the SNP is rs174575.

The C version gives seven points, and from the hapmap, frequencies follow.

Caucasian C: .717 G: .283 At least on C: .919 (my calc, assumes hardy-Weinberg for all pops)
Chinese C: .889 G: .111 At least on C: .987
Japanese C: .898 G: .102 At least on C: .989
Yoruban C: .725 G: .275 At least on C: .924

So it looks like Africans have a small advantage on whites, and Asians have a bigger advantage over Africans. I don't know the rate of breast feeding in Asia and Africa, but a frequent charge against formula makers is that they discourage Africans from breast feeding.

From Sailer ( 60% of white babies and 30% of blacks are breast-fed.
Since African Americans are mostly African, and the allele frequencies are roughly similar, I'll use Yoruban numbers. a 100% breast-feeding rate will raise the IQ of black Americans by 4.52 points and white Americans by 2.57 points, closing the IQ gap by almost 2 points. Assuming that breast-feeding does not correlate with this allele within populations.

Though I would like to be sure. Children with the C SNP gain 7 points over both people with the G/G genotype and people with C/x genotype who are not breastfed, right?

Marc said at November 7, 2007 2:09 PM:

Hey Rob,

As I pointed out over at GNXP, you just need one version of the C allele to get the 7 points from breastfeeding. So you might want to rework the numbers and see what you get...

Rob said at November 7, 2007 2:38 PM:

Hey Marc,

Sorry I called Mark before. Total accident. The numbers are for C homozygotes and heterozygotes getting 7 points. Our discrepency comes from me upping the breast-feeding rates to 100%, and you upping the black rate to the white rate.

The question at the end was to find out if the breast-feeding raised C people to G people levels(it actually does not) or whether C people who were breastfed got smarter than GG people who are breastfed and Cx people who are NOT breastfed.(They do)

Jolly good show sir!

Half Sigma said at November 16, 2007 9:20 AM:

This breastfeeding-IQ link is more junk science that I debunked.

Breastfeeding does NOT cause higher IQ.

Rob said at September 20, 2008 9:37 AM:

Your debunking got rebunked in the comments.

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