Common gene determines if breast is best
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Breastfeeding is best for your child’s brain as long as a variation of a common gene is present in the baby, researchers say.
Breastfed children with a variant of the FADS2 gene, which is involved in processing fatty acids, score up to seven points higher in IQ tests than bottle-fed children.
But for those children without the variant gene, breastfeeding makes no difference to their intelligence levels.
According to the study, published in the latest Proceedings of the National Academy of Sciences, the variant of the FADS2 gene is found in 90% of people.
Lead author Professor Terrie Moffitt, of the Institute of Psychiatry at Kings College London, says the seven-point difference in IQ “corresponds to a moderate effect size that is associated with many important life outcomes”.
And she rules out other factors behind the IQ difference saying the effect of the variant FADS2 gene is the same regardless of differences in birth weight, social class and mother’s IQ.
Her research team also tested the mothers’ DNA and says the FADS2 gene did not somehow alter the quality of breast milk.
Research has shown breastfeeding has many advantages for children including reducing infections, respiratory illnesses and diarrhoea.
Adding to its benefits, a study, released at a American Heart Association meeting this week, says it also contributes to healthier blood cholesterol levels in adulthood.
Although scientists have been looking at potential links between breastfeeding and intelligence for decades, the direct relationship has not always been clear.
The researchers studied the FADS2 gene involved in processing omega 3 fatty acids, found in foods such as salmon, nuts and avocados, and turning them into nutrients for the brain.
Straightforward
The researchers used data from two previous breastfeeding studies in Britain and New Zealand that tracked the intelligence of a total of 3200 children.
“We took cells from the children and then analysed DNA and then we compared how they scored on IQ tests and looked up if they were breastfed as babies,” Moffitt says. “It was very straightforward.”
While the researchers have found at least one gene linking intelligence and breastfeeding, they say they still need to better understand how FADS2 processes nutrients in breast milk.
They also say many other genes are also likely to play a role in intelligence, but add that their study offers a different approach to unravelling the human genome.
“For 100 years, the intelligence quotient has been at the heart of scientific and public debates about nature versus nurture,” Moffitt says.
“Evidence that nature and nurture work together drives a nail in the coffin of the nature-versus-nurture debate.”
Michael Kahn
Reuters
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