Study reveals link between breastfeeding and child IQ

Babies who are breastfed stand a better chance of becoming intelligent children if they also inherit a version of a gene that is involved in the growth of the brain, researchers have found.

Two large studies of breastfed children confirm that mother’s milk does indeed raise IQ in later life – if combined with a gene involved in the metabolism of fatty acids.

Scientists believe the discovery blows a hole in the “nature versus nurture” debate, as it shows that there is a hitherto unconfirmed interaction between our environment and the genes involved in brain development.

Terrie Moffitt and Avshalom Caspi, the husband-and-wife team who carried out the work at King’s College London, found that the IQ advantage for breastfed children was only true if they had inherited the “C” version of a gene known as FADS2, which handles fatty acids in the diet. Breast milk is known to be rich in fatty acids, and these compounds are also thought to be important in certain aspects of brain development, such as the growth |of nerve endings and the production of neurotransmitters – chemical messengers in the brain.

It was already accepted that breastfeeding increases a child’s IQ significantly, but some critics of earlier research pointed out that in the West this may be because higher social classes tend both to breastfeed their children and spend more money on their education than lower social classes. The latest study, published in the journal Proceedings of the National Academy of Sciences, claims to have eliminated these |potentially confounding |social factors.

“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 connection: it depends to some extent on the genetic make-up of each infant,” Professor Moffitt said. “The argument about intelligence has been about nature versus nurture for at least a century. We’re finding that nature and nurture work together.”

About 90 per cent of the population have the “C” version of the FADS2 gene, so most babies could potentially benefit from breastfeeding in terms of a raised IQ.

A study has also shown that breastfed babies have a lower risk of developing heart disease. Scientists told the American Heart Association that breastfeeding is linked with lower weight and higher “good” cholesterol levels in adulthood.