Gene explains why breast-feeding makes kids smarter

By Michael Kahn

LONDON (Reuters) - A very common gene can help explain why breast-fed babies tend to grow up to be more intelligent than those raised exclusively on bottled milk.

Breast-fed babies who shared the genetic variant outscored bottle-fed peers in intelligence tests, researchers said. The variant to the FADS2 gene, involved in processing fatty acids, is found in about 90 percent of people, they added.

"For 100 years, the intelligence quotient has been at the heart of scientific and public debates about nature versus nurture," Terrie Moffitt of Kings College London and colleagues wrote in their report, published on Monday in the Proceedings of the National Academy of Sciences.

"Evidence that nature and nurture work together drives a nail in the coffin of the nature-versus-nurture debate."

The study looked at 3,200 children in Britain and New Zealand.

Breast-feeding has many advantages for children including reducing infections, respiratory illnesses and diarrhoea, earlier research has shown. A study presented at an American Heart Association meeting on Monday added healthier blood cholesterol levels to that list.

Although scientists have been looking at potential links between breast-feeding 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.