Some observational studies have suggested that children who are exclusively breast-fed have higher IQs through adolescence, and even higher incomes at age 30. But a randomised trial, a more rigorous type of study that better controls for socio-economic and family variables, found that breast-feeding in infancy had no discernible effect on cognitive function by the time children reached the age of 16.
Researchers studied 13557 children in Belarus, assigning them as newborns either to a programme that promoted exclusive and prolonged breast-feeding or to usual care.
Mothers and children were followed with six pediatrician visits during the first year of life to assess breast-feeding habits. The study is in PLOS Medicine. Aged 16, the children took tests measuring a variety of skills. There was no difference, except breast-feeders had slightly higher scores in verbal function.
“If you want to breast-feed in hope of increasing cognitive functioning scores, you may find some benefits in the early years,” said the lead author, Seungmi Yang, an assistant professor of epidemiology at McGill University in Montreal. “But the effect is going to be reduced substantially at adolescence. Other factors, such as birth order and parental education, are more influential.” -
The New York Times