London: Babies who are breastfed grow up to be more intelligent, suggests a new study.
The most comprehensive British study of breastfeeding to date has shown that it continues to have an effect on a child`s mental ability right through secondary school.
The study of more than 10,000 children from the Bristol area found that those breastfed exclusively for at least the first week of life consistently outperformed those put on the bottle from birth.
Researchers at Oxford University and the Institute for Social and Economic Research (ISER) in Essex made their conclusions after "pairing up" children who in all major respects, such as family circumstances and maternal IQ, were identical, reports the Telegraph.
The only difference was whether or not they were breastfed. They then compared each of these "twin" pairs to gauge the difference made by breastfeeding.
Maria Iacovou, a research fellow at the ISER, said breastfed babies had IQs that were on average between three and five points higher.
"We wouldn`t have been surprised if the effect faded with time, but it didn`t," she said.
She added that other studies showed there was an effect in the pre-school years. They excluded such information from this study, as in the Avon study pre-school ability was assessed by the mothers, who she thought were "probably a little biased".
She said there were two schools of thought on how breastfeeding had an effect: that long-chain fatty acids in breast milk helped the brain develop; and that the act of breastfeeding improved the mother-child bond.