The effect was not enormous, but it was there: Researchers found breastfed children were a few months ahead of bottle-fed children

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Adding another dimension to the breastfeeding debate, a new study finds that children who were breastfed scored higher on tests of language and reasoning at age five than bottle-fed infants. But the reason behind this is still unclear -- is it physiological or psychological?

The research team followed almost 12,000 families from the time the children were infants until they were five years old. The team took note of whether the children were born at term (37-42 weeks) or preterm (28-36 weeks), and periodically asked the parents whether they were breast- or bottle-feeding their children. When the kids were five years old, they took tests that measured language skills, reasoning, and spatial abilities.

Overall, the team found that when children who were born at term breastfed for at least four months, they scored higher on cognitive tests. However, when certain variables like maternal education and social class were removed from the equation, the effect shrank. The connection between breastfeeding and cognition at age five was more dramatic for kids who had been born preterm: in these children, even breastfeeding for at least two months had an effect.

The effect was not enormous, but it was there: The researchers calculated that, on average, it was equivalent to breastfed children being a few months ahead of bottle-fed children.

What mechanism might explain the difference? The researchers offer a handful of suggestions, the first few of which are purely physiological. Infants may obtain more essential long-chain polyunsaturated fatty acids in breast milk than in formula, which help with brain development. Alternatively, they may take in more hormones and growth factors that play a role in cognition. Finally, it's been shown that breastfed infants have fewer infections and earlier developmental milestones than bottle-fed children, which could theoretically affect performance on tests of cognitive function. The third option is social: breastfed infants may get a different form of physical contact while breastfeeding, which could affect development.

The results of the study will surely add fuel to the issue, which has been hotly debated in recent years. If you have questions about the breastfeeding vs. bottle-feeding issue, it's a good idea to consult your healthcare provider, who can help you make the best decision for your particular situation.

The study was carried out by researchers at the University of Oxford, University of Essex, and University of York, and was published in the August 10, 2011, online issue of The Journal of Pediatrics.

Image: REUTERS/Enrique Castro-Mendivil.

This article originally appeared on TheDoctorWillSeeYouNow.com.

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