The story of breastfeeding's benefits just keeps getting longer and longer. Just added to the list is better stress management in babies.

A new study suggests that breastfeeding may actually change babies' genetics to provide for better mental health.

"What we found is that maternal care changes the activity of a gene in their infants that regulates the infant's physiological response to stress, specifically the release of the hormone cortisol," said Dr. Barry Lester, professor of psychiatry and pediatrics at Brown University.

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Researchers measured levels of cortisol and DNA methylation in the saliva of babies who were breastfed for at least 5 months versus those who were not. Higher levels of cortisol and DNA methylation correlate with a more stressful state.

"Breastfeeding was associated with decreased DNA methylation and decreased cortisol reactivity in the infants," Dr. Lester said. "In other words, there was an epigenetic change in the babies who were breastfed, resulting in reduced stress than those who were not breastfed."

What this means is, babies can be genetically programmed to handle stress better just by being breastfed. How zen is that?

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