A study published this month illustrates a biological link between a mother’s breastfeeding and other nurturing behaviors on the health of her baby. The study showed that breastfeeding is associated with higher tolerance to stress, as indicated by difference levels in cortisol — a stress response hormone. Additionally, a second biomarker used was DNA samples from buccal cells, or cheek swabs, that showed the degree of suppression of genes related to stress.
The study is the first to replicate animal studies investigating how mother-infant behavior can affect infant health using human participants, said Barry Lester, professor of psychiatry and pediatrics and lead author of the study. Previous studies were only performed on rodents, he added. In consideration of how the findings from animal studies apply to human studies, “if that were true in humans, the implications are staggering,” Lester said.
The study divided mother-infant pairs into two groups: one group of infants that was breastfed and another that was not. Infants that were breastfed saw lower levels of DNA methylation — a process that suppresses genes — of stress-related genes such as NR3C1.
“You can have a methylation test comparable to a blood test that can determine your methylation,” Lester said. “If moms are depressed during pregnancy, the fetus also has increased methylation of NR3C1, and (cortisol is) more reactive at birth.” But there is not yet a biomarker currently available for use in screenings or treatment, he added.
The study demonstrates “the importance of supporting the early caregiving environment and how critical it is for helping children to develop appropriate stress response systems … (and) coping patterns,” said Elisabeth Conradt, assistant professor of developmental psychology at the University of Utah and an author of the study. Conradt also expressed the importance of not shaming those who are unable to breastfeed. "There are many challenges associated with breastfeeding and we shouldn’t assume that all parents are able to do it,” she said.
Both Lester and Conradt agreed on the need for follow-up studies to replicate these results."The sample size was lower than was ideal," Conradt said. “We are planning on performing a replicating study (at the University of Utah), … and we also hope to see some longitudinal studies.”
“In the future, we can … look at other markers and behavioral parameters,”said Todd Levine, clinical associate professor of psychiatry and human behavior, who was unaffiliated with the study. Overall, the study has “strong implications for how we raise children,” Levine added.
The research is “a point of pride” for the hospital, he said.