DNA Changes Seen In Exclusively Breastfed Children, Study Finds

An analysis of blood samples has found that children who were exclusively breastfed for at least the first three months carry epigenetic markers -- chemical changes in the DNA -- compared to those not breastfed. Epigenetics lies at the interface of genes and environment, an interaction between which produces an observable behaviour. Researchers, led by those at the Barcelona Institute for Global Health (ISGlobal) in Spain and the UK's universities of Exeter and Bristol, analysed the epigenetic process of DNA methylation -- which can be detected in blood samples -- in 3,421 children. The team found that DNA methylation marks on genes associated with immunity and developmental processes were higher on average among children who were exclusively breastfed for at least three months, compared to those who were not breastfed.

However, the study, published in the journal Clinical Epigenetics, did not look at whether these epigenetic marks influenced the children's immunity or development as a result.

DNA methylation acts as an 'off switch' and silences a gene from expressing itself. The process has been studied to be important for embryonic development and genomic stability, among other purposes.

"Our findings show that babies who are exclusively breastfed carry epigenetic changes associated with that experience. The genes that are affected by these markers are involved in developmental and immunity processes, but we can't say from our study whether this affects those highly complex processes directly," study co-lead Doretta Caramaschi, of the University of Exeter, said.

The researchers said that while breastfeeding has been shown to have short and long-term beneficial effects on child health, including a greater cognitive development, and an enhanced immune programming, the biological mechanisms that contribute are only partially understood, with epigenetics emerging as a potential contributor.

The analysis looked at data collected via the Pregnancy and Childhood Epigenetics (PACE) Consortium, constituting 11 studies from countries including France, Germany, South Africa and the US. Information on breastfeeding was collected through questionnaires from birth.

DNA methylation marks were measured from samples taken when the children were aged 5 to 12 years, and compared them with samples taken from the umbilical cord to assess pre-breastfeeding. The researchers examined whether there was any difference related to the experience of being breastfed.

"Breastfeeding was associated with differential DNAm (DNA methylation) in childhood blood at a limited number of CpG (cytosine-phosphate-guanine) sites," the authors wrote.

A CpG site is a DNA region where a cytosine nucleotide is followed by a guanine one and is crucial for epigenetic gene regulation through DNA methylation.

"Positive associations at six cytosine-phosphate-guanine (CpG) sites were identified in childhood blood: four with duration of exclusive breastfeeding, and three with duration of exclusive breastfeeding of more than three months compared to never," the team wrote. 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)