Exclusive breastfeeding linked to lasting DNA changes in children, study finds

Exclusive breastfeeding for at least three months is associated with subtle, long-term DNA changes in children, according to a large international study

Exclusive breastfeeding in early infancy may leave a lasting biological imprint, scientists say. Researchers analysing thousands of children found small differences in DNA patterns years later among those who had been exclusively breastfed for at least three months.

The study adds to growing evidence that early nutrition could shape long-term development. However, experts note that the research does not demonstrate how, or even whether, the observed epigenetic changes lead to changes in health, and caution that the full health implications are not yet understood.

The findings were published in Clinical Epigenetics.

Study draws on international data from over 3,000 children

In the largest study of its kind, researchers from the Barcelona Institute for Global Health (ISGlobal), the University of Exeter, and the University of Bristol analysed blood samples from children to examine epigenetic marks across the genome. Epigenetics refers to chemical changes to DNA that influence which genes are active and how they function.

The research was conducted through the Pregnancy and Childhood Epigenetics (PACE) Consortium, which combined 11 international studies from countries including Spain, the Netherlands, Finland, France, Greece, Lithuania, Germany, South Africa, and the US, and included a mixed-ethnicity cohort.

In the UK, it included the Children of the 90s, Born in Bradford, and Isle of Wight studies, which analysed epigenetic data from 3,421 children.

The researchers looked at whether the babies were breastfed, for how long, and whether they were exclusively breastfed. DNA methylation marks were measured in samples collected when the children were aged 5 to 12 years and compared with those in umbilical cord samples to assess pre-breastfeeding levels. Researchers examined whether there was a difference in the experience of being breastfed.

Largest study links exclusive breastfeeding to DNA changes

The study found that DNA methylation marks on genes associated with immunity and developmental processes were, on average, higher in children who had been exclusively breastfed for at least 3 months than in those who had not been breastfed.

The study did not examine whether the children had differences in their immunity or development as a result of carrying these epigenetic marks.

Study co-lead Dr Doretta Caramaschi, of the University of Exeter, said: “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. “

Dr Mariona Bustamante, of ISGlobal, an institution supported by the la Caixa Foundation, added: “Our results are new and interesting, but we do need to interpret them with some caution. Our study is designed to be collaborative and international, however, we need to study more diverse groups to fully understand this biology.”