Babies who are exclusively breastfed for at least three months have different markers in their blood than babies who were not breastfed.
The findings come from the largest study of its kind conducted across an international consortium. The researchers examined the children’s blood sample data and looked for epigenetic marks across the genome. Epigenetics refers to chemical changes to DNA that affect which genes are active and how they function. Specifically, the research team looked at the epigenetic process of DNA methylation, a chemical process that can be detected in blood samples.
The research was led by the Barcelona Institute for Global Health (ISGlobal), the University of Exeter and the University of Bristol. Clinical epigenetics. The study found that DNA methylation marks in genes associated with immunity and developmental processes were on average higher in children who were exclusively breastfed for at least three months compared to those who were not breastfed.
However, this study did not consider whether there were any differences in children’s immunity or development as a result of having these epigenetic marks.
Our findings show that exclusively breastfed babies have epigenetic changes associated with that experience. Although the genes affected by these markers are involved in developmental and immune processes, it cannot be said from our study whether this has a direct impact on these highly complex processes. ”
AS Dr Doretta Karamaski, University of Exeter
Studies have independently shown that breastfeeding has both short- and long-term beneficial effects on children’s health.
Dr Mariona Bustamante from ISGlobal, an institution supported by La Caixa Foundation, added: “Our results are new and interesting, but must be interpreted with some caution. Our research is designed to be collaborative and international, but to fully understand this biology we need to study more diverse groups.”
The study was conducted through the Pregnancy and Childhood Epigenetics (PACE) Consortium. The consortium consists of 11 international studies involving mixed-ethnic cohorts in countries including Spain, the Netherlands, Finland, France, Greece, Lithuania, Germany, South Africa, and the United States. In the UK, the studies included the Bristol-based 90’s Children Study, the Bradford Born Study and the Isle of Wight Birth Cohort Study. The analysis incorporated epigenetic data from 3,421 children across these studies.
Researchers looked at whether and how long babies were breastfed, and whether and how long they were exclusively breastfed. Information regarding breastfeeding was collected through a questionnaire from birth. DNA methylation marks were measured from samples taken when the children were between 5 and 12 years old and compared to DNA methylation marks from samples taken from the umbilical cord to assess pre-lactation. The researchers investigated whether there were any differences related to breastfeeding experience.
This research clinical epigenetics It is funded by multiple sources including the Medical Research Council, Wellcome and Horizon 2020.
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Reference magazines:
Kalamaski, D. others. (2026). Association between breastfeeding and DNA methylation in the Pregnancy and Childhood Epigenetics (PACE) consortium. clinical epigenetics. DOI: 10.1186/s13148-025-02042-4. https://link.springer.com/article/10.1186/s13148-025-02042-4.
