Written by: Jyoti Madhusoodanan, Ph.D. | Issue # 133 | 2026
- Breastfeeding has many benefits to children’s health, but little is known about the molecular mechanisms.
- Breastfeeding is linked to some changes in DNA methylation in potentially significant genomic locations.
- The significance of observed epigenetic changes is small and variable, suggesting a need for further studies.
Consuming maternal milk offers children many short and long-term benefits, as it supports cognitive development, immune programming, and the development of the gut microbiome. But the sub-cellular mechanisms that drive the varied health effects are yet to be fully elucidated.
One possibility is the epigenome. Adding chemical tags to DNA can significantly alter the functions of genes, and the “epigenome,” which captures the entirety of these chemical decorations, can play a significant role in driving health outcomes. In a new study, researchers investigated whether breastfeeding was associated with DNA methylation, one form of epigenetic modification, in children’s blood.
Although some previous studies have examined whether methylation mediates breastfeeding’s protective effects, the evidence has been inconsistent. Two studies, for example, identified a connection between breastfeeding and changes in methylation of the leptin gene, which produces a hormone that controls appetite and feeding. But the data were from small cohorts of participants, and correlations were not replicated across different studies.
In the new work, researchers conducted a meta-analysis of data from approximately one dozen birth cohorts, the “largest investigation to date” of the link between breastfeeding and epigenetic changes, they wrote in their study [1]. They included data from more than 3,400 children across fourteen international cohorts from the Pregnancy And Childhood Epigenetics (PACE) Consortium. The analysis revealed several positive associations between DNA methylation at specific sites and duration of exclusive breastfeeding.
The researchers’ data spanned methylation patterns in blood DNA samples from children between ages five and twelve. They also used data from several cohorts that sampled cord blood at birth, which represents the neonatal epigenome prior to any feeding, as a negative control.
The team placed samples into various categories based on the duration and extent of breastfeeding. One group had no history of breastfeeding, and another had some history of consuming maternal milk, whether from a milk bank or via breastfeeding, in combination with formula or other foods. A third category included those who were exclusively breastfed for some period of time. The last group was further ranked based on the duration of exclusive breastfeeding.
In their analysis, the researchers identified six methylated sites in children’s blood DNA that were positively associated with breastfeeding. Some were linked to exclusive breastfeeding, and others were more strongly correlated with a longer duration of exclusive breastfeeding. They did not identify any methylation patterns specifically unique to samples from the “some” breastfeeding group, where children had received some combination of breastmilk and other foods for a span of time. None of the sites they identified were significantly methylated in the cord blood samples collected prior to feeding. Some of the DNA regions identified as likely important are associated with “related to developmental and immune processes,” according to the researchers.
The researchers noted various limitations of their data. Ten of the sampled cohorts were of European ancestry, and three cohorts had fewer than 100 participants. Overall, the significance of DNA methylation differences between the different breastfeeding categories was fairly small, and each month of exclusive breastfeeding did not strengthen the association. The team also found great variability across cohorts. For example, one association they identified for methylation at a specific location in DNA “seems to go in the opposite direction to the one expected for the known protective effects of breastfeeding on inflammation.” As such, it is difficult to know for sure whether specific DNA methylation patterns help mediate the benefits of consuming maternal milk early in life.
While no specific DNA methylation signatures were identified as significant, the data hint at possible associations that future studies could examine more closely. The researchers’ data was wide-ranging and comprehensive and included children between the ages of five and twelve with a very wide range of exposures to maternal milk. By homing in on samples gathered earlier in life and including a narrower range of definitions of breastfeeding, it’s possible that future studies may identify more specific and significant DNA methylation patterns linked to maternal milk consumption.
References
- Caramaschi D, Fernández-Barrés S, Casey E, Cruells A, Czamara D, Sharkawy ME, Elliott HR, Fore R, Gairola R, Gruzieva O, Huels A. Breastfeeding association with DNA methylation in the pregnancy and childhood epigenetics (PACE) consortium. Clin epigenetics. 2026 Feb 28; 18(1):63