Stem cells make up 2% of human milk.
How amazing is it that breastfed babies ingest thousands to millions of viable stem cells with every mouthful of breastmilk. Not just in colostrum, but also in mature milk, and for the entire time the infant or child is breastfed.
This was a relatively new discovery first written about in 2007 by an Australian molecular biologist studying the complex cellular components of human milk. Prior to this embryonic stem cells were known to exist in amniotic fluid and also in the umbilical cord and placenta, however Mark Cregan’s discovery demonstrated for the first time that embryonic stem cells are also present in adults, and become activated in the mammary glands during the hormonal programming of pregnancy and lactation. Whilst research is ongoing further studies appear to suggest that live stem cells in breastmilk travel into the bloodstream via the stomach before passing into the organs, potentially differentiating into specialised cells with the capacity of replicating very specific cell functions.
What does this mean? We are probably all aware of the importance of research into stem cell use in modern medicine and their unique ability to regenerate damaged tissues and treat diseases of the blood. The evidence that stem cells are able to differentiate from non-specialised into very specific cell types is already used in the treatment of blood disorders such as leukaemia and lymphoma, and demonstrates promising results in treating diseases such as diabetes, heart disease, spinal injuries and Parkinson’s disease. The discovery of active embryonic stem cells in human milk infers a none foetal source of stem cells for regenerative medicine, a perhaps less controversial and far more accessible source of this unique and potentially exceptional medical intervention.
So what does this mean for breastfed infants and their health as they become adults? Like many components of breastmilk there is still a way to go before we really understand how stem cells contribute to the optimal health of the individual, however this discovery clearly demonstrates that human milk is not just supporting nutritional needs; that these personalised stem cells may well programme the infant’s development and resistance to diseases beyond the uterus, as the work of the placenta is taken over by the mammary glands and human milk, enabling an internal repair system able to replicate and maintain tissue health over the course of a lifetime.
Author Wendy Birtall
6th April 2026