Source: French to English Tester Published on: 2026-04-21
Source: The Conversation – France in French (3)– By Ivette Caldelas, Senior Researcher, UDIT – University of Design, Innovation and Technology
Recent data suggest that the baby receives, through breast milk, a microbial ecosystem, including certain beneficial bacteria that prove essential for its development, particularly in terms of the immune system. Rather than placing the responsibility solely on mothers, this research should inspire public policies to support them, for the benefit of infants.
We know that thebreast milkis theideal foodfor thenewbornsthanks to the subtle balance of its components: it contains micro and macronutrients, immune and growth factors, as well as hormones essential for the proper development of infants at every stage of their growth.
Also to read:
Colostrum, first breast milk: benefits, ignorance, and beliefs
However, recent studies reveal something much deeper: milk does not merely nourish, it also transmits aliving ecosystemto the baby. It contains bacteria, metabolites, and bioactive compounds that can shape the newborn’s health from its very first days of life. These discoveries could transform our understanding of modern pediatrics.
Milk is not sterile: it is biologically active
Just a little over a decade ago, according to the prevailing idea, breast milk was considered a sterile food; any bacterial presence was considered contamination. However, large-scale sequencing studies conducted on milk samples from various species have shown that milk contains complex microbial communities. Among these are bacteria belonging to the generaBifidobacterium sp.,Lactobacillus sp.andStreptococcus sp., which are closely linked to the healthy colonization of the neonatal intestine.
This bacterial transfer occurs at a critical moment, when the development of the newborn’s immune system largely depends on the immune modulation provided by breast milk.This microbiotaprovided by the mother plays an important role in the maturation of the intestinal barrier, the regulation of inflammation, and the metabolic programming of the newborn.
In other words, breast milk does not only provide calories: it also contributes to the development of the immune system.
A biological dialogue between the intestine and the breast
Recent data highlight a fascinating phenomenon, which scientists have called “entero-mammary pathway.” Thanks to this mechanism, certain bacteria present in the maternal intestine would be able to migrate to the mammary gland, where immune cells would act as carriers.
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Dialogue around the microbiota: how the mother and baby communicate through breast milk
If this were to be fully confirmed – the results obtained in animal models and studies in humansincreasingly support this hypothesis– this would mean that the maternal gut microbiome would be able to directly influence the one present in breast milk. And this raises an unavoidable question: what role does maternal diet really play?
Feeding, modulator of the baby’s first ecosystem
There is no doubt that the composition of the gut microbiome is closely linked to diet.Several studieshave demonstrated that adiet rich in fiber, fruits, vegetables, and legumespromotes greater microbial diversity and the production ofshort-chain fatty acids. These promote intestinal permeability and have anti-inflammatory effects.
Conversely, diets rich in refined sugars or fats are associatedAt a lower bacterial diversity, a reduced presence of beneficial bacteria or an increase in pathogenic bacteria. This leads to an imbalance in the production of metabolites, which promotes the development of inflammation and metabolic complications.
Somescientific studiesindicate a correlation between the quality of the mother’s diet and the bacterial composition of the milk, as well as with the presence of certain metaboliteslipid and immunomodulatory. It was also established that the consumption of fatty acidsomega-3can influence the inflammatory profile and, possibly, the microbial community transmitted to the infant.
Long-term effects
At present, there are no clinical recommendations based on the milk microbiome. However, the scientific consensus tends to indicate that maternal diet may have effects that go beyond nutritional aspects, as it could also modulate the baby’s first intestinal ecosystem and influence its development and health throughout life.
More precisely, theintestinal colonizationearly can have an impact on the later risk of allergies, obesity, metabolic diseases and even disordersneurobehavioral.
Longitudinal studies (conducted over time) suggest that thefirst months of lifeconstitute a critical period of biological programming. This does not mean that breastfeeding is the only determining factor: other factors such as the type of delivery, the use of antibiotics, the family environment, and the social determinants of health also have a decisive influence. Nevertheless, this implies that we are dealing with an aspect of breastfeeding that, until now, has been clearly underestimated.
From scientific data to public policies
Modern pediatrics, which traditionally focused solely on aspects such as nutrition and growth, is beginning to incorporate an ecological perspective. According to this approach, the baby is no longer an isolated organism: it must now be considered as a metaorganism coexisting with billions of microorganisms. There is a bidirectional dialogue between the newborn and the microbiota through the production of specific molecules that impact its development and whether the baby remains healthy or develops a disease. And this mechanism is only beginning to be elucidated.
These new data on the composition of the microbiota in breast milk should not become a new source of pressure on mothers: not all can breastfeed and not all have access to a balanced diet. If science confirms that the mother’s nutritional quality directly influences the microbial colonization of the newborn, the response cannot be an individual responsibility. It must instead translate into policies that facilitate access for women of childbearing age to healthy food, as well as support for breastfeeding and work environments compatible with maternity.
Without a doubt, investing in maternal health also means investing in child health. And now, we know that this investment must also take into account the mother’s nutrition. The invisible — that is to say the bacteria, metabolites, and the interaction between nutrition and the microbiome — could well redefine the medicine of tomorrow.
Juan Pablo Ochoa Romo received funding from the secretariat dedicated to sciences, humanities, technology, and innovation (SECITHI/Mexico).
Ana María Salazar Martínez, Erika Navarrete Monroy, and Ivette Caldelas do not work for, advise, own shares in, or receive funds from any organization that could benefit from this article, and have declared no other affiliations besides their university positions.
–ref. The mother’s diet during breastfeeding could play a key role in her baby’s future health –https://theconversation.com/the-mother’s-diet-during-breastfeeding-could-play-a-key-role-in-her-baby’s-future-health-280878