Establishing a Resilient Ecosystem: The role of the breast microbiome

Establishing a Resilient Ecosystem: The role of the breast microbiome

The first 1000 days of life, from conception to age 2, provide a narrow window of opportunity for your growing baby to build a healthy and resilient microbiome. This vast and invisible ecosystem exists inside and outside the body and plays an important role in supporting a child's growth and development now and in the future. [1] Just as Earth’s ecosystems maintain a healthy planet, our microbiome maintains a healthy “us.”

Research shows that building your baby's microbiome depends heavily on your own microbial health. Ecosystem sharing between mothers and babies can occur through a variety of pathways, including the birthing process, skin-to-skin contact, and a relatively recent discovery called the enterothoracic axis. [2]

This precious microbial connection between you and your baby highlights the importance of taking care of your microbiome throughout pregnancy, breastfeeding, and more. [1]

Yet despite this important discovery, many expectant mothers are unaware of their microbiome, what it is and how to care for it.

That's why we've broken down this important information to help you better prepare for this special and important time in your (and your baby's) life. 

What is the enterothoracic axis?

It seems like every other day a new discovery puts the gut microbiome at the center of our health. Recent research has identified several pathways that exist between the gut microbiome and different systems in the body, including: 

Gut-brain axis 

Gut-skin axis

Gut-liver axis

Gut-heart axis[3]


And it is likely that there are many more gut organ axes that have yet to be discovered.

In each of these pathways, the gut can communicate with distant organs, sending messages that affect health and function. [3]

The gut-breast axis is no different.

Hormonal changes throughout pregnancy prepare the gut and breasts for the needs of the growing baby. Changes in the gut help increase the absorption and absorption of nutrients, and changes in the breast allow these nutrients to be delivered to the baby through breast milk. [1][4]

Together, the gut and the breast form a close partnership with a common goal; to replace the placenta and provide nutrition for the baby after birth.

Breast milk: A shared ecosystem[5]

Breast milk is a complex and nutrient-dense food source. In addition to providing an ideal nutritional balance, breast milk contains many other bioactive components, such as immune cells, hormones, and microbes, which work together to support early growth and development in infants. Breast milk is rich in human milk oligosaccharides (HMOs), a preferred food source for beneficial microorganisms and an ideal habitat. [6]

The journey from gut to breast

In addition to microbes from topical skin and breast tissue, microbes in breast milk are also thought to originate from the mother's gut. [2]


Recent research has identified a unique pathway by which microbes can enter breast milk directly from the mother's gut, primarily through hitchhiking maternal immune cells. This pathway forms part of the gut-milk axis and explains how gut microbes are found in breast milk samples. [7]


Mastitis: An imbalanced ecosystem?[8]

A balanced breast milk microbiome allows for the direct delivery of a diverse mix of beneficial microbes to the infant gut, with additional benefits for the infant's oral microbiome in the process.

However, a variety of factors, including genetics, ruptured nipples, and blocked ducts, can contribute to an imbalance in the breast microbiome. This in turn can lead to a condition called mastitis. [8]

What is mastitis?

Mastitis is a condition that causes breast pain and swelling, making breastfeeding difficult. It is a common disorder that affects 5-33% of breastfeeding women and is associated with early weaning, a potentially distressing experience for both mother and baby. [8][9]

How do you treat mild mastitis?

Mild mastitis can be resolved with self-management techniques, including:

     -   Self-massage

     -   Feeding on the affected side

     -   Cold compress – such as the traditional remedy of cold cabbage leaves [9][10]

For moderate-to-severe mastitis, it is best to consult your health professional.

Can you prevent mastitis?

While genetics can play a role, mastitis is also linked to lifestyle factors, including high stress, tight clothing, and missed meals. [8][9] Seeking breastfeeding support, as well as taking care of your overall physical and mental health, may help prevent recurrent mastitis.

The role of probiotics

Probiotics are defined as live microorganisms that provide health benefits similar to those provided by beneficial microorganisms that are naturally present in the human body. [1]

Lactobacillus fermentum CECT5716 is a specific strain of probiotic bacteria in breast milk that may also have health benefits when used as a probiotic supplement. Research suggests that Lactobacillus fermentum CECT5716 may help relieve mild symptoms of mastitis while breastfeeding. [4][11]


Putting it all together

Taking care of your microbial health during pregnancy, breastfeeding, and more will help not only keep you healthy, but your newborn as well.

In addition to probiotic supplements, a combination of a healthy diet and lifestyle may help support a healthy breastfeeding experience, allowing you and your baby to enjoy this precious journey while laying the foundation for supporting health and well-being.


[1] Robertson RC, Manges AR, Finlay BB, Prendergast AJ. The human microbiome and child growth–first 1000 days and beyond. Trends in Microbiology. 2019 Feb 1;27(2):11-47.

[2] Rodríguez JM, Fernández L, Verhasselt V. The gut‒breast axis: Programming health for life. Nutrients. 2021 Feb;13(2):606.

[3] Ahlawat S, Sharma KK. Gut–organ axis: a microbial outreach and networking. Letters in applied microbiology. 2021 Jun;72(6):636-68.

[4] Mesa MD, Loureiro B, Iglesia I, Fernandez Gonzalez S, Llurba Olivé E, Garcia Algar O, Solana MJ, Cabero Perez M, Sainz T, Martinez L, Escuder-Vieco D. The evolving microbiome from pregnancy to early infancy: A comprehensive review. Nutrients. 2020 Jan;12(1):133.

[5] Pannaraj PS, Li F, Cerini C, Bender JM, Yang S, Rollie A, Adisetiyo H, Zabih S, Lincez PJ, Bittinger K, Bailey A. Association between breast milk bacterial communities and establishment and development of the infant gut microbiome. JAMA pediatrics. 2017 Jul 1;171(7):647-54.

[6] Wiciński M, Sawicka E, Gębalski J, Kubiak K, Malinowski B. Human Milk Oligosaccharides: Health Benefits, Potential Applications in Infant Formulas, and Pharmacology. Nutrients. 2020;12(1):266. Published 2020 Jan 20. doi:10.3390/nu12010266

[7] Hurtado JA, Maldonado-Lobón JA, Díaz-Ropero MP, Flores-Rojas K, Uberos J, Leante JL, Affumicato L, Couce ML, Garrido JM, Olivares M, Fonollá J. Oral administration to nursing women of Lactobacillus fermentum CECT5716 prevents lactational mastitis development: A randomized controlled trial. Breastfeeding Medicine. 2017 May 1;12(4):202-9.

[8] Contreras GA, Rodríguez JM. Mastitis: comparative etiology and epidemiology. Journal of mammary gland biology and neoplasia. 2011 Dec;16(4):339-56.

[9] Wilson E, Woodd SL, Benova L. Incidence of and risk factors for lactational mastitis: A systematic review. Journal of Human Lactation. 2020 Nov;36(4):673-86.

[10] Kataria K, Srivastava A, Dhar A. Management of lactational mastitis and breast abscesses: review of current knowledge and practice. Indian Journal of Surgery. 2013 Dec;75(6):430-5.

[11] Maldonado-Lobón, Jose A., Miguel A. Díaz-López, Raffaele Carputo, Pilar Duarte, Maria Paz Díaz-Ropero, Antonio D. Valero, Ana Sanudo et al. "Lactobacillus fermentum CECT 5716 reduces Staphylococcus load in the breastmilk of lactating mothers suffering breast pain: A randomized controlled trial." Breastfeeding Medicine 10, no. 9 (2015): 425-432.

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