Breast milk improves babies’ microbiome health.

Breast milk improves babies' microbiome health.

Breast Milk Proteins: Nourishing the Gut Microbiome of Infants


Breast milk is widely recognized for its numerous benefits for both babies and mothers. A recent study published in Frontiers in Microbiology has shed light on yet another advantage of breastfeeding: the proteins present in mother’s milk play a crucial role in the gut health of newborns.

Dr. Ignatius Man-Yau Szeto, co-author of the study from the Yili Maternal and Infant Nutrition Institute in Beijing, China, explained, “Here we show that the concentration of certain proteins in human breast milk predicts the abundance of specific gut microorganisms in infants, which are known to be important [and] necessary for health.”

The researchers hypothesized that breast milk proteins not only directly stimulate the immune system, but also regulate the gut microbiome, which in turn affects immunity.

To investigate this relationship, the team analyzed the protein composition of breast milk from 23 Chinese mothers using ultra-performance liquid chromatography-mass spectrometry. They also examined the abundance and diversity of beneficial gut microbes in the stools of the infants.

The study focused on nine milk proteins, including osteopontin, lactalbumin, and K-casein, which have been recently found to be beneficial for the early development of infants. Co-author Dr. Ai Zhao from Tsinghua University clarified their motive, stating, “Their function and mechanisms haven’t yet been fully discovered, so we wanted to examine their potential role in regulating the microbiome of infants.”

The researchers found that the concentration of proteins in breast milk was 1.6% at 42 days after delivery and 1.2% at three months after delivery. Casein, a-lactalbumin, and lactoferrin were the most abundant proteins. Besides immunoglobulin A, which is crucial for mucous membrane immune function, the concentration of most studied proteins decreased from 42 days to three months postpartum.

The predominant bacterial genera in the infants’ gut microbiome were Bifidobacterium, Escherichia, Streptococcus, and Enterobacter. Interestingly, the researchers observed strong associations between the concentrations of breast milk proteins and two relatively rare beneficial bacteria in the gut microbiome: Clostridium butyricum and Parabacteroides distasonis—both commonly used as probiotics.

The variations in the concentration of certain proteins explained differences in these bacteria’s abundance. These bacteria play a vital role in regulating the gut, combatting inflammatory bowel disease, and countering diabetes and colon cancer.

Dr. Szeto acknowledges that more research is necessary to establish a direct causal effect. He cautions, “Our findings are based on correlations, which are not enough to establish a direct causal effect.”

Nevertheless, this study provides valuable insights into the impact of breast milk proteins on the gut microbiome and underscores their importance in early immune and metabolic development.

Breastfeeding has long been understood as an essential practice for providing optimal nutrition and immunity to infants. According to the World Health Organization (WHO), breastfeeding provides vital nutrients, promotes healthy brain development, protects against infections, reduces the risk of allergies, and contributes to the establishment of a healthy gut microbiome.

The composition of breast milk is a dynamic and complex blend of proteins, fats, carbohydrates, antibodies, enzymes, and hormones. It is specifically tailored to meet the nutritional requirements of a growing infant, providing ideal ratios of nutrients and antibodies necessary for immune defense.

In addition to its nutritional benefits, breast milk helps establish a healthy gut microbiome in infants. The gut microbiome refers to the community of microorganisms, including bacteria, fungi, and viruses, residing in the gastrointestinal tract. This microbiome plays a crucial role in digestion, metabolism, immune system development, and overall health.

Breast milk serves as a source of beneficial bacteria that populate the infant’s gut and supports the growth of a diverse and balanced microbiome. These beneficial bacteria, such as Bifidobacterium and Lactobacillus species, contribute to the colonization of the gut and provide protection against harmful pathogens. They also help strengthen the immune system, reduce inflammation, and support nutrient absorption.

The recent study emphasizes the role of breast milk proteins in shaping the gut microbiome. Proteins such as osteopontin, lactalbumin, and K-casein demonstrate potential benefits for the early development of infants. Further research is needed to fully understand these proteins’ mechanisms and functions, but their impact on regulating the microbiome is evident.

By establishing connections between breast milk protein concentrations and specific bacteria like Clostridium butyricum and Parabacteroides distasonis, the researchers demonstrate the complexity of breast milk’s impact on the gut microbiome. These bacteria have been associated with various health benefits, including improved gut health, reduced inflammation, and protection against certain diseases.

Understanding the relationship between breast milk proteins and the gut microbiome opens up new possibilities for interventions to support infant health. Targeted supplementation or modifications to breast milk composition could potentially enhance the development of a healthy gut microbiome in infants, providing long-lasting benefits for their overall well-being.

It is essential to note that breastfeeding is not always possible for every mother and baby. In cases where breastfeeding is not an option, alternative sources of nutrition, such as donor breast milk or appropriately formulated infant formula, can be considered. These alternatives aim to provide similar benefits to breast milk, including the promotion of a healthy gut microbiome.

In conclusion, breast milk continues to reveal its remarkable properties in supporting infant health. The interplay between breast milk proteins and the gut microbiome highlights the intricate ways in which breastfeeding contributes to immune and metabolic development. While further research is needed, these insights pave the way for potential interventions that can optimize infant nutrition and well-being. Breast milk is truly nature’s gift, offering a unique blend of nourishment that cannot be replicated.