A recent study investigated whether bacterial colonization of the gut starts with the transfer of bacteria in breast milk from mother to child. Evidence suggests that bacterial colonies found in breast milk are transferred to the infant, providing protection against certain autoimmune diseases and the development of obesity.
Our intestines are home to a wide assortment of bacteria that start to colonize within days after birth. These bacteria have a symbiotic relationship with our bodies, helping us with various processes such as digestion and immune system responses. The composition of bacteria living in our gut changes over the first few years of our lives, until it mimics an adult like composition by the age of 3. From previous research, scientists have noted that any disruptions to the normal course of bacterial development in the gut can result in autoimmune disorders such as diabetes and inflammatory bowel disease. Due to the importance of proper bacterial colonization on future health, the researchers of this study wanted to further explore this concept, specifically looking at the possibility of bacterial transfer from breast milk to the infant gut.
A study published in JAMA Pediatrics assessed the association between maternal breast milk and infant gut bacteria in 228 participants, including 107 mother-infant pairs. The participating infants ranged in age from 0 days to 1 year. Further requirement for selection included that both mothers and infants were in good health, and that infants had no prior exposure to antibiotics. At the initial visit, information was collected from the mothers, including facts about pregnancy, medication use, as well as infant feeding. Then, samples of breast milk and swabs from the areolar skin were taken from the mothers and analyzed. Additionally, stool samples from infants were collected and analyzed.
The findings of the study suggest that there is bacterial transfer from breast milk to the intestines of the infant. The most compelling evidence comes from comparing the bacterial composition of an infant with its mother compared to random mother from the study. The data indicates that the bacterial lineage is more consistent between mother and infant than between a random mother and the infant. Additionally, the research found that in the first month after birth, breast milk provides 40% of the bacteria living in an infant’s gut. Analysis of the bacteria suggests that it is involved in processes related to energy metabolism. In fact, breastfeeding has been associated with decreased odds of obesity in the children. Lastly, the data also suggests that bacterial diversity is affected by different factors including the age of the infant and the introduction of solid food to the diet.
This research provides new insight into the process of bacterial colonization of an infant’s gut. However, further research will be needed to continue our understanding of this process and to pinpoint the exact source of the bacteria in breast milk.
Written By: Sonia Parmar, BSc