The first breast milk produced by mothers shortly after delivery, known as colostrum, is rich in bioactive compounds including microbes to seed the infant’s gut microbiome. However, little is known about the degree to which this transfer of microbiota from mother to infant continues throughout the breastfeeding period. The EU-funded MAMI (page in Spanish) project set out to increase our knowledge of this process and the factors affecting maternal microbiota. “This idea started when I became a mum,” explains project coordinator María Carmen Collado. “Everyone was focused on my baby, but what about me? Maternal microbes, breast milk, maternal diet, everything that happens to the mum is reflected in the baby.” There is extensive evidence of factors shaping infant microbiota, but little is known about which factors modulate the maternal microbiota during gestation and lactation. “Alteration in maternal microbiota would be reflected in the infant microbiota, with consequences for short- and long-term health outcomes,” notes Collado.
“Breast milk is more than just nutrition,” says Collado. “It contains bioactive components, including immune substances such as cytokines, hormones, and also, bacteria, their metabolites and oligosaccharides that are not used by humans, but provide bacteria with food.” The composition of breast milk changes constantly, adapting to the infant’s requirements. To understand this process better, Collado and her colleagues at the Spanish National Research Council (CSIC) recruited 250 mothers and their newborns and followed them for the first 24 months of the infants’ lives. The researchers collected data on microbiota, diet, infant growth, biomarkers, health outcomes such as allergies, and more. “This work allowed us to identify that the maternal diet is really important to shaping the microbiota of the infant,” adds Collado. “We need to learn how to take care of our microbes during the crucial periods in human life: pregnancy, lactation and early life.”
Promoting adequate microbiomes
Collado hopes that the work will allow clinicians to offer new dietary guidance for expectant mothers in terms of microbial composition. “While we have recommendations to avoid specific foods during pregnancy, nobody is telling us how to take care of our microbiome,” she notes. The next step, she says, is to describe the functionality of each microbial species, which will allow researchers to quantify the level of dysfunction in a microbiome and better understand which species can be added to fill any gaps. Furthermore, the development of food supplements, functional foods and other therapies based on microbial replacement and modulation, to promote adequate microbiota transfer to neonates, would be valuable for healthy development of the neonatal microbiome. These advances would offer new tools for both mother and neonates to modulate the microbiota mainly in those cases where antibiotics, unbalanced diet or lack of breastfeeding practices alter the microbiota. The project was supported by the European Research Council. “For me this was a dream – it allowed me to build my team, to research my own ideas, and of course opened up other projects,” remarks Collado. She is now studying the microbiota of premature infants, as well as studying how the maternal microbiota changes during pregnancy, and how these changes are reflected in foetal and neonatal development.
MAMI, breast milk, infant, mother, microbiota, transfer, diet, bacteria, breastfeeding, development