The study builds on existing theories that believed the infant gut was sterile, only undergoing colonisation after birth primarily influenced by the maternal microbiota, diet, and the environment.
These new findings reveal that infants born via caesarean section (CS) had a delayed colonisation of Bifidobacterium by up to three months. The bacterial species bacteroides had a delay of at least six months.
The type of feeding in the first three months of life and its influence on the microbiota composition at six months was also looked at.
The researchers found that infants born by vaginal delivery (VD) who were breastfed were most often colonised by B.bifidum and the L. gasseri subgroup, compared to those exposed to formula feeding (mixed feeding) or born by CS.
Additionally this study revealed that at birth girls were six times more frequently colonised by the L. ruminis subgroup at birth, four times by L. gasseri subgroup and three times by L. reuteri subgroup from two days to three months after birth.
The findings, published in the latest edition of Public Library of Science (PLOS) One, may provide new insights into the effectiveness of current nutritional supplements available that claim to support the developing infant gut microbiome.
Studies have indicated that formula supplementation provides an able substitute to mothers, who are unable to produce sufficient amounts of breast milk. This method has also proved effective in settling a fussy baby ensuring that they get enough sleep.
In contrast, there is also research that has shown breastfed and formula-fed infants demonstrate significant differences in their respective gut microbiota, which may affect function and bacterial diversity.
Faecal study
The study, which was funded by Yakult and Nutricia Research, began by taking faecal samples from 108 healthy new born babies, who were in the first six months of life.
Analytical techniques were used to assess the composition and capabilities of the microbiota. At this stage 33 different bacterial taxa and eight bacterial metabolites were identified.
Information about the babies’ diets and mode of birth were also recorded, along with gender, presence of siblings or pets; and antibiotic use via questionnaires.
Regression analysis techniques were used to estimate the relationships among variables, in this case the microbiota and confounding factors over time.
“Early life is especially important because this is where the symbiosis between the microbiota and the host is shaped,” said professor Jan Knol, director gut biology and microbiology platform at Nutricia Research and lead author of the study.
“In this first phase in life the interaction of the colonising microbes with the developing gut (epithelium), immune and metabolic systems are thought to be specifically important for a healthy development.”
The development of the infant gut microbiota has been the subject of numerous studies all looking into the influence of the host genotype, gestational age, antibiotic use, mode of delivery, diet and the environment in which the infant was born (rural vs urban, presence of siblings, pets and other factors)
Additionally, previous studies have demonstrated that bacteria from the mother are given to the infant’s gut in a vaginal delivery (VD). Infants born by CS may be initially colonised by bacteria from the environment such as from maternal skin, hospital staff or even other neonates.
Gut’s broad influence
Knol, who also works at Wageningen University in the Netherlands, added that the influence of the microbiome went far beyond the gut. Indeed, the maturation of the immune system at an early age was a critical determinant of future health.
“A lot of scientific data indicates that all physiological systems (immune, metabolic, brain) can be more or less influenced by the microbiota. We need to do proper human studies to understand the full potential of microbiota modulators (like prebiotics and probiotics) on many different disease outcomes.”
“This may indeed open new strategies and concepts for influencing the early microbiome supporting a healthy start in life.”
Source: Public Library of Science (PLOS) One
Published online ahead of print, doi.org/10.1371/journal.pone.0158498
“Early-Life Events, Including Mode of Delivery and Type of Feeding, Siblings and Gender, Shape the Developing Gut Microbiota.”
Authors: Rocio Martin, Jan Knol et al.