3 new studies support importance of early life for the gut microbiome
In recent months there have been several pieces of research published in medical journals about both the importance of the gut microbiome in infanthood, and also factors that affect its development.
Shortly after birth bacteria take up residence within an infant’s gastro-intestinal tract. The initial inoculation of probiotic bacteria should ideally come during the birth itself, as the baby takes in a gulp of its mother’s flora during its journey down the birth canal. Subsequent to the birth the infant is exposed to many different sources of bacteria (both good and bad), that take up ‘residence’ in the intestines.
A look at the research:
Study into breast versus formula feeding:
A recent review 1, published in ‘Parental nutritional metabolism and health and disease of offspring’ looked at the impact of either breast-feeding or bottle feeding in the development of an infant’s gut flora. The review looked at many different studies, and summarised that both exclusive and partial formula feeding of infants has a negative impact on the gut microbiome. This method of feeding appears to increase pro-inflammatory bacteria (such as Proteobacteria), increase intestinal permeability and reduce levels of beneficial short-chain-fatty-acids in the colon. Breast-feeding on the other hand appears to increase levels of protective anti-inflammatory bacteria from the class Actinobacteria, and reduces intestinal inflammation.
The study concluded however that further research was needed to determine the impact on health of introducing formula to breastfed infants for only brief periods of time, for example using formula milk only on an occasional day if the mother’s milk supply was inadequate that day. Research has not yet been carried out to understand the amount of formula feeding that can be tolerated before the infant's gut flora is negatively affected, but it is recommended that newborns should be exclusively breastfed for the first six months of life wherever possible.
Study looking at the impact of daily exercise:
A second new study 2 by a team of researchers at the University of Colorado, and published in ‘Immunology and Cell Biology’ showed that exercising in early life can also alter and improve the microbial community in the gut. The study found that juvenile rats who voluntarily exercised every day developed a healthier gut microbiome, with a higher proportion of probiotic strains of bacteria than compared to their sedentary counterparts. This trend is also observed in human subjects, however researchers have not yet isolated an exact age range during which time the daily exercise must be performed in order to achieve the benefits to gut flora, however it has been supposed that the ‘earlier the better’. So, maybe the trend for baby yoga classes brings even more benefits than just a ‘blissed out’ baby then, perhaps even their gut microbes are enjoying the work out...
The study authors go on to state that they ‘emphasize the ability of exercise during this developmentally receptive time to promote optimal brain and metabolic function across the lifespan through microbial signals.’ With this statement the authors are also supporting the theory of ‘psychobiotics’ (the ability of gut bacteria to influence our emotions and mood), which I have written about previously. To read more about how our gut microbes affect the way we think and feel, click here.
Study linking colic to imbalanced gut flora:
The first two studies I have discussed have given evidence of different factors which affect the development of our juvenile gut flora (both the consumption of human breast milk, and the participation in daily exercise), however a third review 3 concentrates on one of the many possible consequences of an unhealthy infant gut flora, namely a predisposition towards colic.
The integrative review gave a synopsis of findings from five recent studies, and concluded that according to the existing evidence it appears that infants that express symptoms of colic were colonized with significantly higher levels of Proteobacteria, and had significantly reduced bacterial diversity, when compared to control subjects that did not have colic symptoms. Additionally, excessive crying in newborns correlated with low levels of beneficial Actinobacteria and Bifidobacteria species in their intestines.
I think I am spotting a recurring theme here. High levels of Proteobacteria, and low levels of Actinobacteria were two of the findings already mentioned in the first study looking at formula fed versus breast fed infants, so when looking at the results from both studies in conjunction it could be summised that bottle fed infants could be at a higher risk of colic and excessive crying than breast fed infants. I wonder if there could be any better incentive for a new mum to breast feed her newborn than the promise of a good nights sleep?!
Looking after our children's health:
I write regularly about new research in to the microbiome, however I am particularly pleased by this current flurry of research focusing more specifically on the developing microbiome of infants. After all, health begins in the gut, so what better way can there be to ensure a healthy life for our children than by really understanding the impact of dietary and lifestyle choices on their gut flora, and intestinal health.
To read more about the impact of gut flora on child's health, click on the following links:
(1) The Influence of Early Infant-Feeding Practices on the Intestinal Microbiome and Body Composition in Infants. Aifric O’Sullivan, Marie Farver and Jennifer T. Smilowitz. Nutrition and Metabolic Insights 2015:Suppl. 1 1-9
(3) Characterizing the Intestinal Microbiome in Infantile Colic. Findings Based on an Integrative Review of the Literature. Nancy E. Dubois, MSN, RN1, Katherine E. Gregory, PhD, RN2 1Boston College, William F. Connell School of Nursing, Chestnut Hill, MA, USA, 2Harvard Medical School, Pediatrics, Brigham and Women’s Hospital, Boston