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A new study on Danish infants suggests that breastfeeding (and when it is ceased) is the nutritional element with the most significant effect on the development of the child’s gut bacterial population, termed the microbiota. The study, from researchers in the National Food Institute, Technical University of Denmark, and the University of Copenhagen, shows that the child’s intestinal microbiota changes significantly between the ages of 9-18 months, following cessation of breastfeeding and introduction of other foods. However, the evolution of the child’s gut microbiota continues up to the age of three. The study is published in the journal Applied and Environmental Microbiology.

Previous studies suggest that babies who are breastfed grow marginally more slowly and are a little slimmer than non-breastfed babies. This appears to translate into slightly lower incidence of obesity, allergies, diabetes and inflammatory bowel disease later in life. The composition of the gut microbiota is now recognised to be important in these conditions. The new study suggests that breastfeeding has a beneficial effect on the gut microbiota early in life which could influence how the microbiota evolves and help explain its apparent health benefits.

In the study, the research team took faecal samples from 330 healthy Danish infants at 9, 18, and 36 months after birth. They used a technique called quantitative PCR to establish the bacterial species present and their relative quantities. The results showed that breastfeeding encouraged the presence of lactobacilli, a type of bacteria that is of benefit in immune system development. Cessation of breastfeeding heralded a change in the microbiota to a population dominated by Clostridium spp. and Bacteroides spp. Evolution and stabilisation of the microbiota continued up until the age of 3 years in many children. Senior author Tine Rask Licht explains the significance of this finding: "The results help to support the assumption that the gut microbiota is not - as previously thought - stable from the moment a child is a year old. According to our study important changes continue to occur right up to the age of three. This probably means that there is a 'window' during those early years, in which intestinal bacteria are more susceptible to external factors than what is seen in adults."

The results of this study suggest biotechnological advances and public health interventions could be used to develop strategies to promote healthy gut microbiota. Tine Rask Licht explains the possibilities in terms of both breastfeeding and baby formula milk: "The results from the study can be used to support initiatives that can be used to help children develop a type of gut microbiota, which is beneficial for the immune system and for the digestive system . This could for example be advice to mothers about breastfeeding or the development of new types of infant formula to promote the establishment of beneficial bacteria in the gut."

Sources:

Bergström, A., Skov, T.H., Bahl, M.I., Roager, H.M., Christensen, L.B., Ejlerskov, K.T., Mølgaard, C., Michaelsen, K.F. and Licht, T.R. (2014). Establishment of Intestinal Microbiota during Early Life: a Longitudinal, Explorative Study of a Large Cohort of Danish Infants. Applied and Environmental Microbiology, Vol. 80, No. 9. (1 May 2014), pp. 2889-2900, doi:10.1128/aem.00342-14

Press release: Technical University of Denmark; available at http://www.food.dtu.dk/english/News/Nyhe...C24ED68377 [Accessed 8 May 2014]