A recent study, led by Dr. Tine Rask Licht, head of the Research Group for Microbiology and Immunology from the National Food Institute at Technical University of Denmark, found that the development and establishment of the infant gut microbiota at 9 months of age is primarily driven by the transition to family foods, independently of maternal obesity.


The first 3-5 years of life represent the most critical period for dietary interventions to improve child growth and development, as during this period the intestinal microbiota is established. To shed light on the impact of maternal obesity and dietary factors such as breastfeeding and complementary diet composition on infant gut microbiota development, the researchers compared the gut microbiota of two different cohorts of Danish infants: those born to normal-weight healthy mothers (n = 114) and those born to obese mothers (n = 113). Faecal samples were obtained at 9 and 18 months of age. Infants’ anthropometry and body composition were also measured. Infant diet was recorded by parents at the age of 9 months using validated 7-day food records. Furthermore, information on sex, socioeconomics, prevalence of C-section, gestational age at birth, prior use of antibiotics and other medications, duration of exclusive and total breastfeeding, and age of introduction to complementary feeding were also collected from parental background interviews at the 9- and 18-month-old visits.


Within-sample and between-sample diversity of the gut microbiota in the two cohorts changed over time, while maternal obesity per se did not impact gut microbiota development. The mode of delivery, gestational age at birth, and the use of oral antibiotics during the 2 weeks before sampling had limited influence on gut microbial diversity at 9 or 18 months. Infants from normal-weight healthy mothers were breastfed significantly longer than infants from obese mothers. Interestingly, the duration of exclusive breastfeeding (0 to 6 months) was associated with increased abundance of specific bacterial taxa at 9 months of age, and this was more noticeable in infants born to healthy mothers. In both cohorts, bacterial species that are involved in degrading plant-derived fibres and resistant starch in solid foods were negatively affected by the duration of exclusive breastfeeding. However, positive correlations with exclusive breastfeeding were observed in both cohorts for Bifidobacteriaceae (which utilize both lactose and oligosaccharides found in breast milk) and Veillonellaceae (which are considered lactate-degrading bacteria). Besides this, the effects of breastfeeding on microbial composition were limited at 18 months of age. On the other hand, the timing of introduction of complementary (solid) foods (3 to 6 months) did not correlate with gut microbial composition during late infancy.


Based on the infant diet recorded by parents at the age of 9 months, the transition from early infant foods to foods introduced in late infancy with higher protein and fibre content correlated with increased gut microbiota diversity, thus suggesting that this progression to more nutritionally diverse family foods is a major driver of gut microbial changes during late infancy.


Although these results show that gut microbiota composition is correlated with the dietary patterns during late infancy, the researchers could not link microbiota composition to any health differences in the infants. Thus, it does not yet have clinical implications.


In conclusion, introduction of family foods with higher protein and fibre content may be considered the main driver of infant gut microbiota development at 9 months of age. “Until now nobody has addressed the effect of diet at his age. We found that the food determines the diversity and the composition of the microbiota, and this is very important”, says Professor Licht.



Laursen MF, Andersen LBB, Michaelsen KF, et al. Infant gut microbiota development is driven by transition to family foods independent of maternal obesity. mSphere. 2016;1(1):e00069-15. doi:10.1128/mSphere.00069-15.