Gut bacterial balance affects many different areas of health, but one of the most important to consider is the establishment of healthy gut bacterial balance during infancy. Healthy gut balance during early life is associated with protection against a range of health conditions, most notably the atopic diseases of childhood—asthma, eczema, and allergies.1 Gut balance during infancy is dependent on factors such as mode of delivery, diet, and administration of probiotics or antibiotics. This early gut microbial development primes immune function that can have life-long effects on health.

Specifics about just what constitutes gut balance are still being worked out by scientists, but in general, a high amount of beneficial bacteria, such as Bifidobacterium and Lactobacillus species, and a minimal amount of potential pathogens is what constitutes gut balance. A recent study published in the journal BioMed Central Microbiology evaluated the gut bacterial composition of children with eczema compared to healthy children at age 6 months and 18 months.2

The mothers were administered the probiotic Lactobacillus rhamnosus GG at a dosage of 10 billion colony-forming units daily beginning 2 to 4 weeks before delivery, and through breastfeeding (which, in most cases, lasted through 6 months). Fecal samples were taken at age 6 months and again when the children were 18-months old. There were no differences in gut bacteria composition at 6 months, but at 18 months, the gut bacteria of the children with eczema more closely resembled that found in adults. The children with eczema had a greater diversity of gut bacteria and a higher amount of Clostridium species while the healthy children had three times greater amounts of Bacteroidetes.

The researchers stated, “Prematurely occurring changes towards an adult-type microbiota were observed to take place in children with eczema,” and “It may be speculated that an infant-type microbiota supports adequate gut barrier function and tolerance against food allergens in an immature gut. Infant-type microbiota may fortify the normal mucosal barrier function e.g. by affecting the maturation of the gut epithelium [lining] and immune functions in an optimal way and decrease the low-grade intestinal inflammation observable in subjects with eczema.”

One reason the authors suggest as explaining the lack of difference in gut bacteria between each group at 6 months is the potential protection the children received from breastfeeding, which continued in most children through 6 months. They noted, “Thus, it seems that breast-feeding could have evened up the microbiota differences between the healthy and eczematous children and masked the eczema-associated changes, which came apparent at 18 months of age after withdrawal of breast-milk.” Had the children been breastfed longer than 6 months, perhaps they would have received further benefits.

It may be that as children’s diets change and begin to include more processed and animal-based foods and less (or no) breast milk and simple pureed vegetables, that could cause a shift in microbiota to more of an adult pattern with more clostridial species. I think the Western way of life, which does not encourage breast-feeding beyond a year, and introduces most all food types by one year of age, is creating an unnatural shift in microbiota.

It has been known for more than 30 years that children who continue at least partial breast feedings until age 3 have lower incidences of most all infectious diseases as well as asthma, allergies, and eczema. Since that is not likely to happen with the Western lifestyle, starting an infant on probiotics, fish oil, and vitamin D may help prevent this microbial shift, but I still think food and stress are primary shifters of the microbiome.

This is yet one more study that highlights the importance—and complexity—of gut bacterial composition and development in early life. Refer to my previous blogs and Brenda’s for more information on this topic, and how you can promote optimal gut balance at this critical developmental stage.


  1. J. Penders, et al., “Gut microbiota composition and development of atopic manifestations in infancy: the KOALA Birth Cohort Study.” Gut. 2007 May;56(5):661-7.
  2. L. Nylund, et al., “Microarray analysis reveals marked intestinal microbiota aberrancy in infants having eczema compared to healthy children in at-risk for atopic disease.” BMC Microbiol. 2013;13:12.