The Making of the Gut Microbiome

Microbial Colonization Begins at Birth

Initial colonization of the gut microbiome occurs at birth.10,11 Delivery type—vaginal or cesarean—strongly influences how the gut microbiome develops.10-12

The gut microbiome of a newborn who was delivered vaginally is initially populated with the commensal vaginal and fecal microbiota of the mother.11,12 In contrast, after cesarean delivery, the gut microbiome is primarily colonized by the mother's skin microbes.10,12

Differences in gut microbial composition based on delivery type can be seen for up to seven years. Although a causative link has not yet been established, differences associated with cesarean delivery have been connected to the development of certain childhood autoimmune diseases, including11:

  • Celiac disease
  • Asthma
  • Type 1 diabetes mellitus
The First Three Years

Additional factors that affect the development and colonization of the gut microbiome early in life include10-12:

  • Feeding method (breast milk vs formula)
  • Weaning (timing of the introduction of solid foods)
  • Genetics (a small but notable contribution)
  • Antibiotic use during the first three years of life

In three years, the composition of a child's gut microbiome resembles that of an adult's.12

Into Adulthood

A healthy gut microbiome is relatively stable and resistant to disturbances.6,13 However, shifts in microbial composition can occur over time due to5,9,14:

  • Age
  • Illness
  • Diet
  • Other environmental influences
microbiota acquired at birth from vagina and mother’s skin, and microbiota acquired during breastfeeding
microbiota acquired at the introduction of solid food, such as indigestible carbohydrates
microbiota acquired in western diet high in fats and animal protein, and in traditional diet high in fiber and carbohydrates

Adapted, with permission, from: Tanaka M, Nakayama J. Development of the gut microbiota in infancy and its impact on health in later life. Allergol Int. 2017;66: 515-522.


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