Why is my baby’s gut health important?

Snapi Health
4 min readJan 19, 2022

Gut health has been a popular topic for adults lately — but what about gut health in infants? Children’s guts develop comparably to an adult’s gut by age three. This post explores how an infant’s gut develops and what influences their gut health.

The human body hosts a party of microorganisms — and millions of microorganisms are invited in the first year of life. This is because infants with minimal gut bacteria in their microbiome. More research is finding that a baby’s first few months of life is a critical time period for their healthy microbiome development.

What’s a “Microbiome”?

The human microbiome is the genetic material of all microbiota that live on and inside the body. The vast majority of microbiota reside in the gut, mainly in the large intestine. Our microbiome helps us digest and metabolize food, regulates and maintains our immune system, synthesizes important vitamins in our body, and protects us against pathogens. Interestingly, there is growing evidence that the gut microbiome influences certain developments in the brain, including cognitive and emotional/social development. Infants are born with a very immature microbiome and immune system that are in need of development.

Different microbiota begin to colonize an infant’s intestines at different stages. Imagine that you’re building a zoo — in the beginning, you only have a penguin exhibit, for example. The “penguins” are the minimal microbiota the baby is exposed to in utero. Then at birth, the baby is exposed to more microbiota through the vaginal canal, environment, and skin contact — now your zoo has elephants, giraffes, and monkeys in addition to the penguins. Next is breast milk and formula, which provide the baby’s gut with even more new microbiota (and more animal exhibits at your zoo). And finally, starting solid foods introduces lots of new microbiota; enriching your zoo with even more new animals. Now your zoo has a big, healthy diversity of animal exhibits — just like how a baby’s gut develops a big, healthy diversity of microbiota.

Factors that influence a baby’s gut microbiota

Vaginal vs surgical birth: The vaginal canal hosts a huge diversity of good bacteria that infants who are born vaginally get exposed to at birth. Infants born surgically via cesarean section are exposed to different bacteria, and to a lesser extent. Regardless of how a baby is delivered, there are still ways that parents can improve their baby’s microbiome. If babies miss the bacterial opportunity from the vaginal canal at birth, then lots of immediate mom and baby skin-to-skin contact can help transfer some additional good bacteria to the baby. When a vaginal birth is possible and safe to do, it’s the preferred birthing method in terms of microbiota exposure.

Breastfeeding vs formula feeding: Studies have shown that one of the best ways to develop a baby’s microbiome is by breastfeeding exclusively for the first 6 months, when possible. Breastfeeding is one way that C-section babies can “catch up” in terms of their microbiome development because breast milk delivers a variety of the mother’s microorganisms to the infant. One example is the human milk oligosaccharides (HMOs) found in breast milk; HMOs are a carbohydrate that infants are unable to digest, therefore they pass into the intestines and act as a probiotic by stimulating the growth of good bacteria. Breast milk also contains immunoglobulins (antibodies) that help develop a baby’s immune system. Infant formula provides a variety of good bacteria as well, however, research has found that breastfed infants develop a more optimal diversity of gut microorganisms.

Weaning onto solid foods: The timing of introducing solid foods is key. The gut microbiome can be altered by foods if they are given before the gut is ready to handle them. Thus, digestive problems are more likely to happen if foods are introduced too early. 6 months is typically the best age to start complementary solid foods because the baby will be both developmentally and physiologically ready. As a baby’s solid food intake increases, so does his/her gut microbiome diversity and amount.

Antibiotic influence: Antibiotic exposure may have a negative impact on a fetus’ gut microbiota development. Women who may need antibiotics during pregnancy or lactation should discuss options with their healthcare provider.

There’s more where that came from…

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  1. Stewart CJ, Ajami NJ, O’Brien JL, et al. Temporal development of the gut microbiome in early childhood from the TEDDY study. Nature News. https://www.nature.com/articles/s41586-018-0617-x. Published October 24, 2018. Accessed July 26, 2021.
  2. Tanaka M, Nakayama J. Development of the gut microbiota in infancy and its impact on health in later life. Allergology International. https://www.sciencedirect.com/science/article/pii/S1323893017301119#:~:text=Although intestinal bacterial colonization begins,two big transitions in infancy. Published October 2017. Accessed July 26, 2021.
  3. Yang I, Corwin EJ, Brennan PA, Jordan S, Murphy JR, Dunlop A. The infant microbiome: Implications for infant health and neurocognitive development. U.S. National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681407/. Published January 2017. Accessed July 26, 2021.

About the Author

Dana Schechner is a Registered Dietitian Nutritionist and Lactation Counselor who is passionate about sharing credible, science-backed information. Dana is a true foodie!

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