For nine long months, you nurtured your baby in the secure confines of your womb. Your little one was protected by your immune system and nourished by the food you ate.

After birth and out of the safety of your womb, your newborn’s various systems – including the immune system – need to function on their own. In the first few days of life, your little one’s immune system is still immature and needs time to strengthen. Some of this development is linked with your baby’s gut flora, or the microorganisms that live in your child’s digestive system.

Baby gut flora: How gut health builds baby’s immunity

We may think that all microorganisms are bad for our health. However, some bacteria, viruses and fungi are crucial for good health – and most of these inhabit the human gut, including your newborn’s. The gut is the gastrointestinal system that includes the stomach, small intestine and colon. 

At just a few weeks old, your newborn’s gut is home to a community of millions of bacteria, viruses and fungi – or gut flora. Most are helpful to the body (symbiotic), others could be potentially harmful (pathogenic). This community of microorganisms (also known as the microbiome) coexist in a healthy body without causing health issues. In fact, gut flora have an essential role in health – they stimulate the immune system and regulate the immune homeostasis.

The role of birth in establishing your baby’s microbiome

Given that the womb is sealed off and sterile in nature, you might be wondering how your newborn’s gut gets populated by these microorganisms. A large part of the answer lies in the mode of delivery. Birth is when your baby is exposed to microorganisms that then colonise your newborn’s gut. There is a difference between the kind of gut bacteria that migrate to your baby’s system during a natural delivery and a Caesarean section.

A large study² revealed that babies born naturally receive much of their gut flora from their mother, while more bacteria that are typically found in a hospital setting inhabited the guts of babies delivered through Caesarean sections. These “hospital bacteria” are also known as “opportunistic pathogens” and are often present in healthy babies without causing an issue. However, if immunity is low or these pathogens get into the bloodstream, then health issues may occur. Mums who have undergone a Caesarean section  shouldn’t worry too much though, as this difference in baby gut flora disappears when the baby is weaned.

The early years are critical: How to nurture your little one’s gut health

A large study² revealed that babies born naturally receive much of their gut flora from their mother, while more bacteria that are typically found in a hospital setting inhabited the guts of babies delivered through Caesarean sections. These “hospital bacteria” are also known as “opportunistic pathogens” and are often present in healthy babies without causing an issue. However, if immunity is low or these pathogens get into the bloodstream, then health issues may occur. Mums who have undergone a Caesarean section shouldn’t worry too much though, as this difference in baby gut flora disappears when the baby is weaned.

Other benefits of a healthy gut

In addition to contributing to a strong immune system, a healthy microbiome can help eliminate food toxins⁶ and also form important nutrients like vitamin B12. Beneficial microorganisms also assist in the digestion of complex carbohydrates.⁷ There is also a strong link between a healthy gut microbiome and the prevention and reduction of the severity of allergies, including food allergies as well as eczema.^{8, 9}

Even as you nurture your little one’s gut health, don’t forget to look after your own. You can do this by¹⁰:

References:

¹ DeWeerdt, S. How baby’s first microbes could be crucial to future health. Nature. Published on 7^th March, 2018. Accessed on 21^st February, 2022 from https://www.nature.com/articles/d41586-018-02480-6
² Hunt, K. Babies born by C-section have less of their mom’s gut bacteria. Here’s why that might be important. CNN Health. Published on 19^th September, 2019. Accessed on 22^nd February, 2022 from https://edition.cnn.com/2019/09/18/health/babies-gut-microbiome-birth-vaginal-c-section-intl/index.html)
³ Walker, R. et al. The prenatal gut microbiome: Are we colonized with bacteria in utero? Pediatric Obesity. Published on 26^th April, 2017. Accessed on 22^nd February, 2022 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5583026/
⁴ The Royal Children’s Hospital Melbourne. Probiotics for Infants and Children (Factsheet). Accessed on 22^nd February, 2022 from https://www.rch.org.au/uploadedfiles/main/content/ccch/cpr_vol22_no1_factsheet.pdf (351kb)
⁵ Tun, H. et al. Exposure to household furry pets influences the gut microbiota of infants at 3–4 months following various birth scenarios. Microbiome. Published on 6^th April, 2017. Accessed on 22^nd April, 2022 from https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0254-x
⁶ Sandrine P Claus, et al. The gut microbiota: a major player in the toxicity of environmental pollutants? NPJ Biofilms Microbiomes. Published on 4th May 2016. Accessed on 25th May 2022 from ncbi.nlm.nih.gov/pmc/articles/PMC5515271/
⁷ Harvard T.H. Chan School of Public Health. The Microbiome. Accessed on 22^nd April, 2022 fromhttps://www.hsph.harvard.edu/nutritionsource/microbiome/
⁸ Scientific American. Gut Microbes May Be Key to Solving Food Allergies. Published on 20^th May, 2020. Accessed on 22^nd February, 2022 from https://www.scientificamerican.com/article/gut-microbes-may-be-key-to-solving-food-allergies/#:~:text=Studies%20have%20further%20solidified%20the,different%20communities%20of%20gut%20bacteria.
⁹ Eczema Foundation. The gut microbiome and eczema: How are probiotics beneficial? Accessed on 22^nd February 2022 from https://www.fondationeczema.org/en/support/useful-advices/microbiome-and-eczema
¹⁰ VicHealth. How to improve your gut health. Accessed on 22^nd February, 2022 from https://www.vichealth.vic.gov.au/be-healthy/how-to-improve-your-gut-health
¹¹ MedicalNewsToday. Probiotic foods: What to know. Accessed on 25th May 2022 from https://www.medicalnewstoday.com/articles/323314

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