Beneficial bacteria and the developing gut

The beneficial bacteria in the gut, or gut flora, play an important role in infant nutrition, physiology and natural immunity. They have a range of functions including: 1-2

  • Synthesis of vitamins
  • Activation of the immune system
  • Inhibition of harmful pathogens
  • Lowering pH in the colon (harmful to pathogens)
  • Synthesis of digestive enzymes
  • Support of the gut barrier

With such a wide range of functions, it’s clear to see how the bacteria inside an infant’s gut might influence their health and wellbeing. The link between gut flora, health and disease becomes apparent from the earliest stages of life and continues as the infant grows and develops.3-4 However, a healthy gut cannot be achieved with just any bacteria. Infants need to acquire the right types of bacteria.

Acquiring the right bacteria

Initial colonisation of an infant’s gut flora is largely acquired at birth. After this initial colonisation, the composition is influenced by a complex variety of physiological, cultural, and environmental factors.5-9

Early dietary exposure has a strong influence on the composition of the gut flora.10 Breastmilk naturally contains a range of oligosaccharides – non-digestible carbohydrates that selectively stimulate the growth and activity of beneficial bacteria, such as bifidobacteria and lactobacilli.10-12 Breastfed infants are more likely to develop a gut flora dominated by these types of bacteria compared to formula-fed infants.11-12

  1. Bourlioux P et al. The Intestine and its Microflora are Partners for the Protection of the Host. Am J Clin Nutr 2003; 78: 675–683.
  2. O’Toole PW & Cooney JC. Probiotic Bacteria Influence the Composition and Function of the Intestinal Microbiota. Interdiscip Perfect Infect Dis 2008; 175–285.
  3. Martin R et al. Early Life: Gut Microbiota and Immune Developmentin Infancy. Benef Microbes 2010; 1: 367–382.
  4. Wopereis H et al. The First Thousand Days – Intestinal Microbiology of Early Life: Establishing A Symbiosis. Pediatr Allergy Immunol 2014; 25: 428–438.
  5. Parfrey Lw, Knight R. Spatial and Temporal Variability of the Human Microbiota. Clin Microbiol Infect 2012; 18 Suppl 4: 8–11.
  6. Purchiaroni F et al. The Role of Intestinal Microbiota and the Immune System. Eur Rev Med Pharmacol Sci 2013; 17: 323–333.
  7. Matamoros S et al. Development of Intestinal Microbiota in Infants and its Impact on Health. Trends Microbiol 2013; 21: 167–173.
  8. Guinane CM, Cotter PD. Role oftThe Gut Microbiota in Health and Chronic Gastrointestinal Disease: Understanding A Hidden Metabolic Organ. Therap Adv Gastroenterol 2013; 6: 295–308.
  9. Westerbeek EA et al. The Intestinal Bacterial Colonisation in Preterm Infants: A Review of the Literature. Clin Nutr 2006; 25: 361–368.
  10. Shamir R et al. Gut Health in Early Life: Significance of the Gut Microbiota and Nutrition for Development and Future Health. Essential Knowledge Briefing, Wiley, Chichester (2015).
  11. Harmsen Hjm et al. Analysis of Intestinal Flora Development in Breastfed and Formula Fed Infants by Using Molecular Identification and Detection Methods. J Ped Gastroentrol Nutr 2000; 30: 61–67.
  12. Boehm G & Stahl B. Oligosaccharides from Milk. J Nutr 2007; 137: 847s–849s.

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