Healthy gut microbiota contains a balanced composition of different classes of bacteria that have a number of health-promoting functions from birth to later life.
Every person’s microbiome is unique but, in general, a healthy microbiome is a diverse ecosystem with low levels of pathogens and high levels of beneficial bacteria1-4. There aren’t specific bacteria that a healthy individual ‘should’ have in their gut; bacteria are adaptable and have been shown to undertake different functions, depending on individual microbiome composition4. We are still learning about this fascinating miniature world and how babies’ microbiomes differ from those of adults.
For example, breastfed babies tend to have gut microbiomes that are less complex and are dominated by beneficial bifidobacteria, which support immune function5. In the first 1,000 days, babies move from a protected environment to one where they are exposed to lots of immune challenges, which helps the immune system to learn and adapt3. There is increasing evidence to support the so-called ‘hygiene hypothesis’ that exposure to bacteria is good for us and that if we remained in a sterile environment throughout childhood, our body’s immune system would not be able to function nearly as well.
Composition of the gut microbiota is influenced by many factors
A healthy gut microbiota contains a balanced composition of many classes of bacteria that have a number of health-promoting functions. Throughout life, in particular during infancy, the composition of the gut microbiome is very dynamic3. Factors that can affect its composition include6:
- Diet of the mother during pregnancy
- Mode of delivery (vaginal birth vs C-section)
- Gestational age, e.g. premature birth
- Nutrition, e.g. with prebiotics, probiotics or postbiotics
- Use of antibiotics
An imbalance in gut microbiota, known as ‘dysbiosis’, during infancy, can have a negative impact on health and wellbeing and has been linked to an increase in asthma and allergies, as well as infantile colic and gastrointestinal disorders1,2. It is also thought to increase the risk of obesity and metabolic disorders later in life1,2.
The human host-microbe symbiosis is initiated in early life and its establishment is an intriguing dynamic process. Research has shown that it may profoundly influence health and wellbeing throughout life3.
References
- Vandenplas Y, et al. Essential Knowledge Briefing. Wiley, Chichester (2015)
- Collado MC et al. Gut Microbes, 3(4): 352-65, 2013
- Wopereis H, Oozeer R, Knipping K et al. The first thousand days – intestinal microbiology of early life: establishing a symbiosis. Pediatr Allergy Immunol 2014; 25: 428-438
- Bull MJ, Plummer NT. Part 1: The Human Gut Microbiome in Health and Disease. Integrative Medicine: A Clinician’s Journal 2014; 13(6): 17-22
- Gueimonde M, Laitinen K, Salminen S et al. (2007) Breastmilk: a source of bifidobacteria for infant gut development and maturation? Neonatology 92, 64–66
- Munyaka P et al. Front Pediatr. 2014;2:109.
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