- What is the microbiome?
- How does our microbiome impact our health?
- How can we best keep it nourished?
These are all very good questions!
Rachel Carson, ecologist and author of the game-changing book Silent Spring in 1962, was right in more ways than one when she said: “In nature, nothing exists alone”. We humans live in a symbiotic relationship with a massive number of microbes that dwell within us.
The trillions of microbes inhabit our intestines form a complex ecological ‘community’ that influences our normal body-functioning and susceptibility to disease. For decades, we humans have recognized that we are inhabited by a remarkably dense and diverse microbial ecosystem, yet we are only just beginning to understand and appreciate the many roles that these complex communities play in our health and development.
The human microbiome refers to the community of more than 1 trillion microscopic organisms living in and on us through our lifetime—10 times the number of our own cells[i]. These organisms and their genetic material, influence all manner of human physiology – certainly not limited to protecting our gut lining, impacting our digestion and bowel function.
Adult humans carry up to two kilograms of microbes in our gastrointestinal tract (this is weightier than our brain!) [i], [ii]. Our own personal gut ‘microbiota’, or microbial community, is immensely diverse, is unique to us, and can fluctuate over time — especially during disease and early development.[iii]
Recent advances in genomic sequencing technologies and analysis are providing a broader understanding of these resident microbes, and the tremendous expansion of information collected in recent years is a result of data generated through large-scale endeavours such as the NIH-funded Human Microbiome Project HMP. Scientific interest in how the microbiome might be manipulated through diet, supplements and lifestyle to improve health and treat disease has exploded in recent years.
The gut flora has been shown to influence brain development[iv], behavior[v], mood, immune system development[vi], cancer risk[vii], and cardiovascular disease[viii], as well as many factors that influence body weight such as insulin production[ix], appetite, metabolism[x], inflammation, and more.
The development of the gut microbiota
To mirror the million dollar debate of “Nature vs Nurture”, as it turns out, both genetic and environmental factors shape our unique gut microbiota. To start from the start, for decades, doctors were taught that the womb environment was sterile — that the amniotic sac, and the fluid that surrounded the baby, was a uniquely pristine environment devoid of any bacteria in order to protect the growing baby, which still doesn’t have a fully developed immune system. The conventional wisdom was that the baby’s first exposure to bacteria began during birth, from the mother’s birth canal, and continued through the infant’s skin-to-skin contact with mom and from its new environment.
But in recent years, scientists have been able to detect small amounts of bacteria in the amniotic fluid and in the placenta, and even in the foetus’ intestines, supporting the idea that the baby’s microbiome actually gets established far earlier than thought, in the womb.
The infant microbiome is particularly impressionable. A baby’s gut microbiota, for example, can be influenced by the style of delivery, by breastfeeding, by the introduction of solids, diet, and by antibiotics exposures – all of these factors plus more can have an impact on their immune expression and health outcomes. Scientists continue to explore the still-mysterious world of microbes in the developing child – watch this space.
Signs of an unhappy microbiota
Bloating, diarrhea, indigestion and food intolerances can all be caused by an imbalance between the beneficial and detrimental bacteria colonies. Factors that can interfere with healthy adult microbiome include:
- Chronic stress
- A highly processed, high protein diet [xi]
- High sugar intake, high refined carbohydrates[xii]
- Preservatives in foods, such as sulphates and sulphites[xiii]
- Oral contraceptive pill
- Toxins of choice – alcohol[xiv] (alcohol produced a brief, but large increase in the microbe species that were pro-inflammatory, stimulating the immune system as if it were under attack and contributing to the general sick-feeling so typical of hangovers)
- Some medications such as PPI’s prescribed for acid reflux.
All of the above contribute to an imbalance in favour of destructive bacteria. Once the thin mucous membrane has been penetrated by bacteria, and/or the contributing behaviour continues, a host of digestive disorders ensues.
The more diverse our gut bacteria, the better
As they say, variety is the spice of life 😉 A diverse gut microbiome is a key to good health. And harbouring a healthy ecosystem results in good gut integrity and immune resilience.
Reduced microbial diversity is associated with an increased risk of allergies, obesity, insulin resistance, irritable bowel symptoms, inflammatory processes, and even chronic fatigue syndrome[xv].
Can we alter our gut microbiota?
Since the gut microbiome is influenced by the food we eat and the environment around us, it makes sense that there are ways to make it healthier.
We can protect and nurture our microbiome by using foods that establish and nourish a robust gut ecosystem. Foods known as prebiotics ‘fertilise’ the gut’s friendly microbes. Foods such as asparagus, artichoke, beans, garlic, leek, root vegetables, and other plant foods rich in fibre are prebiotics. Plant foods reign when it comes to keeping our internal communities strong. Enjoying towards five cups of a variety of vegetables daily not only promotes regular bowel movements, but also ensures a flourishing microbiome.
Limiting stress, and avoiding unnecessary use of pharmaceuticals is also critical to gut health. Use of a high quality, multi-strain probiotic after a course of antibiotics is a critical consideration to help you restore a healthy balance.
This is a very exciting time in the study of the microbiome. If this topic is of interest to you, and you feel you’d like some personalised support based on your unique circumstances, we at awaken your health are only a phone call away.
In celebration of these complex ecological ‘communities’ that live within us, I would like to remind you that there are many people writing on this topic. Here are just a few resources that you may find interesting:
[i] Palmer, C., Bik, E. M., DiGiulio, D. B., Relman, D. A., & Brown, P. O. (2007). Development of the Human Infant Intestinal Microbiota. PLoS Biology, 5(7), e177. http://doi.org/10.1371/journal.pbio.0050177
[ii] Johnson, C. L., & Versalovic, J. (2012). The Human Microbiome and Its Potential Importance to Pediatrics. Pediatrics, 129(5), 950–960. http://doi.org/10.1542/peds.2011-2736
[iii] Catherine A. Lozupone C, et al. (2012) Diversity, stability and resilience of the human gut microbiota. Nature 489, 220–230.
[iv] Sampson TR, Mazmanian SK. Control of brain development, function, and behavior by the microbiome. Cell Host Microbe. 2015 May 13;17(5):565-76.
[v] Sampson TR, Mazmanian SK. Control of brain development, function, and behavior by the microbiome. Cell Host Microbe. 2015 May 13;17(5):565-76.
[vi] Kau, A. L., Ahern, P. P., et al. (2011). Human nutrition, the gut microbiome, and immune system: envisioning the future. Nature, 474(7351), 327–336.
[vii] Schwabe, R. F., & Jobin, C. (2013). The microbiome and cancer. Nature Reviews. Cancer, 13(11), 800–812.
[viii] Griffin JL, Wang X, Stanley E. Does our gut microbiome predict cardiovascular risk? A review of the evidence from metabolomics. Circ Cardiovasc Genet. 2015 Feb;8(1):187-91.
[ix] Okeke F, Roland BC, Mullin GE. The role of the gut microbiome in the pathogenesis and treatment of obesity. Glob Adv Health Med. 2014 May;3(3):44-57.
[x] Janssen AW, Kersten S. The role of the gut microbiota in metabolic health. FASEB J. 2015 Aug;29(8):3111-23.
[xi] S H Duncan, et al. Human colonic microbiota associated with diet, obesity and weight loss International Journal of Obesity (2008) 32, 1720–1724.
[xii] Hawrelak JA1, Myers SP. The causes of intestinal dysbiosis: a review. Altern Med Rev. 2004 Jun;9(2):180-97.
[xiii] Hawrelak JA1, Myers SP. The causes of intestinal dysbiosis: a review. Altern Med Rev. 2004 Jun;9(2):180-97.
[xiv] Bala S, Marcos M, Gattu A, Catalano D, Szabo G (2014) Acute Binge Drinking Increases Serum Endotoxin and Bacterial DNA Levels in Healthy Individuals. PLoS ONE 9(5): e96864. doi: 10.1371/journal.pone.0096864
[xv] Ludovic Giloteaux, Julia K. Goodrich, et al. Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome. Microbiome20164:30
[i] Human Microbiome Project C A framework for human microbiome research. Nature. 2012 Jun 14;486(7402):215–21. PubMed PMID: 22699610. Pubmed Central PMCID: 3377744.