The strong connection between the gut microbiome and our physical and mental health is becoming widely appreciated. Over a thousand different species of gut bacteria are in constant communication with the rest of the body, including the brain, the skin, and the immune system.
What happens in the gut doesn’t stay in the gut, so to speak.
In addition, a wealth of research is emerging showing how disturbances within the gut microbiome can contribute to a number of health conditions including inflammatory bowel diseases (IBD), irritable bowel syndrome (IBS), diabetes, obesity, cancer, cardiovascular and neurological disorders1https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566439/2https://pubmed.ncbi.nlm.nih.gov/30535609/
Gut dysbiosis is something you may hear about a lot so let’s look into it in more detail –
Gut dysbiosis vs a balanced microbiome
First, let’s consider what a healthy and balanced gut microbiome looks like. A diverse and abundant community of gut microbes provides a wealth of health-giving substances (postbiotics) to its host; it nourishes the gut lining and maintains a protective mucus layer along the gut wall whilst preventing the overgrowth of harmful bacteria and keeping inflammation at bay. It’s a tall order but gut bacteria have the genetic capabilities to do it. However, this ecosystem can be disturbed by environmental factors, including diet, stress, and antibiotics, resulting in dysbiosis.
The definition of gut dysbiosis is an imbalance in the gut microbiome which can lead to negative health outcomes. Gut dysbiosis is characterised by all or a combination of the following:
- Reduced microbial diversity
- A loss of beneficial bacteria
- An overgrowth of harmful bacteria
Consequences of gut dysbiosis:-
- Disruption to the gut lining and protective mucus layer.
- Disturbance to the immune system and increased inflammation.3https://www.frontiersin.org/articles/10.3389/fendo.2021.667066/full
- Changes to metabolism such as nutrient absorption, appetite control, and insulin function.4https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8954387/
How does gut dysbiosis come about?
Your genes contribute to the composition of your gut bacteria, which in turn can influence the development of gut dysbiosis. However, environmental factors, including diet, lifestyle, and exposure to antibiotics, play a more crucial role in shaping the gut microbiome.5https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9321451/ Thankfully, these factors are also the ones you have some control over – so let’s look at these in more detail:-
- A diet low in dietary fibre, and high in processed foods and sugar increases inflammation and promotes the growth of harmful bacteria.6https://www.sciencedirect.com/science/article/pii/S2352289516300509
- Lack of physical activity is shown to reduce microbial diversity in the gut.7https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6987436/
- Stress – Chronic stress affects the gut-brain axis and negatively influences the composition of the gut microbiome.8https://www.sciencedirect.com/science/article/pii/S2352289516300509
- Antibiotic use – broad-spectrum antibiotics can kill both harmful and beneficial bacteria in the gut, leading to an imbalance.
- Nicotine – cigarette smoking, including e-cigarettes, plays a significant role in gut dysbiosis.9https://www.frontiersin.org/articles/10.3389/fendo.2021.667066/full
- Infections – many infectious diseases, even if they are not gastrointestinal, can trigger dysbiosis of the gut microbiome e.g. Covid-19.10https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8954387/
- Hygiene practices – either picking up harmful bacteria through poor hygiene or through excessive hygiene that can lead to a reduction in good bacteria.11https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/antibacterial-cleaning-products
Keep an eye out for part 2 which will cover how gut dysbiosis is linked to various health conditions.
If you’d like to read more on gut health, check out these articles – Signs of an unhappy gut – and what you can do about it!, Biofilm – The Beauty and the Beast, Meet your very own commensal bacteria!
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