What Role Does The Microbiome Play In IBS?

IBS is a complex syndrome that’s influenced by a range of issues and our microbiome is one very important factor.

What is the microbiome?

The human gut microbiome encompasses a range of microorganisms such as bacteria, viruses, and fungi that live within the intestinal tract. Trillions of microbes live in our bowel and make up more than 1,000 different species, outnumbering the number of cells in our body by 10 times.1

The 4 most important bacteria in the microbiome are Firmicutes (including Lactobacillus), Actinobacteria (including Bifidobacteria), Bacteroidetes (including B. fragilis) and Proteobacteria (including E. coli, Shigella, Salmonella and more).1 Some types of bacteria, such as Lactobacilli, Bifidobacteria and E. coli, have the ability to alter the immune system and can even reduce inflammation.1

Why does the microbiome matter?

Here are some reasons why the microbiome and the gut are important:1,3-5

  • Our gut microbiome maintains the integrity of the intestinal lining preventing bacteria from moving out of the gut, which can cause systemic (or widespread) inflammation.
  • The gut is home to majority of our immune system and the microbiome influences the immune system.
  • Around 90 percent of serotonin and 50 percent of dopamine is produced in the gut which are important for mood regulation.
  • The microbiome can signal to the brain and alter the production of neurotransmitters such as serotonin affecting mood.
  • An unhealthy gut can also impact the liver, which is important for a range of functions including detoxification of hormones and medications.
  • Poor gut health can lead to/is associated with food sensitivities.
  • Inadequate diet and stress can negatively impact the microbiome leading to circadian rhythm (sleep/wake cycle) disruption.
  • The microbiome is affected in many serious diseases such as cancer and type 2 diabetes.

Significant factors in the IBS process

Several factors can affect IBS, including:2

  • Dysbiosis, which is an imbalanced or altered microbiome.
  • Intestinal permeability, which is also known as ‘leaky gut.’
  • Chronic low-grade inflammation, which produces a steady level of inflammation throughout the body.
  • Changes in gut motility; motility is a term used to describe the contraction of the muscles that move contents through the gastrointestinal tract.
  • Changes to the gut-brain axis, which is the way the gut and brain talk to each other.

The microbiome in people with IBS

It’s assumed that people living with IBS have an imbalanced or altered microbiome. In fact, people with IBS have lower microbial variety and lower numbers of Methanobacteriales and Prevotella species.1

Lactobacillus and Bacteroides species, known beneficial bacteria, are also lower, while the numbers of pathogenic bacteria, such as Streptococcus spp., are higher.1 In a study of people with IBS who experienced abdominal pain, the investigators observed that people with pain had 5 times less Bifidobacteria in their intestines.1

One of the most common symptoms in IBS is abdominal distension or bloating, and gas-producing bacteria may be responsible for this.1 It occurs because gas swells the bowel, the diaphragm can’t completely relax, which pushes the abdomen outwards, leading to bloating.1

Leaky gut with IBS

It’s been identified from colon biopsies that the space between intestinal cells (or leaky gut) is significantly higher in people with IBS compared to people without IBS.2 There's also a significant link between the level of abdominal symptoms and the severity of leaky gut, especially in people with IBS-D.2 Additionally, the presence of the dysbiosis is associated with a leaky gut.2

What can you do?

Trying to find out the root cause of your gut issues will help you find a targeted treatment strategy. This means working with a health professional to find out if your symptoms are caused by small intestine bacterial overgrowth (SIBO), a food chemical intolerance or something else. But if no defining cause of your symptoms can be found, then you can support your gut health and microbiome by following some basic guidelines:

  • Consume plenty of fibre from wholefoods such as vegetables, fruit, wholegrains, nuts, seeds and legumes. Eat at least 5 servings of vegetables every day.
  • Try a soluble fiber supplement such as slippery elm or partially hydrolysed guar gum (PHGG).
  • Support your microbiome with fermented foods such as sauerkraut. Start with small amounts such as a teaspoon with a meal.
  • Drink plenty of water, at least 8 glasses per day.
  • Address food intolerances as these contribute to inflammation. If you are struggling with food intolerances, consider working with a nutritionist.
  • Avoid processed, sugary and fried foods.
  • Chew your food mindfully and slowly to assist digestion.
  • Manage your stress levels by incorporating regular exercise, meditation, yoga or spending time in nature.

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