A grey graphic of the human bowels.
Studies show that gut dysbiosis affects 75% of people with IBS.

How Are Gut Dysbiosis and IBS Related?

Gut dysbiosis is a problem that is common among people with IBS. It occurs when the population of bacteria and other microorganisms living in the digestive tract becomes imbalanced.

In this article, we explain what gut dysbiosis and the relationship between gut dysbiosis and IBS. We also talk about how to treat and prevent it. Here’s all you need to know.

What Is Gut Dysbiosis?

Our bodies are home to trillions of microorganisms, including bacteria, viruses, fungi, and more. They are known as the microbiome and exist in especially high concentrations in areas like the skin and gut.

Some of these organisms are beneficial, while others are potentially dangerous. However, providing that the population of helpful organisms outweighs the harmful ones, we remain in a state of good health.

Unfortunately, sometimes the balance of these microorganisms gets thrown out. This situation is what scientists refer to as dysbiosis. It can cause a variety of symptoms depending on where in the body it occurs.

When there is dysbiosis in the gut, it can lead to digestive problems, including irritable bowel syndrome (IBS). So, what is the exact relationship between gut dysbiosis and IBS? Let’s take a closer look.

How Is Gut Dysbiosis Related to IBS?

According to some studies, gut dysbiosis affects as many as 75% of people with IBS. However, it is unclear whether gut dysbiosis causes IBS or the other way around.

It appears that people with IBS have fewer beneficial microorganisms in their digestive tracts than healthy individuals. They may also have less variety of species.

Conversely, these people are also at high risk of developing a condition called small intestinal bacterial overgrowth (SIBO). It may be that they do not have enough beneficial bacteria to keep the harmful ones under control.

Another possible explanation is that, following an infection, bacteria remains in the digestive system. The result is gut dysbiosis and something known as post-infection IBS.

Gut dysbiosis can cause several issues in the digestive tract. It alters the way that the gut contracts, increases the permeability of its walls, and increases sensitivity to pain. Some sources also suggest gut dysbiosis could lead to inflammation and dysfunction in how the gut communicates with the brain. All of these factors can lead to the classic symptoms of IBS.

Symptoms of Gut Dysbiosis and IBS

People suffering from gut dysbiosis and IBS may experience a variety of symptoms:

  • Gassiness
  • Bloating
  • Abdominal pain
  • Irregular bowel movements

Additional symptoms of gut dysbiosis:

  • Bad breath
  • Stomach upsets
  • Chest pain
  • Nausea
  • Diarrhea
  • Constipation
  • Rashes
  • Fatigue
  • Reduced concentration
  • Anxiety or depression

Gut Dysbiosis Risk Factors

There are many different factors that can upset the delicate balance of the microbiome and cause gut dysbiosis:

  • Diet changes
  • Medication
  • Toxins (e.g. pesticides on fruit and vegetables)
  • Infections (bacteria, viruses, fungi, etc.)
  • Excessive alcohol consumption
  • Poor dental hygiene
  • Unprotected sexual intercourse

Genetics and changes in the immune or nervous system may also play a role. It is unclear whether having IBS is a risk factor for having gut dysbiosis in itself.

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What Are the Treatment Options?

There are several treatment options available for gut dysbiosis and IBS:


If there are too many harmful bacteria living in the gut, antibiotics can help to get them under control. However, it is essential to use the correct antibiotics as some could damage good bacteria as well as bad. One popular option is rifaximin, which appears to be especially helpful for people with IBS.

Probiotics and Prebiotics

Most people have heard of probiotics. They are foods or supplements containing live bacteria, for example, live yogurt and fermented foods, like sauerkraut or kimchi. Probiotics can help to restore harmony to the microbiome and may be beneficial for some people with IBS.

Prebiotics are less well-known, but are also essential for maintaining a healthy microbiome. They are indigestible carbohydrates that probiotics use as food. They help to increase numbers of helpful bacteria and reduce potentially harmful ones.

Some supplements are known as synbiotics, meaning that they contain both probiotics and prebiotics.

Diet Changes

Including more prebiotic and probiotic foods in the diet can reduce bacteria that contributes to gut dysbiosis and IBS.

Foods to eat:

  • Dark green, leafy vegetables (kale, spinach)
  • Fish (salmon, mackerel)
  • Fresh meat
  • Fermented foods
  • Live yogurt

Foods to avoid:

  • Processed meat
  • Dairy
  • Gluten
  • High-sugar foods
  • Alcohol
  • High FODMAP foods

It can be challenging to get the balance right between managing symptoms and getting enough nutrition. Therefore, it is best to consult a knowledgeable dietician before making any significant changes.

Fecal Microbiota Transplant

Fecal microbiota transplants involve taking a sample of stool from a healthy donor and inserting it into the patient’s gut. They are not suitable for all types of gut dysbiosis and there are certain risks involved. Therefore, they are often seen as a last resort when other treatments have failed.

Gut Dysbiosis Prevention Methods

Some of the best ways to prevent gut dysbiosis for people with or without IBS:

  • Eating a microbiome-friendly diet as detailed above
  • Wash food well before eating to remove toxins
  • Reduce alcohol consumption
  • Take prebiotic and probiotic supplements if necessary
  • Wash the hands regularly, especially after using the bathroom and before handling food
  • Maintain good dental hygiene
  • Always practice safe sex by using a condom or dental dam

By following these guidelines, it should be possible to prevent gut dysbiosis. In many cases, this could also have a positive impact on IBS and its symptoms.