SIBO stands for small intestinal bacterial overgrowth. It is a condition in which the level of bacteria in your intestines is higher than what is considered a healthy level.
IBS is characterised by symptoms such as a bloated feeling, abdominal pain, diarrhoea, very frequent or urgent bowel movements and gas. The number of people with IBS is likely to be around 15-45% of the global population.
SIBO can be caused by several factors, including antibiotics, diet, and stress. It is usually diagnosed through a doctor’s blood tests or stool samples.
Prevalence of SIBO In IBS
A recent systematic review found that the prevalence of SIBO in patients with IBS was between 14-39%. The study found that about one-third of the patients with Irritable Bowel Syndrome tested positive for Small Intestinal Bacterial Overgrowth.
The prevalence of SIBO in IBS is high, with up to 70% of patients showing positive breath tests for SIBO.
SIBO is most common among women, older age groups, and people with IBS and diarrhoea.
Factors Associated with SIBO Among Patients with IBS
Among patients with SIBO, women tend to have it in more significant numbers. The average age of diagnosis is increasing, and many tend to experience medical issues based on bloating and flatulence. Many people also present with IBS-diarrhoea issues.
A study found out that the factors associated with SIBO among patients with IBS were:
- A history of SIBO
- Age 40 years or older
- A lower body mass index (BMI)
- A higher level of anxiety and depression
- Excessive use of antibiotics
A total of 871 patients with IBS were evaluated for SIBO using capsule endoscopy in the Gastrointestinal Motility Lab at the University of Colorado, Denver, CO. Patients with SIBO had significantly higher BMI, lower age, and a more significant number of episodes of diarrhoea in the past three months.
Another study concluded the following factors associated with SIBO in patients with IBS:
- Age over 50 years
- Other conditions that could cause SIBO (e.g., celiac disease, Crohn’s disease, cystic fibrosis)
- History of smoking
- Alcohol abuse
- History of antibiotics
- A diet low in fermentable fibre
- History of non-steroidal anti-inflammatory drug use
- History of gastric surgery
IBS Symptoms Among Patients with SIBO
Following are the IBS symptoms among patients with SIBO:
- Abdominal pain
- Unusual stool form
- Bloating
- Distension
- Flatulence
- Vomiting
- Loose motion
- Cramps
- Diarrhoea
- Sometimes constipation
IBS SIBO Diet
There are many diets for IBS with SIBO, several options for which are outlined below:
- LOW FODMAP
A leading diet for IBS is to follow a low FODMAP diet, which will reduce gas and bloating from foods high in FODMAPs.
- SIBO DIET
The SIBO Diet is a diet that focuses on the consumption of foods that have been shown to feed the good bacteria in your gut. Foods that have been shown to help with constipation, IBS symptoms, IBS SIBO treatment, and other digestive health concerns are included in the SIBO Diet.
Nutrition, medicine, lifestyle changes, and counselling have also been found to relieve symptoms of IBS SIBO.
IBS-C and SIBO
People with IBS-C suffer from frequent gas, bloating, and abdominal pain. They also don’t often have bowel movements because they are difficult to pass. IBS-C can be very uncomfortable and often interferes with daily activities. It is the more predominant form of irritable bowel syndrome.
In order to manage the symptoms of IBS, it’s important to make lifestyle changes and use medications that specifically target your symptoms.
IBS-C and SIBO can be caused by a variety of things, including stress, gut infections, and eating a low-fibre diet.
There is no direct connection between SIBO and IBS-C. However, SIBO can cause IBS-C when the overgrowth increases methane levels, a type of gas that slows down bowel transit time.
How can you tell the difference between IBS and SIBO?
There are many symptoms of IBS and SIBO. These symptoms include bloating, pain, and even cramps that last for hours or days.
It can be challenging to distinguish between irritable bowel syndrome and small intestinal bacterial overgrowth. However, there are some characteristic differences between these two conditions.
A key way is to use the SIBO breath test to assess the bacterial load in the small intestine. This offers a clearer indication of the levels of hydrogen and methane being produced and can help us to understand the underlying cause of symptoms.
How do I know if it’s SIBO or IBS?
The symptoms of IBS and SIBO (small intestine bacterial overgrowth) are very similar. This makes it hard to know if IBS or SIBO is the cause of the symptoms.
The symptoms of IBS and SIBO are similar and include gut health symptoms such as bloating, abdominal pain as well as altered bowel movements. For some, this can include constipation or diarrhoea whereas for others, the bowel patterns may alternate between the two types of intestinal symptoms.
It is also important to understand how these 2 terms are used. IBS describes a set of symptoms, but it is important to understand the underlying cause to address the imbalances in the gut. This means that more information is often needed to understand the cause of IBS symptoms.
One possible cause of IBS symptoms is an overgrowth of bacteria in the small intestine. Some research has indicated that up to 70% of those with IBS test positive for SIBO. However, rather than an overgrowth is it also possible for there to be a general imbalance in the gut microbiome, described as dysbiosis.
One way to gather information about which gut health issue is causing symptoms is to consider testing options. These can include SIBO tests and microbiome tests as well as testing for other conditions such as coeliac disease and inflammatory bowel disease.
Can you have IBS and SIBO?
IBS and SIBO can involve the same set of symptoms and closely relate to one another. Instead of it being possible to have both IBS and SIBO, it’s helped to use these terms as a way to understand the causes of digestive and intestinal symptoms. For many, it is common for SIBO to be the cause of the symptoms of IBS such as bloating, gas and pain.
If a patient has tested positive for SIBO various treatment options are available, one of which may involve the prescription of antibiotics. These antibiotics are a treatment to lower the level of bacteria in the small intestine. However, it can be common for SIBO to reoccur if the underlying cause of the overgrowth in the small intestine has not been addressed.
These underlying causes of SIBO include:
- Low-grade inflammation
- Thyroid conditions
- Abdominal adhesions
- Medications
- Digestive enzyme insufficiencies
If following treatment for SIBO symptoms of IBS continue it may be that either SIBO was not the cause of symptoms or that another factor is contributing to IBS symptoms. This means that SIBO may be a cause of IBS in many, but there are also other possible causes of IBS symptoms.
An important consideration is that the accuracy of SIBO testing has been evaluated. SIBO testing is not 100% accurate which is another important consideration when treating IBS. Particularly, if gut health symptoms do not improve following a SIBO treatment, other possible causes of IBS symptoms should be considered.
What does a SIBO flare-up feel like?
A flare-up of SIBO feels very similar to a flare in IBS symptoms. In fact, it’s common for SIBO to be the underlying cause of IBS symptoms. This means that a flare-up of SIBO can feel the same as a flare-up of IBS.
During a SIBO flare-up, a wide range of gut health symptoms can increase or appear. This can involve an increase in symptoms such as bloating, an increase in gas and abdominal pain. It’s also common for bowel patterns to alter. For some, this may be an increase in diarrhoea or more constipation while for others the bowel can be very unpredictable leading to a back-and-forth between constipation and diarrhoea.
A flare-up of SIBO and IBS symptoms can be triggered by factors such as stress, antibiotics or food poisoning. In other cases, a SIBO flare-up can appear without any known or obvious reason. Once symptoms have flared-up they can often calm down but how long they take to calm down depends on the individual patient. For some, a flare-up can last a few hours while for others a flare-up of SIBO or IBS can last a few days or even weeks.
A flare-up can be seen as a different situation from a relapse of SIBO. More commonly with SIBO, symptoms are present to some degree on most days. Following a successful SIBO treatment, symptoms should resolve and remain this way. For symptoms to fully resolve, this is considered a successful treatment where the underlying issue has also been addressed.
However, when symptoms appear again or gradually increased following antibiotics or herbal antimicrobial therapy, it’s likely the underlying issue has not been addressed and the overgrowth of bacteria in the small bowel has reoccurred.
What are the first signs of SIBO?
The signs and symptoms of SIBO are similar to the symptoms of IBS. However, in SIBO there may be certain symptoms that indicate and point towards an overgrowth of bacteria in the small intestine.
One of the first signs of SIBO is bloating which happens very soon after eating. This can commonly be within 30 minutes of eating and may or may not be followed by an urgent bowel movement.
There are certain foods that may trigger this reaction. Commonly these foods that trigger symptoms contain FODMAPs. These FODMAPs are certain carbohydrates which may be poorly absorbed or inappropriately fermented in the small intestine.
This is due to the overgrowth of bacteria seen in the small intestine of those with SIBO impairing these digestive functions.
The most common FODMAPs to trigger reactions include:
- Garlic
- Onion
- Beans
- Lentil
- Lactose containing dairy
- Apples
- Pears
