Does FMT Have The Potential to Treat SIBO

June 6, 2023

SIBO is a condition that affects bacteria in the small intestine, causing symptoms like bloating and diarrhea. Fecal microbiota transplantation (FMT) has not yet been studied for SIBO but its effectiveness in treating other microbiome related conditions suggest that it could soon be explored as a treatment for SIBO.

We will explore the potential of FMT for SIBO in the following sections.

  • What is SIBO and what causes it?
  • The connection between the microbiome and SIBO
  • Are fecal transplants a treatment for SIBO?
  • FMT for CIPO relieves SIBO

Before we jump into the possibility of FMT to treat SIBO, let’s break down what exactly SIBO is.

What is SIBO and what causes it?

SIBO stands for Small Intestine Bacterial Overgrowth and it is a disease involving excessive bacteria in the small intestine. SIBO occurs when bacteria from the stomach and large intestine make their way to the small intestine, grow and eat up resources meant for the microbes of the small intestine.

This may result in weight loss and malnutrition in its sufferers, among other symptoms such as indigestion and gas.

What are the causes of SIBO?

SIBO occurs when bacteria from other parts of the gut start to grow in the small intestine. The bacteria present can start to eat up nutrients and cause malnutrition in SIBO sufferers. Though there is no known cause of the bacterial overgrowth, certain conditions may predispose you to developing it. They include:

  • Crohn’s disease
  • Diabetes
  • Celiac Disease
  • Hypochlorhydria
  • IBS
  • Scleroderma
  • HIV
  • Parkinson’s disease
  • Hypothyroidism
  • A stomach virus or bacterial infection
  • Disturbances in the small intestine, ie. by medical procedure
  • Medications that slow down the gut activity

SIBO has also been associated with pH changes in the bowel, a compromised immune system and issues with the muscular functions of the small intestine.

What are the signs and symptoms of SIBO?

The symptoms of SIBO are almost entirely restricted to the gut. Symptoms of SIBO are characterized by their persistence and their appearance is often onset by the consumption of irritating foods.

  • Stomach pain, particularly after eating
  • Bloating
  • Gut cramping
  • Diarrhea
  • Constipation
  • Indigestion
  • Persistent feeling of fullness
  • Gas
  • Weight loss

Common SIBO treatments

The common first step in treating SIBO is antibiotic use. Antibiotics are prescribed to control the growth of the unwanted bacteria in the small intestine. Many find relief from symptoms by following specialized diets. Probiotics may also be prescribed in an attempt to regulate the bacteria in the gut.

Though antibiotic use can provide temporary relief from the condition, they won’t address the underlying issue causing the invasive bacteria leading to recurrence in many people with the condition. In fact all the current treatments of SIBO are not particularly effective long term solutions for the condition. FMT presents potential long term relief of the symptoms of SIBO.

The connection between the microbiome and SIBO

The microbiome plays a key role in human health and the upset of microbial balance in the body can lead to a plethora of health issues. Many diseases associated with SIBO are linked to dysbiosis of the gut, but it has not yet been determined if SIBO itself, is also affected by dysbiosis of the microbiome.

The microbiome’s role in the body

The microbiome is communities of bacteria, protozoa, viruses and fungi that exist on and inside our bodies. They play crucial roles in the function of our digestive system, immune system and even the functions of our brains. Microbiomes exist within niches, for example there is a gut microbiome, oral microbiome and skin microbiome.

The microbiome’s role in SIBO

Microbiome dysbiosis is common in many of the comorbidities common with SIBO. Dysbiosis of the gut microbiome may itself be a contributing factor to the small intestine bacterial overgrowth. There is growing  evidence to suggest that there may be a link, but more research is needed to understand this interplay.

Are fecal transplants a treatment for SIBO?

There have been no studies on FMTs efficacy for treating SIBO. Though SIBO is associated with a lot of conditions that have been found to respond to FMT. And because SIBO effects bacteria within the small intestine, and FMT is used to balance the microbiome, it is not a stretch to think FMT might be worth studying.

What are fecal transplants?

FMT is a treatment in which stool is taken from a healthy donor and implanted into the gut of a sick person. Fecal transplants work by engrafting the colon of a sick person with good bacteria from the donor. The good bacteria then has the potential to help balance the bacteria in the gut, reversing dysbiosis.

How may FMT treat SIBO

As SIBO often has comorbidities that are microbiome related, treating SIBO symptoms with FMT may be a possibility. FMT is used to treat dysbiosis in the gut microbiome and SIBO itself is a form of microbiome dysbiosis. The question that must be answered before FMT can be considered for SIBO is what causes it in the first place, as of yet the mechanism of how SIBO occurs is not well enough understood.

FMT for CIPO relieves SIBO

A study looking at the efficacy of fecal transplants for the treatment of chronic intestinal pseudo-obstruction (CIPO), of which 30% of patients also suffer from symptoms of SIBO, was performed at Nanjing University’s School of Medicine. In the study 9 patients received FMT through nasojejunal (NJ) tubes for 6 consecutive days and were followed for 8 weeks after.

The studies results state that SIBO was eliminated in 71% of the subjects. Though the study was undeniably very small and the focus was not particularly on SIBO, it is interesting that SIBO in most of the CIPO patients was relieved.