SIBO supplements – Dietitian Review

Many ‘SIBO supplements’ are available to purchase, despite a lack of evidence to support the claims that they can treat SIBO. 

Small Intestinal Bacterial Overgrowth (SIBO) is an overgrowth of bacteria in the small intestine that results in gastrointestinal symptoms (1). 

The main symptom of SIBO is severe bloating due to the fermentation of carbohydrates by bacteria in the small bowel.

SIBO treatment aims to kill the overgrowth of bacteria in the small bowel.

Many SIBO supplements claim to:

• Increase the efficacy of SIBO treatment (e.g. improve the effectiveness of antibiotics) 
• Manage symptoms of SIBO (such as bloating)
• Support digestion using digestive enzymes 
• Improve gut motility

This article will discuss the theory behind the claims for various SIBO supplements and whether or not there is any research to support this.

Activated charcoal 

Activated charcoal is more sponge-like after exposure to high levels of heat and oxidising gas or other chemicals. It is commonly used in healthcare to treat toxicity from certain drugs and poisons (2).

Some claim that activated charcoal can treat SIBO due to its binding properties. You may hear some people say that activated charcoal can bind to bacteria in your small bowel and promote their excretion, treating SIBO. 

Sadly, these claims remain unproven, so we cannot recommend activated charcoal to treat SIBO.We discuss activated charcoal further in our post ‘Does Activated Charcoal Help IBS Symptoms?’.

Partially hydrolysed guar gum (PHGG)

PHGG is a soluble fibre supplement with prebiotic properties. Prebiotics are types of fibre that feed the good bacteria in our gut, helping them to grow.

You can read more about them in our post ‘What Are Prebiotics and Should You Be Taking Them?‘.

One study found that Rifiaxmin for SIBO treatment was more successful with PHGG alongside it than Rifaximin alone (3). 

This was a small study, and the results were not clinically significant.

This means that the results did not meet the calculated level that proves the supplementation of PHGG was responsible for improving SIBO treatment in this group. 

This means the improved outcome in the group with PHGG could have been due to chance. However, PHGG supplementation is something that you can try alongside your antibiotic treatment if you want to.

One study showed that PHGG improved bloating (4), a predominant symptom of SIBO. Participants in this study did not have proven SIBO; therefore, there is no evidence that you can use PHGG alone to treat SIBO.

Digestive enzymes 

Digestive enzymes are another supplement you may come across when searching for SIBO treatment. However, these are not recommended. 

SIBO is linked to diarrhoea and, in rare cases, related to malabsorption (5).

This is because the bacteria in the small bowel can deconjugate bile acids, which can result in bile acid malabsorption (BAM). BAM can then go on to cause fat and fat-soluble vitamin malabsorption.

However, in this case, digestive enzymes will not manage BAM; a type of medication called a bile acid sequestrant will be advised.

This will control bile acid malabsorption but is not a SIBO supplement or treating SIBO.

Digestive enzymes have good evidence for use in specific digestive conditions, but they are not helpful for SIBO.

For example, in pancreatic enzyme insufficiency (PEI), you must take prescribed enzyme supplements containing amylase, lipase and protease.

Herbal supplements / Iberogast

Some studies suggest that herbal supplements such as dysbiocide and FC Cidal and Candibactin-AR and Candibactin-BR may improve SIBO (6).

However, we discuss the limitations of this research in our post ‘Can You Take Herbal Supplements for SIBO?“. 

The theory is that herbal supplements, such as garlic and oregano, come from their antimicrobial properties. Allicin is a component of garlic and available to buy as a supplement. 

However, test tube studies and not human studies demonstrated these properties. So we have no evidence that they can kill the types and quantities of bacteria in SIBO. 

Commercial herbal supplements are also not regulated, and therefore, you can not be sure of the concentration of each herb in the product.

You may have heard that Iberogast is a natural herbal remedy used for SIBO.

The theory behind this is that Iberogast can act as a motility agent (7), which means that this would promote bacteria from moving through the gut and prevent overgrowth in the small bowel.

There have not been any studies that have shown Iberogast can manage SIBO. However, Iberogast can improve pain in IBS (8), as discussed in our post ‘Will Iberogast Help IBS Symptoms?’.

Probiotics 

The use of probiotics alongside antibiotics has shown to be more effective at treating SIBO than antibiotics alone (9). But there is not enough research yet to support the idea that probiotics can treat SIBO on their own.

The exact mechanism of how probiotics alone or alongside antibiotics can help SIBO is unknown; therefore, more research is needed.

Sadly, we don’t know which probiotics should be used alongside antibiotics. Instead, we suggest you use a specific probiotic for your underlying condition or symptom.

If you have IBS, then you can check our post-Probiotics for IBS.

Biofilm disruptors 

When some groups of microbes populise, they produce a layer known as a biofilm.

A biofilm helps protect bacteria by allowing them to stick to the surface and protect them from the immune system and antibiotics (10).

Natural compounds such as phenolics and essential oils may be recommended as natural biofilm disruptors.

However, natural biofilm disruptors have failed clinical trials to support their use as a biofilm disruptor medication. This may be due to poor availability in the human body once taken (11). 

A review found that one biofilm disruptor, N-acetylcysteine, can help improve the efficacy of antibiotic treatment of certain infections such as H. Pylori (12).

However, more research is needed for this, and as of yet, no trials suggest that this can help improve antibiotic response in SIBO.

Other biofilm disruptors available to buy include enzymes, but again, these have no evidence of working in SIBO.

Peppermint oil 

Peppermint oil is an antispasmodic. This is because it helps the gut muscle to relax, easing bloating and cramps.

Peppermint oil has good evidence for helping manage these symptoms in IBS, which you can read more about in the post ‘Peppermint Oil Capsules and IBS – Do They Work?’.

You can try peppermint oil as a SIBO supplement to help manage stomach pain and bloating. However, it will not treat your SIBO.

Summary

SIBO supplements you might find online include PHGG, activated charcoal, herbal supplements and probiotics, to name a few. 

Despite the variety of SIBO supplements available online, minimal research supports their use. 

SIBO treatment and SIBO supplements need further research; therefore, antibiotics are currently the most effective, evidence-based treatment.

You could try supplementing your antibiotic treatment with PHGG or probiotics, which you can discuss with a Registered Dietitian.

Article written by Bethany Willson, Specialist Gastroenterology Dietitian, reviewed by Kirsten Jackson, Consultant Dietitian BSc Hons, RD, PG Cert