Could SIBO be the cause of the 'reflux' symptoms you are experiencing?
SIBO as a diagnosis is very often over-looked and this is particularly the case in patients complaining of reflux symptoms. It is probably far more common than usually perceived and in our view should be considered in all patients thought to have gastro-oesophageal reflux disease. However, it is always important to seek medical advice and to exclude alternative causes for symptoms if necessary.
It is normal that literally billions of bacteria and other micro-organisms live in symbiosis with us in the large bowel (colon). However, the small bowel which lies between the stomach and the colon is relatively sterile. It is known that SIBO occurs when the small bowel becomes colonised by abnormal numbers of micro-organisms and these can then cause a variety of symptoms. These tend to ferment carbohydrates, particularly those high in so-called FODMAPs and during this process produce hydrogen gas which can be detected in the breath. The condition can be associated with other diseases which in turn can cause symptoms themselves. It is also likely that SIBO is a specific type of “dysbiosis”; a condition in which the usual balance of micro-organisms in the gut (the gastro-intestinal micro-biome) which is so important for good health is disrupted and that others which we currently are not able to test for almost certainly can cause symptoms and possibly illness.
One of these is now recognised as “Intestinal Methogenic Overgrowth” or IMO. In this dysbiosis rather than bacteria organisms called archaea (Methanobrevibacter smithii) produce excess methane rather than hydrogen gas.
In this short video Mr Nick Boyle, Medical Director at RefluxUK, talks about SIBO and how it related to the reflux symptoms patients present with.
There are thought to be many reasons why SIBO and other dysbiosis develop but the most likely are:
SIBO and other dysbiosis conditions can cause an enormously wide and variable set of symptoms. It is recognised that SIBO can be associated with Irritable Bowel Syndrome (IBS) in which patients can experience alternating loose stools and sometimes constipation and flatulence associated with abdominal bloating and pain. Indeed, studies suggest that when tested, up to 70% of people with "IBS" will have co-existent SIBO. It is thought that hydrogen producing organisms tend to be associated with diarrhoea while IMO and methane production with constipation. SIBO can cause vitamin especially B12 deficiency and iron deficiency anaemia and malabsorption syndromes possibly due to inflammation of the lining of the gut and poor fat digestion. Some patients complain of “Brain Fog”. In fact SIBO has been associated with more than 100 other conditions including interstitial cystitis, hypothyroidism, fibromyalgia and skin pathology such as rosacea and eczema to name just a few.
However, it is less well recognised that SIBO can be the cause of reflux symptoms. Commonly SIBO causes bloating after eating especially carbohydrates as these are fermented into gases. Sometimes people mistakenly think they may be gluten intolerant. There can be associated abdominal discomfort, particularly in the upper left side, with belching and flatulence as well as “indigestion” type symptoms. These are frequently attributed to “functional dyspepsia” in which no under-lying cause is identified and often treated with PPIs for reflux which can paradoxically exacerbate symptoms.
In our experience SIBO is most frequently associated with Laryngo-Pharyngeal (LPR) symptoms. You can read more about LPR/Silent reflux here. Belching of an aerosol of stomach contents up into the oesophagus and to the throat can cause a sore throat, post-nasal drip, throat clearing, a sensation of a lump in the throat (globus), voice problems as well as others. This aerosol may contain hydrochloric acid as well as the powerful enzyme Pepsin and Bile. However, other reflux symptoms including regurgitation, heartburn and respiratory symptoms can all be associated with intestinal dysbiosis. There is also some evidence that constipation can increase the frequency of so-called Transient Lower Oesophageal Relaxations (TLOSRs) which are associated with reflux and so use of laxatives can sometimes help reduce reflux symptoms. Since IMO is associated with constipation this may be another mechanism by which intestinal dysbiosis causes reflux symptoms.
The most accurate method to test for SIBO is to take aspirates from the duodenum (the first part of the small bowel after the stomach) and then culture these to see which bacteria grow. This is invasive and impractical and so we use breath tests. You'll be sent a kit so you can do the test at home. You'll swallow a sugar solution and then breathe into a series of small bottles over two hours. You'll then send the kit back to us and we'll analyse the contents of the bottles to measure hydrogen and methane gases. If you have SIBO and/or IMO in which micro-organisms in the gut metabolise the sugar solution into these gases, their concentration in the exhaled breath will be higher than normal.
It can sometimes be difficult to establish whether SIBO is a secondary phenomenon caused by PPIs correctly used to treat true reflux or rather the primary cause of symptoms. Consequently, it is usually necessary to exclude primary gastro-oesophageal reflux disease as part of a collection of tests which assess the anatomy and physiology of the stomach and oesophagus. These may include endoscopy, manometry and reflux studies.
The treatment of SIBO can be difficult and even the most effective treatment regimens can fail.
We see many people with co-existent reflux and SIBO symptoms who are taking PPIs. They may have been prescribed these because of reflux symptoms and then developed SIBO which exacerbates their reflux symptoms. Eradicating SIBO while continuing to take PPIs is unlikely to be effective if the PPIs are its cause and stopping these in the context of significant reflux symptoms can be equally difficult. Many people take PPIs for obscure reasons and often their reflux can be better treated with dietary modification, different drugs or even surgery.
Having eliminated an identifiable and treatable cause of SIBO the main pillars of treatment are dietary modification to deprive the responsible bacteria of their food, anti-biotics to destroy the unwanted bacteria and pro-biotics to re-establish a normal gastrointestinal bacterial flora. Sometimes drugs which improve gastro-intestinal motility will also be used in the treatment regime which should be tailored to each patient individually. Currently the evidence is that Rifaxamin will eradicate SIBO in 70% of patients. It is the most effective anti-biotic and since its effect is largely confined to the small bowel it has a minimal effect on the colonic micro-biome. For these reasons we would not advise the use of less specific wide-spectrum anti-biotics. When IMO is diagnosed we usually add a second anti-biotic called Neomycin which is especially effective when used with Rifaxamin rather than in isolation.
Ultimately, the key to success is making the right diagnosis and treating each patient as an individual. At RefluxUK we understand how debilitating "functional" gut symptoms including those caused by reflux and SIBO can be. We will work with you to agree a tailored approach to diagnose and treat your symptoms, provide you with specialist medical and dietician advice and hopefully achieve the best likelihood of eliminating them.
If you think that SIBO may be a cause of your symptoms, contact us today to find out more and arrange a consultation with one of our specialist doctors.
Page reviewed by: Mr Nicholas Boyle BM MS FRCS 01/11/22
This short online questionnaire is designed to measure the severity of your SIBO symptoms. We'll calculate your SIBO 'score' and send you a free personalised report.SIBO symptom checker