Could SIBO be causing your IBS?

SIBO – Some of you may have heard of this but most may not and it has become important in identifying one of the underlying causes of irritable bowel syndrome (IBS).  In recent years SIBO has also been linked with fibromyalgia, acne rosacea and other health problems which is why it is a fascinating condition to diagnose and treat. Before you rush out to your GP, getting tested is not simple and it is not widely available on the NHS. SIBO is currently mostly diagnosed privately, some GP’s have never heard of the condition and some consultants are dubious as to it’s relevance in relation to IBS and other related health issues. In essence it is still quite controversial but if you would like to find out more, please read on as it may be one of the answers to your unanswered health problems.

What is SIBO? 

Small Intestinal Bacterial Overgrowth is a chronic bacterial infection of the small intestine. The infection is due to bacteria that normally live in the gastrointestinal tract but have abnormally overgrown in a location not meant for so many bacteria. The bacteria can interfere with our normal digestion and absorption of food. It can also lead to deficiencies in iron and vitamin B12, causing certain anaemias.

After eating food, the bacteria produce gas within the small intestine which in turn can cause abdominal bloating, abdominal pain, constipation, diarrhea or both. This can get confusing because of course these are the symptoms of irritable bowel syndrome (IBS).  SIBO has been shown to exist in up to 84% of IBS patients. However for my part, I have not seen this higher percentage and I find about 30% of IBS patients have a positive SIBO test. Apart from IBS, SIBO has been linked controversially to a whole host of other conditions. These include:

Other symptoms

  • Heartburn (Reflux or GERD)
  • Weakness
  • Weight loss
  • Nausea
  • Food Sensitivities
  • Headaches
  • Joint Pain
  • Fatigue
  • Skin symptoms (such as eczema or rashes)
  • Respiratory symptoms (such as asthma)
  • Mood symptoms (such as depression)
  • Steatorrhea (fatty stools)
  • Anaemia (Iron or B12)

How do I get SIBO?

The gastrointestinal tract is a continuous muscular tube which digesting food travels along on its way to the colon. Normally, the coordinated action of the muscles of the stomach and small intestine propels the food from the stomach, through the small intestine and into the colon. This muscular action also sweeps bacteria out of the small intestine and limits the numbers of bacteria in the small intestine. However when a condition interferes with the normal activity in the small intestine this can result in SIBO. By allowing bacteria to stay longer and multiply in the small intestine the lack of normal muscular activity also may allow bacteria to spread backwards from the colon into the small intestine. Possible causes are:

Long term use of PPI’s (proton pump inhibitors eg omeprazole)

  • Batriatric surgery
  • Chronic pancreatitis
  • Blind loop syndrome (after stomach surgery)
  • Scarring from previous surgery and crohns disease.
  • Diverticuli (small pouches) of the small intestine that allow bacteria to multiply inside diverticuli.
  • Disorders of the immune system can cause bacterial overgrowth

“It is mandatory to consider SIBO in all cases of complex non-specific dyspeptic complaints (bloating, abdominal discomfort, diarrhea, abdominal pain), in motility disorders, anatomical abnormalities of the small bowel and in all malassimilation syndromes (malabsorption, maldigestion).”J.Bures et al 2010.

Getting Tested for SIBO

SIBO is measured by a breath test. This measures the hydrogen and methane gas produced by bacteria in the small intestine that has diffused into the blood, then lungs, for expiration. The gas is graphed over a transit time of 2 or 3 hours and compared to a baseline. Patients drink a sugar solution of lactulose after a 1 or 2 day preparatory diet. The diet removes much of the food that would feed the bacteria, allowing for a clear reaction to the sugar drink. The test is performed either at home with a take home kit or a breath testing machine in hospital, doctors office, or lab. It takes 1-3 hours in the morning after a 12 hour fast the night before and a special diet needs to be adhered to the day before the test.

Who should get tested?

If you have IBS symptoms that have not got better despite seeing your GP and are also suffering from a range of unexplained symptoms, acne rosacea, fibromyalgia etc it may certainly be worth ruling SIBO out as a cause for your symptoms.

Breath tests are available- these are priced  £150. – Please call me on 01323 737814 for more information.

What happens if the test is positive?

If the SIBO test is positive the best approach is antibiotic therapy taken over 7-10 days. The antibiotics will vary but this is usually enough to stop the problem and will mean you will be able to eat a normal diet again, if you have been eliminating suspect foods. Antibiotics used  can include: tetracycline, amoxicillin, metronizadole, neomycin, cephalexin, and trimethoprim-sulfamethoxazole.

There is only one study using herbal “antibiotics” for the treatment of SIBO, which used enteric coated peppermint oil (ECPO). Besides this, herbal antibiotcs have not been studied for the reduction of SIBO. The question is whether they will target the bacteria that is overgrown. However, it has been suggested that some herbal antimicrobials do not kill our beneficial bacteria, certainly a unique and desirable quality. Herbal antibiotic formulas abound in the supplement industry. These include: Garlic, Cinnamon, Oregano, Goldenseal, and Barberry.

What about special diets?

Patients who come to me with suspected SIBO issues are already on severely restricted diets – avoiding wheat, gluten, dairy, lactose, large amounts of carbohydrate and all manner of different variations of elimination diets. It is advisable to eradicate SIBO quickly and get back to eating as normally as possible rather than staying on restricted diets long term which may lead to different health issues. It is commonplace for patients to think they have multiple food intolerances and lists of foods they cannot eat when in fact it may be only a few foods and the problem they are suffering from is SIBO not from the food itself. Often people with SIBO tell me it does not matter what they eat – even a glass of water can make them feel bloated. This should ring alarm bells, if it’s not the food there is something going on in the gut. Time to get tested. There are a few diets that can help symptoms of SIBO and IBS as well. These include the Specific Carbohydrate Diet and Low FODmap diet which I will be discussing in the next issue as well as the GAPS diet which has found huge popularity recently.

For more details on tests and consultations visit or call Kate Arnold on 01323 737814 for more details.


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