The IBS & Gut Disorder Centre


How do you test for Small Intestinal Bacterial Overgrowth?

The test for SIBO is called a Hydrogen Breath test. This test is conducted at our clinic in central London or in the comfort of your own home. We can post SIBO tests all over the UK.

What does the SIBO Test measure?

The test measures two different gases Hydrogen and Methane. These gases are produced by bacteria should they exist in the small intestine.

How is the Hydrogen Breath test conducted?

The first step involves following a low-fibre diet and fasting for 14 hours. You will then need to drink a solution called Lactulose. This is a very sweet solution that tastes like sugar. Breath samples are taken every 20 minutes for the period of 3 hours. The Hydrogen breath test is non-invasive and very easy to complete. If you do this test at home we will send you a you tube video.

What is the difference between the Lactulose and Glucose Breath test?

The lactulose breath test has the advantage that the lactulose is able to travel throughout the entire small intestine. This is important as you will be able to understand if there is bacteria in the ileum (the final section of the small intestine), where SIBO sometimes occurs.

However for some people, the speed at which food moves through their intestines can be very rapid, causing Lactulose to reach the colon too quickly. This can result in a false positive result.
A false positive result may occur if you have frequent diarrhea or know that you tend to experience a faster transit time.
Lactulose can have a laxative effect on the body and can indeed increase transit time and help with constipation. This may be why some people feel better after the SIBO test.

Should I use a Glucose Breath test instead?

The problem with the glucose breath test is that is is unable to identify the growth of bacteria it in the last section of your small intestine. This means the test may produce a false negative result. We recommend that you book a consultation with a professional so we can give you our expert advice on what test to use.
(1, 3).

Does the test detect Hydrogen sulfide?
There is another gas called Hydrogen Sulfide that may also be linked with Small Intestinal Bacterial Overgrowth. Unfortunately at present this gas cannot be detected through standard SIBO tests. A SIBO test result with flat line SIBO may be linked to Hydrogen Sulfide production, particularly if you are experiencing all the symptoms of SIBO such as wind, flatulence, bloating.
If you have many of the symptoms of SIBO or you have noticed an unpleasant smell similar to sulfur, then hydrogen sulfide overgrowth might be an issue. We recommend anti-bacterials and a low-sulfur diet to help you.

What is SIBO?

Small intestinal bacterial overgrowth (SIBO) is a painful condition of the gut caused by the presence of excessive numbers of bacteria in the small intestine. The small intestine is where most of the digestion and absorption of food and nutrients happens. Unlike the colon which is part of the large intestine and proliferates with bacteria, the small intestine is normally sparsely populated by bacteria. Bacterial overgrowth can happen when bacteria move from the large intestine to the small intestine or when naturally occurring bacteria in the small intestine grow out of control.
In a healthy individual, the body will try and remove large concentrations of bacteria from the small intestine using a migrating motor complex, MMC to sweep out the bacteria.

SIBO can develop when the normal control mechanisms that keep the growth of bacteria in check are disrupted.

What are the causes of SIBO?

•Low levels of stomach acid as seen with Helicobacter pylori infection or with ageing
This is know as Achlorhydria (lack of Hydrochloric acid)- this may be due to long-term use of proton pump inhibitors,

•Use of medications that reduce stomach acid production including proton pump inhibitors such as Omeprazole as the latter may cause bacterial overgrowth in the duodenum and stomach. Proton pump inhibitors also accelerate intestinal transit- diarrhea.

• Food poisoning- Acute Gastroenteritis that may affect the MMC - motor migrating complex

• Pancreatic exocrine insufficiency, (lack of pancreatic enzymes)

•Conditions resulting in reduced gastrointestinal motility such as gastroparesis (delayed stomach emptying), irritable bowel syndrome, Crohn’s disease, coeliac disease and small bowel dysmotility

•People with a suppressed immune system

•Decrease in Bile acids- bile acids don't allow bacteria to grow

•Stress because it reduces the motility of the intestine potentially causing an overgrowth

What are the symptoms of SIBO?

The signs and symptoms of SIBO are non-specific and are similar to other digestive disorders such as irritable bowel syndrome (IBS), lactose intolerance and fructose malabsorption. Common complaints include:

•Abdominal pain and discomfort
•Excessive gas and flatulence
•Unintentional weight loss
•Inability to tolerate high fibre foods including vegetables,broccoli, beans, lentils, onions and garlic.

How can you be tested for SIBO? Hydrogen Breath Test
Because of the large amount of symptom overlap of SIBO with other gastrointestinal conditions like IBS, it is important that proper testing is done to ensure a correct diagnosis and treatment. If symptoms point to SIBO, then a breath test is usually requested. A breath test measures the concentration of hydrogen and methane in the breath. These gases are produced by bacteria from the fermentation of carbohydrates in the gut. You need to follow a special diet 24 hours before doing the test which involves drinking a sugar glucose or lactulose drink and then breathing into collection tubes. If you would like to test for SIBO, please contact our clinic- [email protected]

Is there a cure for SIBO?

In many cases, SIBO can be successfully treated by directly addressing the bacterial overgrowth. The most common first-line antibiotic prescribed is Rifaximin. The problem with antibiotics is that they are not always initially effective with one study finding that in people with SIBO-related IBS, two-thirds had to be retreated with Rifaximin, with some needing retreatment up to 5 times. This raises the very serious concern of developing bacterial antibiotic resistance.

We have successfully used herbal treatments such as oil of oregano, lemon balm, and red thyme oil, we have found these to be an effective alternative treatment for SIBO. A 2014 study found that herbal treatments were just as effective as the antibiotic rifaximin in treating SIBO. And from the same study, herbal treatments were just as effective as triple antibiotic therapy in people that did not respond to rifaximin.

These can also very important as well when treating SIBO.

What are prokinetics?
The term prokinetic means simply to promote movement and, in the context of the gastrointestinal tract. These are not be confused with laxatives. A prokinetic is useful to stimulate the MMC complex- motor migrating complex and is best taken at bed before fasting and help clear bacteria out of the small intestine.

Some examples include:
Ginger root and ginger formulas (1000 mg )
Motility activator-This is less likely to cause side-effects with patients who have acid reflux.
Pure encapsulations-MotilPro
Bio-Mi Kinetic

The Importance of Diet and SIBO
Dietary changes are also an important part of managing SIBO. Because bacteria feed on carbohydrates, then a diet that aims to reduce these can help. A low FODMAP diet is sometimes recommended to treat SIBO and which also has proven effective in treating IBS. FODMAPs are short-chain carbohydrates such as lactose, fructose, fructans (long chains of fructose molecules) and sugar alcohols that are commonly present in dairy products, grains, legumes and certain fruits and vegetables. The reduction in fermentable carbohydrates in the diet helps to starve excess bacteria of their important food source.

Following the low FODMAP diet for extended periods of time may lead to a reduction of healthy gut bacteria know as Bifidobacteria. Therefore it is important after treatment SIBO and following a low-fodmap diet to take probiotics to replenish the concentration of healthy gut bacteria (7).
The low FODMAP may also results in calcium deficiency.

The elemental diet is another option for people with SIBO. The diet supplies nutrients in an easy-to-digest form. The easier and quicker digestion and absorption of nutrients mean there is less available for bacteria to feed off. In a 2-week study of people with SIBO-related IBS trialling an elemental diet, 80 percent returned a normal lactulose breath test after 1 month.

With SIBO, different dietary changes work for different people. That is where working with an experienced nutritionist to assist in tailoring changes to your diet to manage symptoms of SIBO can be of help. Please contact us at [email protected]

The SIBO breath test (Small Intestinal Bacterial Overgrowth) is also an excellent test that is now available and is also of tremendous benefit to IBS sufferers.

How can I order a SIBO test-
If you would like to do book in SIBO test, at our clinic please contact us by [email protected]

or by phone - 0345 1297996 and we can arrange a consultation.

We recommend using a lactulose breath test or a hydrogen breath test, however we do offer glucose testing as well.

In my experience, at least 40% of patients who have IBS and have taken the SIBO test do test positive for SIBO.

There has also been a study conducted by Dr. Mark Pimentel and published in The American Journal of Gastroenterology that claims 84% of IBS patients have abnormal lactulose breath tests and were diagnosed with SIBO.

The NHS still does not routinely test for SIBO, but it is certainly worth investigating if you have been diagnosed with IBS.

How common is SIBO?

The prevalence of SIBO ranges from 30-85%.

The prevalence of SIBO in patients with coeliac disease non-responding to a gluten-free diet was as high as 50%.
In liver cirrhosis, SIBO was diagnosed in more than 50% of cases.
In a small study on elderly people (70 to 94 years old) who had lactose malabsorption, SIBO was documented in 90%.


1. Breath testing for small intestinal bacterial overgrowth: maximizing test accuracy.

2. Breath tests in the diagnosis of small intestinal bacterial overgrowth in patients with irritable bowel syndrome in comparison with quantitative upper gut aspirate culture.

3. Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy

4. Intestinal Bacterial Overgrowth
A Comprehensive Review How to Interpret Hydrogen Breath Tests Therapy Is Equivalent to Rifaximin for the Treatment of Small Intestinal Bacterial Overgrowth of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date 14-Day Elemental Diet Is Highly Effective in Normalizing the Lactulose Breath Test

7. Altered gastrointestinal microbiota in irritable bowel syndrome and its modification by diet: probiotics, prebiotics and the low FODMAP diet.
Staudacher HM1, Whelan K1.

8. The effect of ginger (Zingiber officinalis) and artichoke (Cynara cardunculus) extract supplementation on gastric motility: a pilot randomized study in healthy volunteers.
Lazzini S1, Polinelli W, Riva A, Morazzoni P, Bombardelli E.
© Victoria Tyler
The IBS & Gut Disorder Centre

0345 1297996


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