Small Intestinal Bacterial Overgrowth
SIBO stands for small intestinal bacterial overgrowth and is the most common cause of irritable bowel syndrome (IBS). It occurs when bacteria normally present in the large intestine is found in large amounts in the small intestines. It’s the location of the bacteria that is problematic rather than the bacteria itself. The small intestines should only be home to very small numbers of bacteria but the large intestines need the large numbers to help complete digestion. The small intestine should only have 100,000 bacteria per ¼ teaspoon of content whereas the large intestine has as many as 20 billion bacteria per ¼ teaspoon of content.
What’s the problem with these bacteria being in the small intestine?
The bacteria will fight for all carbohydrate and sugar sources to feed themselves. They rob us of our food and nutrients and cause it to ferment. This fermentation produces the hydrogen and/or methane gas. Humans don’t produce these gases, they are only produced by the bacteria. These excess gases cause the bloating, burping, flatulence and pain. The type of gas produced can also mean your symptoms tend more to constipation or to diarrhoea.
Both hydrogen and methane also cause damage to the microvilli that line our intestines. This causes leaky gut or increased intestinal permeability. Your gut when working properly acts as a filter, letting the nutrients in while keeping the toxins out. When the gut becomes ‘leaky’ it allows toxins and larger, undigested food particles to get through. This can cause symptoms like joint pain, headaches or skin breakouts depending on your individual areas of susceptibility.
The small intestine can also have its motility damaged by SIBO. The cleansing wave or migrating motor complex (MMC) is a muscular contraction that moves content along at regular intervals throughout the day and is affected by SIBO and no longer works properly. This MMC is also impaired by stress and eating too often.
Symptoms of SIBO:
Bloating and abdominal distention
Excess gas (flatulence and/or burping)
Cramping, abdominal pain or discomfort of the abdomen
Constipation and/or diarrhoea (or alternating)
Fibre often causes symptoms to worsen
Indigestion & nausea
Fatigue
How common is SIBO?
The presence of small intestinal bacterial overgrowth is a very common. It has been estimated that up to 80% or more people who suffer from irritable bowel syndrome (IBS) also have this issue. The prevalence being unknown among healthy individuals. Doctors assume that it's Often under-diagnosed because mild cases may be symptomless while moderate ones feature many non specific symptoms which overlap other conditions.
SIBO sufferers may also suffer at least one of these symptoms:
GERD / acid reflux
Headaches / migraines
Nausea
Abdominal pain
Fat Malabsorption
Poor absorption of nutrients
Food intolerances / food sensitivities
Leaky gut
Nutritional Deficiencies
Depression or mood issues
Obesity
Fatigue
Hormonal imbalance
Joint pain
Skin issues (eczema, breakouts, rosacea)
Brain fog / concentration issues
From this list you’ll see that the symptoms affect more than just our digestive system, they can affect just about any organ. If you have small intestinal bacterial overgrowth you’ll notice a worsening of symptoms when you eat sugary and starchy foods like bread, pasta, potatoes etc. The longer SIBO has been present the more likely you are to become intolerant to more and more foods for example gluten containing foods, dairy and fructose in fruit.
Small Intestinal Bacterial Overgrowth (SIBO) has been associated with several health conditions.
These include:
- Irritable Bowel Syndrome (IBS): A significant percentage of individuals with IBS have been found to have SIBO, suggesting a connection between these two conditions.
- Inflammatory Bowel Diseases (IBD): These include conditions like Crohn's disease and ulcerative colitis. While the relationship between IBD and SIBO is complex, the changes in gut motility and the use of certain medications for IBD may contribute to the development of SIBO.
- Coeliac Disease: People with coeliac disease, especially those who do not respond to a gluten-free diet, are more likely to have SIBO.
- Diabetes Mellitus (particularly Type 2): Diabetic neuropathy can affect the nerves of the gut, causing delayed gut transit and predisposing to SIBO.
- Gastroparesis: This is a condition in which the stomach takes too long to empty its contents. Delayed gastric emptying can create an environment conducive to bacterial overgrowth.
- Chronic Pancreatitis: This condition can lead to malabsorption, which in turn can predispose to small intestinal bacterial overgrowth.
- Scleroderma (and Other Connective Tissue Disorders): These conditions can affect gut motility and lead to bacterial overgrowth.
- Hypochlorhydria: Conditions that result in reduced stomach acid (hypochlorhydria) or taking acid-suppressing medications (like proton pump inhibitors) can increase the risk of SIBO.
- Previous Intestinal Surgery (or Structural Abnormalities in the Gut): Any condition or surgery that affects the normal anatomy or motility of the gut can predispose to small intestinal bacterial overgrowth.
Keep in mind that while there are associations between these conditions and SIBO, having one of these conditions does not necessarily mean you will develop small intestinal bacterial overgrowth. It's also important to note that this list is not exhaustive and SIBO can be associated with other health conditions not mentioned here.
What causes SIBO?
A single cause of Small Intestinal Bacterial Overgrowth hasn’t been identified, but there are some known triggers and contributing factors. For many it’s a combination of factors. These are:
- A bout of gastroenteritis often occurred around the time the symptoms start
- Certain medications such as antibiotics, the pill, narcotics and prolonged use of proton pump inhibitors or antacid can be contributing factors
- Chronic stress which lowers stomach acid and interferes with migrating motor complex (MMC)
- Surgery such as appendicitis, hysterectomy or any surgery in the abdominal area that can cause adhesions
- Digestive disorders such as coeliac disease, ulcerative colitis and Crohn's disease increase the risk of SIBO
- Underlying conditions such as hypothyroidism and diabetes or poor blood sugar management
- A typical diet high in processed foods, refined flours and excess sugar
- Alcohol and even moderate alcohol consumption have been linked to SIBO (defined as 1 drink per day for women and 2 drinks per day for men)
- Glyphosate, a commonly used herbicide, acts like a low dose antibiotic, so antibiotic exposure in food is relevant
- Hiatal hernia & poor stomach function and low stomach acid (hypochlorhydria)
- H.pylori infection which may reducde stomach acid levels
- Poor methylation and gallbladder function
- Gastroparesis which causes dysmotility
- Gastric bypass surgery
- Structural issues like small bowel diverticulosis, small bowel obstructions or small bowel abdominal adhesions
- Ileocecal valve dysfunction
Is SIBO contagious?
There is no evidence that exposure to any single microorganism increases the risk for developing SIBO. Rather, it occurs due to a complex interplay among many different factors and cannot be passed on between individuals; unlike some other bacterial infections.
What foods trigger SIBO symptoms?
While foods aren’t the original cause of small intestinal bacterial overgrowth, certain foods do encourage the overgrowth of  bacteria in the small intestine. If you’re feeding them their favourite foods, they're going to grow more, and that will trigger more of your SIBO symptoms. You can also help reduce the overgrowth by starving the problematic bacteria of their favourite foods. This strategy has led to a number of proposed SIBO diet plans. The diets vary, and so do individual results. These include:
- High FODMAP foods
- Sugar alcohols
- Wheat/gluten
- Lactose
- Fermentable oligosaccharides
SIBO Testing - the best way to discover if you have SIBO
There is a simple, non-invasive breath test now available to identify if you have SIBO. There's either a lactulose breath test or glucose breath test that measures the hydrogen and methane output in a single breath. These samples are taken every 20 minutes for 3 hours and the results will tell us if you have SIBO and approximately where in the small intestines it’s present and which gas is being produced to influence your symptoms. This test is conducted in your own home after a one day preparation diet. See my SIBO Testing page for more information.
There are no blood tests for SIBO but blood results play an important role in identifying vitamin and mineral deficiencies that can lead to malnutrition. There may be a risk of developing vitamin B12 deficiency that can be checked. Thyroid issues can also be tested for.
SIBO Treatment
My 7 step process to restore your gut health was developed to address SIBO as the most common cause of IBS.
Step 1 - Stop putting fuel on the fire and remove dietary triggers with either an elimination diet or elemental diet
Step 2 - Testing where necessary to confirm it's SIBO, where the overgrowth occurs and which gas is being produced
Step 3 - Use the correct antimicrobial herbs to treat your SIBO (specific to your results and situation)
Step 4 - Address stress and lifestyle factors that influence your symptoms
Step 5 - Heal up leaky gut, reduce inflammation and reintroduce foods
Step 6 - Rebalance your microbiome and reduce risk factors for SIBO relapse
Step 7 - Get professional support and guidance so you follow the right steps in the right order
To further understand my 7-step process to restore your gut health see my Gut Fix Program.
If you’d like to find out more about the testing and treatment options for SIBO and IBS or other digestive symptoms then please book in for a free Gut Fix strategy session so I can go over your options.
Or simply call 1300 16 75 72 and leave a message if we are busy so someone can call you back as soon as free.
For further information on treating SIBO see my SIBO Treatment page. For further information on functional medicine tests see my Lab Tests page.