Here’s What You Need to Know About Small Intestinal Bacterial Overgrowth (SIBO)

Here’s What You Need to Know About Small Intestinal Bacterial Overgrowth (SIBO)


1 July 2019


Bacteria play an essential role in your overall gut health and digestive system, however, an excess of bacteria - specifically in the small intestine - can lead to chronic stomach discomfort and other digestion-related issues. Read on to learn more about SIBO, how to diagnose it and steps to treating it.

Small intestinal bacterial overgrowth, also known as SIBO, is a condition that causes chronic bloating, diarrhoea, abdominal cramps and many other digestive issues. SIBO occurs when there is too much gut bacteria, or microbiota, living in the small intestine. This bacteria usually stays in the large intestine, where it belongs, but in some cases, bacteria can travel up to the small intestine resulting in bloating, gas and general stomach discomfort. 

What Causes SIBO?

Simply put, SIBO is the result of too much bacteria in the wrong part of the digestive system. Bacteria are crucial in healthy digestion, as they feed on undigested carbohydrates (also known as prebiotics) to help to release vital nutrients as well as gas. 

Ideally, this process occurs in the large intestine, which has the room to allow for the fermentation process to happen without gut discomfort. However, when bacteria move to the small intestine, the result can be increased gas production, resulting in the uncomfortable symptoms of SIBO. 

Additionally, the small intestine is where the main absorption of nutrients is done. Only the leftovers – the fibres your body can’t break down (prebiotics) – travel down to the colon (the large intestine) to be digested by bacteria. When these bacteria make a home in the small intestine, they end up eating the nutrients that would normally go directly to your cells, which interferes with food absorption.

There are various potential causes of SIBO, and each case should be considered individually. Infections, food poisoning and health conditions such as celiac disease can prevent the normal function that pushes gut bacteria from the small intestine to the large intestine from happening, leading to an overgrowth in the small intestine.

In some cases, medications (like the ones used to treat acid reflux, for example) can also have a detrimental impact on the harmony of the gut, as they work by suppressing stomach acid. This acid is crucial for keeping the bacteria levels in the intestines balanced; when diminished, gut bacteria are able to grow in undesirable parts of the digestive system - the small intestine. 

Additionally, antibiotics can contribute to SIBO as well. Whilst antibiotics are used to kill off bacteria, the problem is that they eliminate good bacteria, too, which we require for healthy digestion and absorption of our food’s nutrients. Regular and sustained use of antibiotics can cause an imbalance in gut bacteria, increasing the likelihood of developing SIBO. 

Common SIBO-Related Complications

SIBO is notoriously hard to diagnose as it mimics the symptoms of other digestive issues like irritable bowel syndrome. And oftentimes, many people never even seek medical attention regarding their SIBO symptoms. If you’re experiencing the SIBO symptoms we’ve mentioned for a prolonged period, it’s best to consult a medical physician. If left untreated, SIBO can lead to malnutrition due to the lack of vital nutrients being absorbed from your food. 

Some medical professionals also believe excess activity in the small intestine can damage the intestinal lining and lead to “leaky gut syndrome.” This means that undigested food particles, as well as toxins, that would otherwise pass through and be excreted, can slip through the gut lining and enter the bloodstream. This can potentially trigger autoimmune responses like autoimmune thyroiditis (Hashimoto’s), skin conditions such as rosacea, and chronic diseases like diabetes. More research is certainly needed in this field, so it’s important not to jump to any conclusions if you suspect you’re experiencing SIBO symptoms. Go see your doctor for further medical advice. 

How Will a Doctor Diagnose SIBO? 

A doctor will likely perform a physical examination, as well as ordering blood, faecal or other tests. Breath tests are commonly used to diagnose SIBO as well. Some tests can be performed at home, by ordering a kit. Alternatively, you can ask your doctor to order one and perform the test in their office.

It’s important to note that despite the wide use of breath tests, the results are not always reliable. The tests seem to generate many false-positives leading to some people who suffer from gastroenteritis misdiagnosed due to the slow emptying of the stomach.

A more invasive - but arguably more accurate - test for diagnosing SIBO is a test called "jejunal aspiration." This procedure involves an endoscopy procedure in which a sample of fluid is taken from the small intestine. The sample is then cultured and evaluated for the presence of bacteria. Jejunal aspiration is not generally used, due to the fact it is currently very expensive, and time-consuming. And while it’s generally considered as safe, it still carries more risks than a breath test. 

How to Treat SIBO


The important first step upon the diagnosis of SIBO is to remove any overgrown bacteria. Prescribed antibiotics include ciprofloxacin, metronidazole and rifaximin. In addition to decreasing the bacteria in the gut, it’s also important to address the underlying issues that cause SIBO in the first place.

However, as previously mentioned, sustained usage of antibiotics is going to further cause damage to the gut, so it is important to take a targeted antibiotic. Other holistic healthcare practitioners may recommend herbal antibiotics, as they tend to do less damage to the intestinal tract. Common herbal antibiotics recommended for SIBO include oregano, goldenseal and garlic.

Elimination Diets

Your doctor may recommend an elimination diet to determine the foods that may be causing your SIBO flareups. During an elimination diet, your doctor will have you remove a large variety of foods like dairy, gluten, sugar, caffeine, etc. from your diet for a period of time before slowly reintroducing these food items and tracking your symptoms.

One elimination diet that is commonly recommended as a solution for the treatment of SIBO is the low-FODMAP diet. Fermentable Oligo- Di- Monosaccharides and Polyols (FODMAPS) are types of carbohydrates that some people have difficulty digesting, causing symptoms such as bloating, pain and constipation. Reducing or eliminating FODMAP-containing foods can greatly reduce these symptoms for a period of time. However, it’s important to note that a low-FODMAP diet is only a short-term solution and will not eliminate the root cause of SIBO.  

Lifestyle Adjustments

Many people find it beneficial to decrease the volume of food they consume at each meal; choosing to eat smaller, more frequent meals. This helps to prevent an excess of undigested food left in the gut at any one time.

Whilst SIBO is treatable, it can return. It is important to address the underlying cause of SIBO, such as Crohn’s disease, but in some cases, it may be difficult to determine what the cause is. 

Try not to give up hope if you suffer from these chronic symptoms. Work with your doctor or holistic health practitioner - or both - to find a solution and work on a long-term plan that will decrease the likelihood of SIBO in the future. 

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