What are Symptoms of SIBO?

What are Symptoms of SIBO?

One of the most frustrating things are "vague" symptoms without a clear cause. Joint pain, brain fog, insomnia, and fatigue just to name a few. SIBO symptoms can easily wreck havoc on your life. SIBO occurs many times with seemingly no underlying condition.

The good news is you can deal with small intestinal bacterial overgrowth (SIBO) fairly easily once you can pinpoint that you have it.

How common is Small Intestinal Bacterial Overgrowth (SIBO)?

Some studies have found that up to 80% of people with irritable bowel syndrome (IBS) have SIBO. It's also estimated that 5-15% of people have undiagnosed small bowel bacterial overgrowth. These people may suffer from a number of vague symptoms which are hard for a doctor to pinpoint the cause. This makes it hard to treat SIBO.

What causes SIBO?

Our understanding of Small intestinal bacterial overgrowth SIBO is still limited. We are discovering more causes each time we study small intestinal bacterial overgrowth.

SIBO can be caused by abdominal surgery, diabetes mellitus, prolonged use of proton pump inhibitors, or parasite infection such as H. Pylori. The underlying cause of SIBO in these situations is low gastric acid in the GI tract.

Parasite infections produce toxins and can disrupt a healthy gut. Parasite produce gases when they die off as well.

There are also a host of other issues that can cause SIBO symptoms.

Small intestine dysmotility when waste is slow to move through small intestine before it goes to the large intestine. This may cause large intestinal bacteria to move up into the small intestine. When this happens a number of gastrointestinal symptoms are common. This disruption is what leads to the nutritional deficiencies so common in irritable bowel syndrome.

Irritable Bowel Syndrome and Inflammatory bowel disease

IBD is a known to be a cause of SIBO. Crohn's disease is a known cause of SIBO. Crohn's disease can lead to issues with intestinal permeability. Small bowel diverticulosis is another common irritable bowel disease that can cause SIBO symptoms. Celiac disease is now starting to be linked to SIBO as well. Celiac disease is linked to intolerance of gluten and creates abnormal motility (movement) through the digestive system. This motility disorder damages your intestinal walls.

Overuse of medications

Certain medications can upset the balance of gut flora. These include antibiotic therapy, proton pump inhibitors, and other illegal drugs. Antibiotic therapy may increase gastrointestinal symptoms by killing off good gut bacteria. Proton pump inhibitors and drugs create low stomach acid in the body.

Low stomach acid is a common condition where SIBO occurs.

How does SIBO affect my body?

Small intestinal bacterial overgrowth can lead to persistent symptoms as well as vitamin and mineral deficiencies. The reason is the digestive tract is vital to our overall health. When the digestive tract has trouble creating bile acids or loses the ability to absorb nutrients, the health problems spiral.

There are common symptoms - both physical and Psychological of SIBO

Physical symptoms of Small intestinal bacterial overgrowth:

  • Abdominal pain and bloating

  • Nausea

  • An uncomfortable feeling of fullness after eating

  • Diarrhea

  • Unintentional weight loss

  • Malnutrition

  • Excess gas

  • Joint pain

  • Vitamin deficiencies

  • Mineral deficiencies

  • Difficulty absorbing fat soluble vitamins

  • Inability to digest lactose

  • Low ability to digest fats

Psychological symptoms of small intestinal bacterial overgrowth:

  • Brain Fog

  • Insomnia

  • Fatigue

  • Nervous system issues

Small intestinal bacterial overgrowth is challenging to pinpoint because the symptoms cascade once it starts. When SIBO symptoms flare up, bile salts are broken down by the intestine because there are too many bacteria. Low bile salts leads to the difficulty to digest fats and absorbing fat soluble vitamins.

The bacterial overgrowth then disrupts the normal gut flora. Problems with the normal balance of gut flora lead to the host of other problems like vitamin and mineral deficiencies. Poor absorption of vitamins and minerals are an underlying cause of many of the psychological symptoms associated with SIBO.

This is why some patients with SIBO reported severe psychological disturbances.

Tests for Determining If You Have SIBO

SIBO is many times under-diagnosed unless patients have a clear medical history indicating a problem. Some doctors do not believe in SIBO, instead saying that these problems "are in your head".

Many times SIBO is diagnosed by a Naturopath Doctor familiar with digestive tract issues.

Let's talk about some of the testing:

Glucose vs. lactulose breath testing

Two of the common SIBO testing mechanisms are a glucose breath test and a lactulose breath test. This can also be called a hydrogen breath test or a methane - hydrogen breath test.

Glucose breath testing is more accurate than a lactulose breath test and leads to fewer false positives. Lactulose breath testing is more common.

For both tests, you blow into tubes at intervals to get breath samples.

The Hydrogen breath test is also effective in diagnosing lactose, fructose, or sucrose intolerance.

A bacterial culture may be taken from both the hydrogen breath testing as well. In rare cases a bacterial culture may be taken using an endoscopy. An endoscopy bacterial culture is less common due to its invasive nature.

Limitations to Testing

One of the biggest issues with intestinal bacterial overgrowth tests are they are not always accurate. This is one of the reasons treating SIBO is difficult. Blood tests are notoriously inaccurate. This is why SIBO treatment is normally delayed: The symptoms are mistaken for other causes.

Doctors have started to realize SIBO testing is inaccurate. More and more doctors are treating SIBO as the underlying cause to vague health issues.



The digestive system and gut bacteria are complex. Our GI tract is responsible to absorb nutrients and get toxins out of our body. When the GI tract doesn't provide the nutritional support our body needs, we can see a cascade of symptoms.

Many of the conditions are caused by poor absorption which create nutritional deficiencies: from vitamin deficiency to fat malabsorption.

The underlying condition for low levels of gastric acid and excess gas many times is SIBO. One of the biggest issues with small intestinal bacterial overgrowth (SIBO) symptoms are they are difficult to diagnose.

A breath test isn't always accurate, which many times delays SIBO treatment. In the future, our hope more doctors recognize the prevalence of bacterial overgrowth.

With studies showing that 80% of people who have inflammatory bowel disease have SIBO, it's worth developing more protocols to deal with SIBO symptoms.

Starting on a SIBO diet such as FODMAP is effective at reducing SIBO symptoms.