SIBO: The Secret Contributor to Irritable Bowel Syndrome

10/12/2022 | 5 min. read

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SIBO-The Secret Contributor to Irritable Bowel Syndrome

If you have irritable bowel syndrome (IBS), you’re not alone. Cases of IBS are clearly on the rise—and so are the sales of prescription and over-the-counter drugs to treat IBS. Yet, as a naturopathic doctor I like to treat the root of the issue—not the symptoms—and that’s definitely the case with IBS.

Researchers have discovered a little-known condition called small intestinal bacterial overgrowth (SIBO) that is contributing to the symptoms and distress of IBS. And treating SIBO can often alleviate IBS, right at the source.

What is SIBO?

Your digestive tract is inhabited by many different microbes, like bacteria and yeast, most of which are housed in your large intestine. These microbes help create a microbiome, or community of organisms that are involved in many specialized functions in your body, including digestion.

Unlike your large intestine, which is literally saturated with bacteria, your small intestine should contain very few bacteria species. But this isn’t always the case. Sometimes, bacteria can invade the small intestine and proliferate there, leading to SIBO.

When SIBO develops, unwanted colonies of bacteria take hold and can damage the mucosal cells lining the small intestine walls. As a result, the small intestine can no longer effectively absorb nutrients from your food—especially fat-soluble vitamins and iron.

Plus, these unwanted bacteria can ferment improperly digested food in your small intestine—producing a number of uncomfortable symptoms associated with IBS, such as painful gas and bloating.

What Are the Symptoms of SIBO?

Symptoms of SIBO can include:

  • Bloating
  • Belching
  • Heartburn
  • Nausea
  • Abdominal pain or cramping
  • Diarrhea
  • Constipation
  • Alternating diarrhea/constipation

And the latest scientific research points to a strong association between SIBO and IBS. In fact, SIBO can be found in over half of all IBS cases, and when treated properly, can help alleviate many symptoms associated with IBS.

Diagnosing SIBO

Although research hasn’t pinpointed an exact cause of SIBO, I’ve found common links among my patients who have tested positive for this condition:

  • Long-term use of acid reflux medications, especially proton pump inhibitors
  • Long-term use of antacids
  • Long-term use of antibiotics
  • Food poisoning, with subsequent onset of IBS symptoms
  • Conditions that worsen constipation, including hypothyroidism and diabetes
  • Bowel surgeries
  • Bowel obstruction conditions, such as diverticulitis

Plus, there are often additional clues that can point to SIBO, including:

  • Unexplained anemia and/or chronically low ferritin levels
  • Malabsorption of nutrients
  • Systemic symptoms associated with leaky gut such as joint pain, fatigue, skin rashes, thyroid dysfunction, and cognitive dysfunction (i.e. foggy brain)
  • Constipation after eating vegetables
  • Worsening symptoms when taking probiotics with prebiotics
  • Improvement of symptoms after taking antibiotics

Breath Testing

If you believe you have SIBO, work with an integrative medicine practitioner to complete a SIBO breath test. Breath testing measures both hydrogen and methane—two gases that are produced by overgrowth of bacteria in your small intestine. So if the test detects an abnormal elevation of gases, you can be quite certain that your small intestine is harboring excess bacteria.

The test requires you to drink a lactulose or glucose solution after completing a one day preparatory diet. (The diet eliminates foods that would fuel the bacteria, ensuring that the test measures a reaction to the sugar solution alone.) The good news is, this test can be done in the comfort and privacy of your own home.

In fact, I recently learned about an at-home SIBO breath test that you can use over and over again to track progress with treatment. It’s called the AIRE 2 device and Food Marble is the company that makes it. You can also track what FODMAP foods lead to higher hydrogen and methane gas production. 

What Are Your SIBO Treatment Options?

Once you have a confirmed SIBO diagnosis, there are many treatment options for you to consider. These are recommendations that I have found helpful, but please work with your doctor for more specialized treatment options. For my patients, I recommend the following approach:

  1. Eliminate excess small intestine bacteria with a 2- to 4-week course of antimicrobial herbs and/or antibiotics. My preferred treatment is herbal, and I rotate a combination of herbs such as garlic, berberine-containing herbs (goldenseal, oregon grape, coptis), olive leaf, Pau D’Arco, wormwood, black walnut, and oregano oil.
  2. If patients prefer to take antibiotics, I will prescribe Xifaxan (Rifaximin) for hydrogen dominant SIBO, or Xifaxan and neomycin for methane dominant SIBO. Xifaxan is a very expensive medication, however, and insurance may not cover it. Research shows a 50% failure rate with Xifaxan, so multiple rounds are often required, particularly if the next three steps are neglected.
  3. Next, introduce (and stick to) a specific diet that restricts foods known to fuel small intestine bacteria. I highly recommend a SIBO diet developed by one of my colleagues, Dr. Allison Siebecker. Visit for complete details. Some patients prefer to follow the Low FODMAP or Specific Carbohydrate Diet (SCD). Everyone will benefit from consuming more bitter foods like arugula or dandelion greens. Bitter foods stimulate the gallbladder and help to “prime” the digestive tract. These diets are for short term use only as they restrict healthy fibers needed for proper gut function.
  4. Support your body’s natural function of sweeping bacteria through, and out of, your small intestine. This function is performed through a mechanism called the migrating motor complex (MMC), and I’ve found that certain medicines called pro-kinetic agents encourage strong MMC function. My favorite pro-kinetic agent is low-dose naltrexone (LDN) because it also has helpful anti-inflammatory benefits. Prucalopride (Motegrity) is another pharmaceutical available that is a very effective pro-kinetic agent. Other herbal pro-kinetic agents to consider are iberogast, which is a bitter herbal formula, and ginger.
  5. Finally, to help prevent the recurrence of SIBO, take specific nutrients to help nourish and fortify your gut, including hydrochloric acid (HCL) taken with meals (not indicative for everyone), bitter herbals, and pancreatic enzymes. You can also add glutamine, zinc carnosine, turmeric and colostrum for extra GI support. Probiotics can be helpful as well, but make sure to select a formula without prebiotics like FOS or inulin because prebiotics actually feed bacteria and can increase the risk of SIBO recurrence.
Dr. Drew Sinatra

Meet Dr. Drew Sinatra

Dr. Drew Sinatra is a board-certified naturopathic doctor and self-described “health detective” with a passion for promoting natural healing, wellness, and improving quality of life by addressing the root cause of illness in patients of all ages. His vibrant practice focuses on treating the whole person (mind, body, and spirit) and finding missed connections between symptoms and health issues that are often overlooked by conventional medicine.

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