SIBO, short for Small Intestine Bacterial Overgrowth, has become a hot topic in the health world, and for good reason. It's getting more attention lately, especially on social media, and that awareness is a step in the right direction. Research has shown that SIBO is widely underdiagnosed, largely because its symptoms often mimic those of other digestive disorders. But when it is correctly identified and treated, SIBO management can significantly improve gut health and overall well-being.

The Microbiome: Your Gut’s Ecosystem

The digestive tract is pretty much covered in microorganisms. Sounds terrifying, but the presence of the bacteria, viruses, and fungi actually produce enzymes that help us break down and absorb foods we wouldn't be able to do on our own, including vitamins B1, B9, B12, and K. Every individual person has a unique combination of microorganisms in their gut. This is dependent on not only what you eat, but where you live, underlying diseases and conditions, genetics, even the method of how you were delivered as an infant (i.e. vaginal birth vs. C-section)!

Your gut is also home to about 80% of your body's immune cells. The presence of the gut microbiome helps to "train" the immune system; the immune system must learn to differentiate between the microbiome and the other pathogens that pass through the digestive system, which can help the immune system identify potentially harmful organisms later on.

Short-chain fatty acids, a byproduct of the microbiome, maintain the gut barrier between the gut and the bloodstream and help to mitigate inflammation throughout the body. These short-chain fatty acids also impact the nervous system through the gut-brain axis (more to come on this soon!). Emerging research shows how the gut microbiome can impact the release of certain neurotransmitters, including serotonin, and be involved in certain mood and neurological disorders.

Understanding the gut microbiome can help us see how a disruption in this system can lead to many issues. When the microbiome is disrupted, this is called dysbiosis. It can include a deficit in healthy bacteria, an overgrowth of bacteria, or a loss of bacterial diversity.

What is Dysbiosis (and How Does it Relate to SIBO)?

When the balance of gut bacteria is disrupted—whether due to a lack of healthy bacteria, an overgrowth of harmful bacteria, or reduced diversity—it’s called dysbiosis.

Small Intestine Bacterial Overgrowth, or SIBO, is a specific type of dysbiosis. It occurs when too many bacteria (or the wrong kind) colonize the small intestine, where they aren’t meant to live in high numbers. Sometimes, bacteria from the large intestine migrate to the small intestine and cause problems.

Symptoms of SIBO

Many of the symptoms of SIBO are associated with other gut disorders and may vary in intensity depending on the severity of the overgrowth. Common complaints include:

Abdominal pain
Abdominal distension
Nausea
Bloating
Indigestion
Gas
Diarrhea
Constipation
Unintentional weight loss
Fatigue
Soft, loose, and watery stool
Mucus in stool
Stool that is thin and pencil-like
Stool that is hard and lumpy

While the symptoms of SIBO are uncomfortable in the short-term, the long-term consequences can include malabsorption, vitamin deficits, kidney stones, and osteoporosis. And because these symptoms overlap with many other gut issues, diagnosis can often be delayed.

What Causes SIBO?

There are many proposed causes for the development of overgrowth of bacteria in the gut. These can typically be divided into chemical causes and mechanical causes.

Chemical causes of SIBO include low stomach acid secretions and certain medications. Stomach acid secretions help us break down and digest food, keeping bacterial growth in check. Factors that may impact stomach acid secretions include H. pylori, prolonged use of antacids or proton pump inhibitors (PPIs), and gastric bypass surgery. Other medications that can cause an imbalance in the gut microbiome include narcotics, antibiotics, and gastric acid suppressants.

Mechanical causes of SIBO relate to a slow gut motility (meaning that food and waste move too slowly through your digestive tract). The organs of the digestive system contract and move to propel food and byproducts throughout the system (and eventually come out in the form of a bowel movement). Slow or disrupted contractions of the digestive system can allow for certain bacteria to grow beyond a normal range and for bacteria primarily found in the large intestine to grow into the small intestine. Other mechanical disruptions of the small intestine include gastroparesis, intestinal pseudo-obstructions, hypothyroidism, small bowel diverticulosis, small bowel obstructions, and abdominal adhesions.

Diagnosing and Treating SIBO

SIBO is typically diagnosed using a breath test that measures methane gas levels, a byproduct of bacteria in the gut. Other blood tests, stool tests, and imaging may also be done to rule out other digestive conditions.

Treatment depends on the type of bacteria present and the underlying cause. Physicians often start with antibiotics to reduce the initial overgrowth. Further testing may be required to identify the underlying causes of SIBO and find the best course of treatment. In some cases, changes to diet—particularly reducing sugar, starch, dairy, and certain grains—can help manage symptoms and prevent recurrence. It is important to work with your healthcare team to find what will work best for your individual gut biome.

Recovery from SIBO varies: some people feel better within a few weeks, while others may take longer. Ongoing support is key.

Where Pelvic Floor Physical Therapy Fits In

SIBO isn't just about bacteria—it also involves gut motility, or how effectively your digestive system moves food through your body. That’s where pelvic floor physical therapy can make a real difference.

A well-functioning pelvic floor supports complete bowel movements, proper abdominal pressure regulation, and coordination of the muscles involved in digestion. If your pelvic floor muscles are too tight or too weak, they can contribute to incomplete evacuation and sluggish digestion—both of which may worsen or prolong SIBO symptoms.

Working with a pelvic floor PT can help:

Improve bowel movement mechanics
Reduce abdominal tension
Enhance nervous system regulation (through breathwork and manual therapy)
Support long-term gut health

Next Steps

If you’re struggling with bloating, irregular stools, or persistent digestive discomfort, it’s worth exploring whether SIBO might be part of the puzzle. A comprehensive care approach—including medical testing, dietary support, and pelvic floor physical therapy for bowel and gut health—can help you address both the symptoms and the root causes of SIBO.

You're not alone—and there’s help available to get your gut (and your life) back on track.

Meet the team at Pelvic Health & Wellness in Whitefish Bay, WI

About Pelvic Health & Wellness

Pelvic Health & Wellness was built with you in mind. We practice whole-person, individualized pelvic floor physical therapy in a caring and safe environment. Our physical therapists specialize in treating pelvic health concerns such as pelvic floor dysfunction, bowel and gut health, pelvic pain, pelvic organ prolapse, constipation, incontinence, fertility, and various pregnancy and postpartum-related conditions.

We understand that being ready to talk about and address your pelvic floor wellness concerns comes from a place of strength. We are here to support and encourage you on your journey back to health so you can return to doing what you love! If you are ready to take the first step in reclaiming your pelvic health and wellness, don't hesitate to get in touch with us today.

What in the World is SIBO?