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What Is Small Intestinal Bacterial Overgrowth (SIBO) And How Is It Diagnosed?

According to the National Library of Medicine, roughly 12% of hospital visits are for digestive issues. Issues like IBS and IBD often overlap with small intestinal bacterial overgrowth or SIBO.

The exact prevalence of SIBO is difficult to know with certainty because of factors like misdiagnoses. Many people with intestinal issues don’t seek medical attention at all, further muddling the exact data.

What exactly is SIBO, and what makes it different from IBS? If you aren’t familiar with SIBO, you may have questions about the symptoms, causes, and treatment.

In this article, you’ll learn helpful information about small intestinal bacterial overgrowth. Read on for a guide to SIBO.

What Is Small Intestinal Bacterial Overgrowth?

Small intestinal bacterial overgrowth occurs when a patient’s small intestine is home to an unusually high population of bacteria. To maintain a healthy bacterial population, your body has natural antibiotic and probiotic defenses in place.

If your body’s defense against overgrowth doesn’t work properly, the concentration of bacteria gets too high. This is when a patient develops SIBO.

Although there is a lack of clarity on some specifics regarding SIBO, we do have many general guidelines. There is a higher percentage of SIBO diagnoses among older populations. SIBO is also more prevalent in women, though the exact reason for this remains unclear.

SIBO Symptoms

Early indicators of SIBO closely resemble irritable bowel syndrome. While “good bacteria” are essential to gut health, too many in the wrong place (small instead of large intestine) can lead to digestive issues.

It is common for patients to experience digestive problems that get worse without medical treatment. Specifically, the following symptoms are common among SIBO patients:

An “overfull” or bloated feeling
Diarrhea or constipation
Lack of certain vitamins, most often B12, with no cause
Weight loss
Stomach pain

In extreme cases, SIBO can lead to complications like kidney stones, osteoporosis, and poor fat absorption. When your body can’t absorb fats, you can also develop vitamin deficiencies.

The reason for SIBO symptoms has to do with how the small intestine normally functions. When you eat food, your small intestine mixes the food with digestive juices and helps your body absorb it.

However, when too many bacteria populate the small intestine, they can interfere with your ability to absorb nutrients. The bacteria also consume food themselves, the byproduct of which can cause bowel problems like bloating and gas.

SIBO Causes

SIBO can occur in patients for a variety of reasons. Most often, SIBO is a comorbidity of another condition, such as:

Crohn’s disease
Radiation enteritis
Scleroderma
Celiac disease
Diabetes
Other conditions that affect digestion

Alternatively, the cause of SIBO can be a physical property of the patient’s small intestine. If the small intestine develops growths like scar tissue or other structural problems, it can disrupt the flow of the small intestine.

Sometimes, SIBO occurs as a complication of certain surgeries. Gastrectomies and gastric bypass surgery, for example, can lead to SIBO in some cases.

Other things that affect the flora in the gut can also lead to SIBO. A low-fiber diet and smoking are examples of factors that can affect gut flora.

SIBO Treatment Options

The most direct way to reduce the population of bacteria in the small intestine is with antibiotics. The antibiotic medication kills bacteria, returning the population to a normal level.

However, antibiotics won’t treat the root cause of bacteria overgrowth, meaning the condition may return after treatment. Bacteria can also become resistant to antibiotics over time, making treatment ineffective.

A controversial treatment for SIBO is the opposite of antibiotics: probiotics. Rather than eliminating the overgrowth of bacteria, the idea behind probiotics is to promote the growth of good bacteria to balance the population.

Data on probiotics as a treatment for SIBO is inconclusive. Some studies support it as a treatment, while others show it may worsen the condition.

A relatively new treatment option for SIBO is fecal microbiota transplants. With this treatment, the patient has the gut flora of a healthy donor transplanted into their body.

FMT is also controversial as a treatment because of the lack of proven data.

To create a lasting reduction in bacterial overgrowth, it’s essential to determine the root cause. A doctor may examine the patients eating habits and routine, as well as medical and family history.

Altering your diet is a way to naturally correct SIBO. Although it isn’t a cure, it can reduce symptoms.

SIBO Diet Plans

Diet plans vary in effectiveness from person to person. What works for one patient may worsen another’s condition.

Reducing lactose and eating more B12-rich foods can ease the symptoms of SIBO. A popular diet for aiding SIBO is the low FODMAP diet, which reduces the consumption of:

Fermentable oligosaccharides
Disaccharides
Monosaccharides
Polyols

The body doesn’t break these substances down before excretion, so bacteria can feed on them if they build up in the gut. Certain kinds of carbohydrates are high FODMAP foods.

The type and amount of food you should eat on a low FODMAP diet depends on your body type. For this reason, you should consult a dietician before making any drastic dietary changes.

How Experts Diagnose SIBO

Although there isn’t one universally accepted method of diagnosing SIBO, doctors have narrowed down a few methods. Sometimes, a doctor will use a small intestine aspirate and fluid culture.

This test involves inserting a narrow flexible tube into the intestine via the throat to obtain a sample. The sample is then tested for bacteria levels.

Another less invasive test for SIBO is to have the patient drink a sugar solution and test the breath for methane, hydrogen, and sometimes hydrogen sulfide. Other tests include blood and stool testing.

Improve Your Health Instead of Just Symptoms

If you have symptoms of IBS or IBD, it may be an indication of small intestinal bacterial overgrowth. You may experience indigestion, bloating, diarrhea, or constipation.

Your doctor will evaluate your diet and medical history before testing for SIBO. Upon diagnosis, common treatment options include antibiotics and diet plans.

If you’re concerned about your symptoms, visit Fairbanks Family Wellness. Our naturopathic doctors don’t just treat symptoms with medication; we promote wellness by finding the root cause of health problems.