Beyond bloating: what SIBO is and what you can do about it

Chronic bloating, gas, abdominal discomfort, constipation, or diarrhea can be incredibly frustrating — especially when symptoms seem to show up after almost every meal. If you’ve been told “everything looks normal” but you still don’t feel normal, there may be more going on beneath the surface. That chronic bloating could be SIBO.

Small Intestinal Bacterial Overgrowth (SIBO) occurs when bacteria that normally reside in the large intestine begin to overgrow in the small intestine. Normally, your small intestine has a very low bacterial count – most of your gut microorganisms live in the large intestine.  When too many organisms set up shop in the small intestine, they can interfere with digestion and absorption and can damage the tissue itself. Considering that your small intestine is where the majority of your gut hormones (that influence your whole body) are produced and where most of the nutrients are absorbed, this can cause some major issues.

Could your bloating be SIBO? Learn the symptoms, causes, treatment options and ways to reduce recurrence. #saslife
Share on X

What Exactly Is SIBO?

SIBO typically develops when natural protections — like stomach acid, digestive enzymes, bile acids, or gut motility — aren’t working properly. This leads to premature fermentation of food, increased gas production, bloating, abdominal pain (mostly from bloating), nausea, heartburn/GERD, and changes in stool (diarrhea, constipation). Since SIBO symptoms are usually triggered by eating, a classic sign is waking up feeling okay and getting progressively more bloated as the day goes on.

Side note: Small Intestinal Fungal Overgrowth (SIFO), while not technically a type of SIBO, can have very similar symptoms but is tested for and treated differently.

How is SIBO Diagnosed?

The best way to test for SIBO is a breath test in which you drink a sugar solution (like glucose or lactulose) and exhale into a collection device over two to three hours. The microorganisms in your GI tract will ferment the solution and produce different types of gas. The type(s) of gas that are overproduced tell you what kind of SIBO you might have.

Different types of SIBO:

Hydrogen SIBO is the most common (about 60% of cases) and is usually associated with diarrhea.

Intestinal Methanogen Overgrowth (IMO) involves methane-producing archaea, and its hallmark symptom is constipation, because methane slows motility.

Intestinal Sulfide Overproduction (ISO) tends to be the most severe (and least common) and is usually correlated with urgent watery diarrhea and other symptoms like bladder irritation and even body pain.

Who Is at Risk for SIBO?

As mentioned earlier, your body has safeguards to prevent overgrowth in the small intestine: stomach acid kills bacteria, bile and digestive enzymes have antibacterial properties, and your immune system clears out invaders. And then there's the Migrating Motor Complex (MMC) – the coordinated muscle contractions that sweep your GI tract clean during fasting.

The MMC is your number one defense against SIBO, and impaired motility is the most common cause.

Things that slow the MMC can include:

certain medications (NSAIDs, opiates, narcotics, corticosteroids, antibiotics, tricyclic antidepressants, GLP-1 agonists)

certain disease states (diabetes, hypothyroid, Ehlers-Danlos, scleroderma, Parkinson's, TBI, gastroparesis)

obstructions or adhesions from abdominal surgery, injury, or endometriosis

Other risk factors include low stomach acid, pancreatic enzymes or bile production (chronic PPI use, H2 blockers, excessive antacid use, aging, chronic stress), dysfunctional gut immunity, having other GI disorders (IBD, celiac, etc.) and food poisoning.

Common Treatment Approaches

Treating SIBO involves reducing excess bacteria in the small intestine and addressing why the overgrowth happened in the first place. You and your healthcare provider will work together to decide what treatment option is right for you.

1. Antibiotics

Xifaxan (Rifaximin) is often the first line treatment for all types of SIBO. Xifaxan is a different kind of antibiotic. It is not systemically absorbed and works mainly in the small intestine. It also has some anti-inflammatory properties. Methane‑dominant SIBO (IMO) usually pairs Xifaxan with neomycin or metronidazole to get to the methane producing archaea that are a little more stubborn.

Herbal antimicrobials like oregano oil, neem, or Allicin can work just as well as prescription antibiotics for certain people with hydrogen or methane dominant SIBO.

Treatments for sulfide overproduction are still in the works. However, pairing Xifaxan with bismuth subsalicylate has been shown to be very effective. Treatment length usually depends on how high the results were.

2. Elemental Diets

Elemental diets are basically a liquid-only formula that provides fully broken-down nutrients – amino acids, simple carbs and fats – in forms that are easily absorbed in the gut without fermentation. You are depriving the bacteria of their food source, so essentially starving out the overgrowth. This is typically done for 14 days. Studies show a success rate of 50-100%, usually depending on the type of SIBO.

This treatment option is usually saved for patients that didn’t see results with antibiotics or couldn’t tolerate the antibiotics – mainly because 14 days of a liquid only diet (that doesn’t taste very good) is not easy!

Prevention Tips: How to Reduce the Risk of SIBO Returning

Recurrence rates for SIBO are high unless you address the cause.

1. Support Gut Motility

Issues with motility are the most common reason for SIBO. So, anything you can do to increase or support the Migrating Motor Complex (MMC) will help reduce recurrence.

This might include:

Prokinetics – at bedtime

Herbal or supplement – liquid Iberogast, ginger, etc.

Or prescriptions for more serious MMC issues

Space meals 4–5 hours apart – no gum or sweetened beverages

12‑hour overnight fast

Daily movement/activity – especially in the morning (walks, stretching, etc.)

Having a warm beverage in the morning to stimulate motility

2. Support Digestion

Slow down at mealtimes, take a few deep breaths before eating, chew your food well and don’t overeat

Digestive enzymes taken with meals are sometimes necessary

Probiotics after treatment can be helpful for some

Stress management – chronic stress can impact stomach acid and motility!

Must have a daily bowel movement!

What about Diet?

Before treatment: Carbohydrates feed the bacteria, so reducing overall carb intake typically reduces symptoms. Beyond that it can be very individualized. There are more restrictive diets that might help reduce symptoms even more, like a Low FODMAP Diet. However, this kind of restriction is meant to be short-term only. Long-term restrictions shrink your microbiome diversity and can make digestive issues worse, not to mention increasing food fear, feelings of deprivation and increasing your risk of nutrient deficiencies.

During treatment: Eat a well-balanced diet with as much diversity as possible. You don’t need to stick to low carbohydrate intake while on antibiotics (unless you need to for other reasons). You want all the gut microorganisms to be out and about so the antibiotics can take care of them!

After treatment: A well-rounded, lower carbohydrate diet with as much plant diversity and fiber as tolerated is the long-term goal. You might need to start slow though. Don’t forget about the meal spacing mentioned above and the meal hygiene strategies. It can also be helpful to minimize highly processed foods and alcohol.

Start Simple

If you are having chronic GI symptoms, first make sure to talk to your healthcare provider so they can rule out more serious causes first. Then, start to reduce highly processed foods, especially highly processed carbs, fried foods, and sweet drinks (sugar or artificially sweetened). Start to focus meals around protein, non-starchy veggies, healthy fats, and nutrient-dense carbs, and drink about half your body weight in ounces of water. Just these simple steps can help to reduce symptoms. Please work with a knowledgeable dietitian/nutritionist as well rather than white knuckling it alone.

Jerk Chicken & Mango Slaw Bowls with Honey Lime Cream

Makes 4 servings
Recipe Adapted from: Crisp Tastes
PRINT RECIPE

Ingredients
4 large chicken thighs (or 6-8 smaller ones), boneless and skinless
2 Tbsp jerk seasoning
1 Tbsp olive oil
2 cups cabbage, shredded (or coleslaw mix – shredded cabbage/carrots)
1 red bell pepper, sliced
¼ cup cilantro, chopped
¼ cup mayonnaise
1 Tbsp honey
1 lime, juiced
Salt and pepper to taste
1 mango, diced

Instructions

Preheat the grill to medium-high heat.

Rub the chicken thighs with jerk seasoning and olive oil.

Grill the chicken for about 5 minutes on each side or until fully cooked.

In a large bowl, combine cabbage, red bell pepper, and cilantro.

In a separate bowl, whisk together the mayonnaise, honey, lime juice, salt, and pepper.

Pour the dressing over the slaw and toss to combine.

Once the chicken is cooked, slice it and serve it over the slaw, topped with diced mango.