What Kind of Fiber Is Good for SIBO? The Low-FODMAP Guide

December 8, 2025 •

4 min read

Over 70 million Americans may struggle with digestive issues like IBS and SIBO. Navigating dietary changes is key for Small Intestinal Bacterial Overgrowth (SIBO), and a common concern is knowing what kind of fiber is good for SIBO without exacerbating symptoms like bloating and gas. The right fiber can actually be a powerful tool for recovery, but the wrong type can cause significant discomfort.

Quick Summary

Managing SIBO requires careful fiber selection. Low-FODMAP, low-fermentable fibers like Partially Hydrolyzed Guar Gum (PHGG), psyllium, and certain cooked vegetables are generally well-tolerated and can support gut motility and beneficial bacteria. Highly fermentable, high-FODMAP fibers from sources like wheat, onions, and legumes should be avoided to prevent feeding bacterial overgrowth and worsening symptoms.

Key Points

Choose Low-FODMAP Fibers: Opt for fibers that are low in fermentable carbohydrates (FODMAPs) to avoid feeding the bacteria responsible for SIBO symptoms.
Prioritize Partially Hydrolyzed Guar Gum (PHGG): PHGG is a well-tolerated, low-FODMAP, soluble fiber that has been shown to improve the effectiveness of antibiotic treatment for SIBO.
Introduce Psyllium Husk Carefully: Psyllium is a useful, bulk-forming soluble fiber, but individual tolerance varies, so it should be introduced slowly and in small amounts.
Favor Cooked Vegetables: The fiber in cooked, low-FODMAP vegetables like carrots, zucchini, and spinach is easier to digest and less likely to cause symptoms than raw vegetables.
Avoid High-FODMAP Fibers: Steer clear of high-FODMAP sources like inulin, chicory root, wheat bran, and legumes, which are highly fermentable and can trigger significant discomfort.
Start Slow with All Fiber: When adding any new fiber source, start with a small amount and monitor your body's reaction, especially for seeds and supplement powders.
Work with a Healthcare Provider: Personalized guidance from a doctor or dietitian is crucial for navigating a SIBO diet and determining the best fiber strategy for your specific condition.

Navigating Fiber with SIBO: A Delicate Balance

For individuals with Small Intestinal Bacterial Overgrowth (SIBO), dietary fiber presents a complex challenge. While fiber is a crucial component of a healthy diet, certain types of highly fermentable fibers can feed the bacterial overgrowth in the small intestine, leading to exacerbated symptoms like bloating, gas, and abdominal pain. The key is to differentiate between fibers that are rapidly fermented and those that are slowly or minimally fermented, and to focus on low-FODMAP sources.

The Importance of Low-FODMAP Fibers for SIBO

FODMAPs are short-chain carbohydrates that are poorly absorbed and rapidly fermented by gut bacteria, making them problematic for SIBO. By focusing on low-FODMAP fibers, you can reap the benefits of fiber—like improved gut motility and bulkier stool—without providing excess fuel to the bacteria in the small intestine. This approach helps manage symptoms and allows the gut to begin to heal.

Tolerable Fiber Sources for SIBO

Not all fiber is created equal when it comes to SIBO. Here is a list of fiber sources that are generally better tolerated by individuals with SIBO:

Partially Hydrolyzed Guar Gum (PHGG): PHGG is a water-soluble, low-FODMAP fiber that ferments slowly and is well-tolerated by many SIBO patients. Research shows that combining PHGG with antibiotics like rifaximin significantly increases the eradication rate of SIBO compared to antibiotics alone.
Psyllium Husk: This soluble fiber is known for its gentle, bulk-forming effects and is often recommended for SIBO. It can help regulate bowel movements and is less likely to cause gas and bloating than more rapidly fermenting fibers.
Acacia Fiber (Gum Arabic): Similar to PHGG, acacia fiber is a slowly fermented soluble fiber that can be easier on the digestive system. It acts as a prebiotic to support beneficial bacteria in the large intestine without causing the rapid fermentation that triggers SIBO symptoms.
Cooked Vegetables: Cooking vegetables breaks down their fibrous matrix, making them easier to digest. Focus on low-FODMAP vegetables like carrots, zucchini, spinach, green beans, and potatoes.
Small Portions of Low-FODMAP Fruits: While some fruits are high in FODMAPs, you can incorporate small servings of low-FODMAP options. Kiwi fruit is a good example, as studies show it helps with constipation while being well-tolerated. Berries and citrus fruits are other safe bets.
Low-FODMAP Grains and Seeds: Quinoa, oats, and ground flaxseeds can be tolerated in moderation, especially when introduced slowly. Chia seeds are another low-FODMAP option, but should be introduced gradually to assess tolerance.

Fiber Sources to Avoid with SIBO

To prevent exacerbating symptoms, individuals with SIBO should generally avoid highly fermentable, high-FODMAP fibers. These include:

Inulin and Chicory Root: Both are rich in fructans, a type of highly fermentable FODMAP that can cause significant gas, bloating, and pain in SIBO patients. They are commonly found in fiber supplements and processed foods.
High-FODMAP Fruits and Vegetables: Apples, pears, cherries, onions, garlic, cauliflower, and asparagus are all high in FODMAPs and should be avoided or limited, especially during the initial stages of a SIBO diet.
Wheat Bran and Rye: These are high in fructans and other fermentable carbohydrates that can aggravate SIBO symptoms.
Legumes: Beans, lentils, and chickpeas contain high levels of galactans and fructans, which are poorly absorbed and heavily fermented by gut bacteria.

The Role of Fiber Supplements

For some, meeting fiber needs through food alone can be challenging during a restrictive diet. In these cases, fiber supplements can be helpful, but it is crucial to choose wisely. PHGG, known for its low fermentability, is a top recommendation. Psyllium is another option, though individual tolerance varies. It is important to start with a very small dose and increase it gradually to monitor your body's response. Always check labels to ensure supplements do not contain high-FODMAP ingredients like inulin.

Comparison of Fiber Supplements for SIBO


Feature	Partially Hydrolyzed Guar Gum (PHGG)	Psyllium Husk	Acacia Fiber	Inulin & Chicory Root
Fermentability	Very low	Moderate	Slow	Very High
Effect on Symptoms	Well-tolerated, may reduce bloating	Generally gentle, individual tolerance varies	Slowly fermented, less likely to cause gas	Often causes significant gas and bloating
FODMAP Content	Low FODMAP	Low FODMAP	Low FODMAP	High FODMAP
Benefits	Improves antibiotic efficacy, supports gut motility	Bulk-forming, regulates bowel movements	Prebiotic effects, supports beneficial bacteria	Feeds bacteria (can be beneficial for healthy guts)
Suitability for SIBO	Recommended, especially with antibiotics	Can be useful, but caution is advised	Tolerable for many, slow introduction recommended	Not recommended, likely to exacerbate symptoms

The Gut-Healing Journey

Incorporating the right fiber is just one piece of the SIBO puzzle. It's often part of a broader protocol that may include antibiotics, herbal antimicrobials, and lifestyle modifications. Working with a healthcare provider or a registered dietitian is essential to develop a personalized plan that addresses your specific needs and helps you navigate the delicate balance of reintroducing foods. A phased approach, starting with very low-FODMAP fibers and gradually increasing intake and variety, is often the most successful strategy.

By prioritizing low-fermentable and low-FODMAP fiber sources, you can support a healthier digestive system and reduce the likelihood of flare-ups, ultimately moving towards long-term gut health. Remember that individual tolerance varies, so listening to your body is a critical part of the process.

Conclusion

Navigating fiber intake with SIBO requires a strategic and informed approach. The best fibers are low-FODMAP, slow-fermenting, and well-tolerated, with Partially Hydrolyzed Guar Gum (PHGG), psyllium husk, and certain cooked vegetables being excellent choices. These options provide essential digestive support without excessively feeding the small intestinal bacteria. Conversely, high-FODMAP fibers like inulin, chicory root, and legumes should be avoided as they can trigger significant symptoms. While managing fiber can be complex, incorporating the right types can be a powerful and effective step towards healing the gut and regaining digestive comfort. Always consult a healthcare professional for guidance on the best dietary strategy for your individual needs.

Frequently Asked Questions

The best type of fiber for SIBO is a low-fermentable, low-FODMAP soluble fiber, such as Partially Hydrolyzed Guar Gum (PHGG). It provides beneficial effects without causing the rapid fermentation that exacerbates SIBO symptoms.

Psyllium husk is a soluble fiber that is often better tolerated than other fibers, but individual reactions can vary. While generally low-FODMAP, some people with SIBO might experience increased gas and bloating. It is best to start with a small dose and monitor your symptoms.

No, avoiding all fiber can be detrimental to long-term gut health. The goal is to identify and consume low-FODMAP, low-fermentable fibers while avoiding highly fermentable ones that feed bacterial overgrowth.

For SIBO, the key distinction is not simply soluble versus insoluble, but rather the fermentability of the fiber. Highly fermentable fibers (like inulin) should be avoided, while slowly fermented, low-FODMAP soluble fibers (like PHGG) are preferred.

Yes, but focus on cooked, low-FODMAP vegetables such as carrots, zucchini, and spinach. Cooking helps break down the fiber, making it easier to digest. Avoid high-FODMAP vegetables like onions, garlic, and cauliflower, especially during initial stages.

Acacia fiber is a slowly fermented, soluble fiber and can be a good option for many with SIBO. It acts as a prebiotic in the large intestine without causing the rapid fermentation in the small intestine that triggers symptoms.

PHGG is effective because it is a low-fermentable soluble fiber that supports gut motility and feeds beneficial bacteria without fueling the overgrowth in the small intestine. Clinical studies have also shown it can improve the efficacy of antibiotic treatment.

You should avoid fiber supplements that contain high-FODMAP ingredients, especially inulin and chicory root fiber. Always read the ingredients list carefully to avoid these highly fermentable additives.