Commonly found in fruits, vegetables, grains, and legumes, fiber is an indigestible carbohydrate that's necessary for the movement of food through the digestive system. While supplements shouldn't be a replacement for all those fiber-rich foods, some people with irritable bowel syndrome (a.k.a. IBS) may find them to be helpful. In order to find the best fiber supplements for IBS, I got in touch with Niket Sonpal, M.D., a NYC-based internist and gastroenterologist, and Joel Totoro, R.D., the sports science director at Thorne. According to both experts, when determining which fiber supplement is best for you, there are a handful of different factors to consider.
"When asked about fiber supplements and IBS, the answer, unfortunately, is — it depends," Totoro tells Mic. "IBS is a multifactorial condition, and we need to consider the type of IBS (C, D, or M) if we are in an active flare-up or recovery mode." (IBS-C is the most common and means you primarily experience constipation; IBS-D manifests mostly as diarrhea; and IBS-M or IBS-A, involves both overly solid and overly loose stools.)
That said, the type of IBS you have could impact what kind of fiber you're looking for, and there are two types: either soluble or insoluble. Soluble fibers dissolve in water to create a gel-like consistency, which "slows down digestion and helps decrease diarrhea," according to Dr. Sonpal. Insoluble fibers, on the other hand, do not dissolve, so they create "a bulking function that [...] promotes the movement of digested food through the body," Totoro explains.
Both specialists primarily recommend soluble fiber over insoluble fiber. Dr. Sonpal writes, "Insoluble fiber is poorly fermented," and as a result, it "may make your pain and abdominal bloating worse." Totoro does note, however, that while insoluble fiber "tends to be a bit harsher and more likely to trigger symptoms," it may "move things along more quickly, which can be desirable for those managing IBS-C."
According to Totoro, the ideal fiber supplement will feature multiple soluble fiber sources, like guar gum, pectin, and psyllium. He adds that it's also important to take it slow and not massively up your fiber intake all at once. You may want to aim for supplements with less than 10 grams of total fiber to start. Of course, everyone is different, so what works for one person might not work for another — and it's always a good idea to speak with your doctor to make sure a supplement is the right fit for you.
With Totoro's and Dr. Sonpal's guidance in mind, these are some of the highest-reviewed supplements on Amazon for those with all types of IBS.
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1. The gastro-recommended one
- Dietary fiber per serving: 2 grams
This Heather's Tummy Fiber Organic Acacia Senegal is a popular choice on Amazon, with more than 1,000 five-star reviews, and it also comes reommended by Dr. Sonpal. "This prebiotic [fiber] is good for those experiencing diarrhea and constipation as a symptom of IBS," Dr. Sonpal says, adding that it "helps with good bacteria growth in the gut and may reduce gas by slowing colonic fermentation." This supplement uses 100% acacia senegal powder (that's USDA-certified organic) to move things along at a healthy pace. It's a powder supplement that dissolves into room-temperature water, but you can also add it to moist foods.
One reviewer says: "I have severe IBS-C. I have tried many different things natural and prescriptions but nothing helped to ease it for any long term period. So I researched and found this and checked with my GI doctor and he approved. It has been almost 2 years now and I haven't had to suffer from IBS-C or IBS-D. I also stopped bloating, feeling full and distended all the time."
2. The fan favorite
- Dietary fiber per serving: 1.1 grams
"Longer structured soluble fibers, such as psyllium, produce gas at a slower pace, which allows the body to absorb and eliminate these gasses without symptoms," says Tortoro.
It makes sense, then, that this psyllium husk supplement is a top-seller for soluble fiber capsules. It has a 4.6-star rating overall after more than 8,000 reviews, with multiple fans calling it a "game-changer" for IBS. It's also less than $20 for 500 capsules, despite the fact that it's non-GMO, vegan, keto-friendly, and made without common allergens. You can also opt for a 200-capsule bottle.
One reviewer says: "These capsules are amazing. I had done some research into ways to help my IBS and I cannot believe how much it has impacted my life. Like everyone else has said in their comments, it really changed the game for me!"
3. The concentrated one
- Dietary fiber per serving: 7 grams
Because of its prebiotic blend, this Thorne's FiberMend helps balance the GI's gut flora while generally being gentle enough for those with IBS. And it has the most dietary fiber per serving out of the options on this list, with 7 grams. It's free from common allergens like gluten, eggs, tree nuts, soy, yeast, and fish. This unflavored powder fiber supplement has hundreds of fans on Amazon, and it's also Totoro's top choice due to its inclusion of guar gum and pectin.
One reviewer says: "Excellent product. This fiber does a great job for me. No bloating or uncomfortable side effects. Gentle on my system."
4. The one with soluble & insoluble fiber
- Dietary fiber per serving: 6 grams
As previously mentioned, soluble fiber is often easier to tolerate — but insoluble fiber may help those with IBS-C. Garden of Life's Super Seed supplement contains both soluble and insoluble fiber, and they come from whole-food sources like sprouted seeds, grains, and legumes. You're also getting omega-3 fats, probiotics, and enzymes in every serving, and since it's a flavorless powder that mixes well into smoothies and recipes, it's easy to incorporate into your daily routine. Last but not least, this brand is certified vegan, USDA-organic, non-GMO, and gluten-free.
One reviewer says: "I developed IBS-C after never having a problem with constipation in my entire life. Tried so many pills, laxatives, nothing helped. Until this fiber. [...] I also love that it's a blend of natural fiber sources and probiotics."