IBS & Fiber
Fiber is an essential part of a healthy diet. However, for those with irritable bowel syndrome (IBS), fiber can get a little complicated. The amount and type of fiber someone with IBS consumes can change the outcome of their bowels and symptoms. If you are following a low FODMAP approach to manage IBS, unfortunately, this is also low in fiber. At the end of the day, getting fiber in that doesn't cause bowel distress can be hard for those with IBS. You’ll hear me say this again and again, IBS is individualized. Everyone is different and it's always important to see what works for you!
What is Fiber?
Dietary fiber is a non-digestible carbohydrate that comes from plants. Since it can’t be digested and isn't broken down like other foods, it stays mostly intact while going through your digestive system (this is not a bad thing)! The dietary reference intake or DRI recommends 25-38g of fiber per day for adults. Fiber can be found in fruits, vegetables, nuts, seeds, whole grains, and legumes. There are two types of fiber, insoluble and soluble. Insoluble fiber can’t dissolve in water and will simply pass through your body bulking up your stool and speeding up digestion. Soluble fiber can dissolve in water and forms a gel-like substance which slows digestion. Each is important in providing health benefits including:
Promoting healthy bowel movements
Increasing satiety (feeling full)
Controlling blood sugar levels
Feeding gut bacteria
Lowering cholesterol levels
What is the challenge with fiber in IBS?
The biggest hurdle with IBS is the fermentability of fiber. Meaning it’s quickly broken down by our gut bacteria which produces gas resulting in abdominal bloating and pain. Some examples are inulin, pectin, fructans, and galactooligosaccharides (GOS). You might recognize some of those as high FODMAP carbohydrates. While this happens for everyone, those with IBS can find these symptoms exacerbated. The tricky part is soluble fiber tends to be more fermentable but most foods have both soluble and insoluble fiber.
Take a look at some great low FODMAP yet FIBER-RICH foods. Try and incorporate these in your meals and snacks!
SupPlements
Another way to increase your fiber intake is through supplements! Some days you may need an extra boost and this can be an easy way to do it. There are many fiber supplements out there, so how do you choose? You want to find a supplement with fiber that won’t cause a lot of gas. For those with IBS, psyllium fiber is well-researched and proven to be among the favorites for fiber supplements. Psyllium fiber does not cause excess gas and can help those, especially those with IBS-C (IBS- constipation), find relief.
Summary
Fiber is an important pillar in maintaining good general health, especially for those with IBS. As you try to incorporate low FODMAP fiber-rich foods and supplements into your diet, I recommend you do this slowly. Gradually get yourself to your daily fiber goal and give your body a chance to get used to having more fiber day to day. Always remember to consult a registered dietitian before initiating any changes to your IBS management, including the use of supplements.
References:
El-Salhy, Magdy, et al. "Dietary Fiber in Irritable Bowel Syndrome (Review)." International Journal of Molecular Medicine, vol. 40, no. 3, 2017, pp. 607-613, https://doi.org/10.3892/ijmm.2017.3072. Accessed Jun. 2023.