Most people are familiar with fiber, and know that it is part of a healthy diet. However, for those with gastrointestinal issues, like IBD, fiber is something that we may try to avoid as it can irritate our already inflamed intestinal lining. Having said this, many people assume fiber is all the same, and while you would be correct in that all fiber is carbohydrate and all slows digestion, there are actually several types. Each type reacts differently in digestion, and there are some sources of fiber that I have found personally to be ‘safe’ even with IBD.
You may say, well then there are two types of fiber; soluble and insoluble. This is true, and each of the types of fiber do fit into one of these categories, but there’s a lot more to fiber than just soluble and insoluble. Let’s start by defining each of these and seeing how they differ. Soluble fiber can be dissolved in water, forms a gel-like substance, and binds with fatty acids to help remove LDL (bad cholesterol). Insoluble fiber cannot dissolve in water and passes through the digestive tract mostly intact. And while there are actually more than seven types of fiber, I have included the seven most relevant and popular.
- Cellulose- This type of fiber is insoluble and acts as ‘nature’s laxative’. This type of fiber can aid in avoiding constipation but could cause the latter in gastro patients. It is heavily found in whole grains, whole wheat, seeds, brown rice, and produce skins. As an avid SCD follower, all of these things are not allowed with the exception of some seeds. Cellulose can aid in digestive irritability in IBD, and one I avoid in bulk.
- Inulin- This fiber is soluble and may even increase good gut bacteria and improve immune function. It is also a type of fructan and is found primarily in beets and onions, both of which interestingly enough are allowed on SCD. If you find you can tolerate these vegetables, inulin is the way to go to help out your gut’s good bacteria.
- Lignin- This is an insoluble fiber that helps heart health. However, it should be avoided if you have gluten intolerance or celiac disease and is found primarily in flax and rye. These are an SCD no-go as they are multi-chain carbohydrates and can be harder on the digestive tract than other fibers.
- Beta Glucan- This fiber helps lower LDL, reduces the risk of type 2 diabetes, and coronary artery disease. It also helps aid in fullness and lowers blood sugar levels. It is soluble and found in oats, barley, soy, peas, berries, oranges, bananas, apples, and carrots. While oats, barley, and soy aren’t allowed on SCD and should be used with caution in those with celiac, the rest are and I have had great success with them.
- Pectin- This fiber is soluble, although a few are insoluble. And found naturally in fruits, berries, and seeds. Pectin is also commonly extracted from citrus peel and other plants to boost fiber in processed foods. It has been found to help lower cholesterol and slow digestion. I have personally done well with fruit and berries, but usually avoid seeds. I also recommend avoiding it in processed food, and honestly processed foods altogether.
- Psyllium- This fiber is most often found in supplements, fiber drinks, and added to processed foods. It is soluble and most often extracted from the seeds and husks of the Plantago Ovata plant. It helps alleviate constipation and helps lower LDL. However, I have found this type of fiber to be a huge irritant with IBD, and I try to avoid it.
- Resistant Starch- Last but not least we have this soluble fiber that helps control blood sugar, increases fullness, and may reduce the risk of diabetes. This fiber is found in unripe bananas, oatmeal, potatoes, and grains. All of these are strictly prohibited on SCD and now I understand why! Resistant starches are the toughest on the digestive system and ones I personally try to avoid at all costs.
Now that we know the major types of fiber, we can then further categorize them not just by solubility, but by fermentability and viscosity. Fermentable fibers include pectin, beta-glucan, and inulin. Viscous fibers include beta-glucans and pectin, like fermentable fibers, but also include psyllium. I do want to mention that everyone is different, and I am sharing what has worked for me. I am also in no way a doctor or am telling you to cut out any particular type of fiber. You know your body best! I hope that this sheds light on an often-difficult topic for those with IBD, and gives you more information to make informed decisions on what fibers work for you.
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