IBS Diet & Recipes > Soluble vs. Insoluble Fiber > Insoluble Fiber
Insoluble Fiber ~ Good or Bad for Irritable Bowel Syndrome?
Both! Here's the type of fiber everyone is familiar with insoluble fiber is in bran, whole grains, raw fruits and vegetables (note the exceptions under Soluble Fiber), greens, sprouts, legumes, seeds, and nuts. In short, the healthiest foods in the world are high in insoluble fiber, and what everyone should be eating as much of as possible. Right? Well, right, except for one small problem.
Insoluble fiber, like fat, is a very powerful GI tract stimulant, and for those of us with Irritable Bowel Syndrome this can spell big trouble. Unlike fat, however, you cannot simply minimize your insoluble fiber intake, as this will leave you with a seriously unhealthy diet. It's a Catch-22, but the insoluble fiber conflict can be solved fairly easily.
Insoluble Fiber Foods Eat with Care for IBS
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One glance will tell you these insoluble fiber foods are the best (and tastiest) around, but your colon simply can't handle it if you eat them with abandon. You absolutely must eat insoluble fiber foods, and as much as safely possible, but within the IBS dietary guidelines. Treat insoluble fiber foods with suitable caution, and you'll be able to enjoy a wide variety of them, in very healthy quantities, without problem.
Eating for IBS.
In general, if a plant food (no animal products contain fiber) seems rough, stringy, has a tough skin, hull, peel, pod, or seeds, be careful, as it's likely very high in insoluble fiber. This is not a comprehensive list of insoluble fiber foods by any means but it should give you the general idea.
Whole wheat flour, whole wheat bread, whole wheat cereal
Whole grains, whole grain breads, whole grain cereals
Beans and lentils (mashed or pureed they're much safer)
Berries (blueberries, strawberries, blackberries, cranberries, etc.)
Grapes and raisins
Peaches, nectarines, apricots, and pears with skins (peeled they're
Apples (peeled they're safe)
Oranges, grapefruits, lemons, limes
Dates and prunes
Greens (spinach, lettuce, kale, mesclun, collards, arugala, watercress,
Whole peas, snow peas, snap peas, pea pods
Bell peppers (roasted and peeled they're safer)
Eggplant (peeled and seeded it's much safer)
Onions, shallots, leeks, scallions, garlic
Cabbage, bok choy, Brussels sprouts
Tomatoes (peeled and seeded, especially raw, they're much safer)
Cucumbers (again, peel and seed them and they're much safer)
Sprouts (alfalfa, sunflower, radish, etc.)
Never eat insoluble fiber alone or on an empty stomach. Always eat it with a larger quantity of soluble fiber, and you will keep your gastrocolic reflex stable.
What does this mean in practical terms? Cook some diced vegetables into a low-fat sauce for pasta, stir-fry veggies into a fried rice, or blend fresh fruit into a smoothie to drink after a breakfast bowl of oatmeal. For fruits, vegetables, and legumes in general, peeling, chopping, cooking, and pureeing them will significantly minimize the impact of their insoluble fiber.
Make soups, drinks, sauces, breads, and dips from your veggies and fruits instead of eating them whole and raw. For beans and lentils, cook and blend them into sauces, dips, soups, or spreads - their insoluble fiber is found in their outer skins and their insides are actually rich in soluble fiber. For nuts, finely grind and incorporate them into breads or cakes with white flour, which gives a safe soluble fiber base. For bran and other whole grains, eat them in small quantities following soluble fiber foods have a little whole wheat dinner roll after a big sourdough one, or mix a small amount of fat-free granola into a large bowl of cream of rice or Corn Chex cereal. For raw fruit and green salads, eat them at the end of a soluble fiber meal instead of at the beginning. For all insoluble fiber foods, start with small quantities and gradually increase your intake.
Some fruits and vegetables are particularly troublesome for IBS:
Sulfur-containing foods (garlic, onions, leeks, broccoli, cauliflower, cabbage, asparagus, and Brussels sprouts), in addition to their high amounts of insoluble fiber, also produce significant gas in the GI tract and this can trigger attacks. As with all other fruits and veggies, however, these are extremely nutritious foods with significant health benefits, so they need to be treated with caution but definitely not eliminated from your diet.
Acidic foods (citrus fruits, vinegars, and cooked tomatoes) should be treated with extra care as well, as their acidity can cause both upper and lower GI distress. Once again, follow the rules for insoluble fiber and eat these foods in smaller quantities incorporated with soluble fiber but please do eat them.
Fructose, a fruit sugar, can cause gas, bloating, and diarrhea (this is typically not true for sucrose, or plain table sugar). Honey contains fairly high amounts of fructose. Fruit juices, particularly apple and grape juice, are often sky high in fructose and even more problematic than whole fresh fruit. It's simply much easier and faster to drink a large glass of juice (and ingest a great deal of fructose) than to eat an equivalent amount of whole fruit. So treat juices as you would insoluble fiber and drink them carefully, with soluble fiber foods.
Still confused about the two different kinds of fiber? Don't worry, most folks are at first. Check the IBS Diet FAQ, and you'll likely find the answers to your questions.
While understanding the difference betweeen soluble and insoluble fiber is critical, there's another crucial component to eating safely for Irritable Bowel Syndrome. Learn about trigger foods - and why they're best eliminated from your diet altogether.
Take immediate control of your symptoms with the IBS Diet Kit.
Wondering if the Eating for IBS diet really helps? See what people have to say!
Who is Heather and where did the Eating for IBS diet come from? Read my story.
Learn IBS Trigger Foods
- IBS Safe Foods
- Soluble Vs. Insoluble Fiber
- 10 Commandments of Eating for IBS
Excerpted from Eating for IBS.
All Irritable Bowel Syndrome and IBS diet information is authored by Heather Van Vorous, copyrighted, and MAY NOT BE REPRODUCED without permission.