The Fiber of Your Life

​A common suggestion for improving IBS symptoms is to simply eat more fiber. But fiber can be a complicated matter, and simply eating more of it won't necessarily improve IBS symptoms and could, for some people, make symptoms worse. 

Although incorporating more high-fiber foods into your diet may help reduce the constipation or diarrhea associated with IBS, the type of fiber you eat can make all the difference. That's because the body responds to soluble and insoluble fiber differently, and each type can helpful or harmful depending on the type of IBS you have, the IBS symptoms you're experiencing at the time, and the quantity of fiber you consume.

Soluble fiber dissolves in water, becoming a thick gel that readily ferments. It attracts water and removes excess fluid, which is why it can be especially helpful for people with diarrhea-predominant IBS. Because it slows transit time, foods high in soluble fiber can make us feel fuller faster and longer, preventing us from overeating, which is something that can trigger IBS symtpoms.

Examples of fruits and vegetables that are rich in soluble fiber include blueberries, carrots, cucumbers, oranges, and strawberries. Oats and oat bran, flaxseeds, and psyllium husks are good sources as well. Legumes (beans, lentils, and peas) are also rich in soluble fiber. However, they're also high in FODMAPs, so it's important to limit portion size and stick to lower-FODMAP types, such as canned lentils and chickpeas, until you know whether you can tolerate small servings of other varieties. Including reasonable amounts of foods high in insoluble fiber may improve stool consistency, but large quantities should be avoided, as they may exacerbate symptoms.

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Fiber supplements, such as psyllium husks, can be rich sources of soluble fiber. Try a small dose initially to see whether this type of fiber agrees with you and helps your symptoms. But remember that when you get the bulk of your fiber through whole foods, rather than supplements, you'll reap the nutritional benefits of the fruits and vegetables along with the fiber.

Insoluble fiber doesn't dissolve in water and doesn't ferment, but it does tend to be more difficult to digest than soluble fiber. Insoluble fiber is found in the "tough" matter of whole grains (such as wheat bran and corn bran), nuts, and many fruits and vegetables, especially the stalks, skins, and seeds. It adds bulk to the stool and appears to help food pass more quickly through the stomach and intestines, which can aid constipation. However, many foods that are high in insoluble fiber are also high in FODMAPs. Consequently, getting enough of this type of fiber on a low-FODMAP diet can be challenging. Good sources that are low in FODMAPs are broccoli, cabbage, collard greens, grapes, kale, and root vegetables (especially the skin of potatoes).

For optimum digestive and overall health, it's important to obtain both sufficient insoluble and soluble fiber. Dietary fiber is found only in plants foods, not meat or animal products. Fortunately, most plant foods contain both types of fiber in differing amounts, which is why having as much variety in your diet as possible is desirable. 

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Here are a few ways you can increase the fiber in your diet:

Breakfast: Have rolled oats (oatmeal), quinoa porridge, or a mixed-grain cooked cereal that contains low-FODMAP grains, such as oats, amaranth, and sorghum. Add a tablespoon of rolled oats to a smoothie, which has the added benefit of making the smoothie thicker. Make a Creamy Chocolate Breakfast Shake that includes flaxseeds, Strawberry Chia Seed Smoothie, or chia seed pudding (see "Dessert," below). Top cooked cereal with berries, enjoy a bowl of mixed low-FODMAP fruits, or have a banana with a tablespoon or two of peanut butter. Sprinkle low-FODMAP vegan yogurt with rolled oats or low-FODMAP granola. Try Almond and Pumpkin Seed Quinoa Breakfast Brittle.

Snack: Banana; orange; small handful of walnuts, hemp seeds, pumpkin seeds, or sunflower seeds; or a cup of popcorn.

Lunch: Make a sandwich with whole-grain sourdough spelt bread, whole-grain sourdough wheat bread, or a low-FODMAP gluten-free whole-grain bread. Alternatively, use large romaine lettuce leaves or raw or blanched collard leaves instead of bread. Have a salad topped with 1/4 cup of canned chickpeas, well rinsed, or make one of the high-protein nut or bean spreads from Low-FODMAP and Vegan to top your salad or use in a sandwich.

Snack: Banana; orange; small handful of walnuts, hemp seeds, pumpkin seeds, or sunflower seeds; or a cup of popcorn.

Dinner: Include a wide variety of vegetables, especially dark leafy greens and root vegetables. Broccoli, carrots, collard greens, eggplant, green beans, kale, potatoes, turnips, spaghetti squash, sweet potatoes, yellow summer squash, and zucchini are all great to have on a low-FODMAP vegan diet. Center your meal around these foods as well as whole grains, such as brown rice, millet, polenta, and quinoa. Include a salad with leafy greens and crisp raw veggies, such as shredded carrots, sliced radishes, diced cucumbers, and colorful bell pepper strips.

Dessert: Try making a chia seed pudding. Chia seeds are packed with protein, vitamins, minerals, and omega-3 fats, as well as fiber. Some people with IBS report that chia seeds trigger or exacerbate their symptoms even though the seeds are low in FODMAPs. If you can tolerate chia seeds, give them a try in Maple Walnut Chia Seed Pudding, Vanilla Chia Seed Pudding, Almond Joy Chia Pudding, Coconut Pumpkin Chia Pudding, or Chocolate and Raspberry Chia Pudding. 

What are some of your favorite ways to amp up the fiber in your low-FODMAP vegan diet? We'd love to hear your thoughts! Post them in the comment section below.

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