Helping You with Every Fiber of Its Being: An Exploration of Dietary Fiber
- erikasiesennop
- 6 days ago
- 4 min read
There’s often a lot of talk about fiber and how most folks don’t get enough each day, and for good reason. There are multiple reasons why fiber is important, but fiber can be tricky for most of us to have in sufficient amounts each day. All food groups are important, though we thought we’d take some time to look closer at fiber. Let’s dive in!
Types of Fiber and Their Functions
There are different types of fiber, and they have some shared as well as unique properties…
Soluble - Dissolves in water
Bile acid binding: Soluble fiber creates a gel-like substance in the stomach that binds to and helps clear bile acids (which are made in the liver from cholesterol), preventing their reabsorption.
Reduction in Blood Cholesterol: When bile acids are cleared from the body, the liver will utilize cholesterol in the blood to create new bile acids, which ultimately reduces blood levels of cholesterol.
Blood Glucose Moderation: The gel-like substance formed by soluble fiber helps slow digestion, which allows cells along the digestive tract more time to absorb glucose (and other substances) and thereby helps moderate glucose levels after meals and over the course of the day.
Improved Satiety: Because of its impact on slowing digestion, soluble fiber can help us feel fuller longer and be more satisfied after meals/snacks. Also, fermentation of soluble fiber into short-chain fatty acids (SCFAs) by gut bacteria in the large intestine promotes the release of satiety hormones.
Gut Health: The SCFAs created from fermentation of soluble fiber serves as nourishment for gut cells and can help reduce inflammation and support the intestinal barrier.
Insoluble - Does not dissolve in water
Adds bulk to stool, making it softer and helping it move through the digestive system more easily, which can reduce risk of constipation. The bulk also serves as “exercise” for your intestinal muscles, which can help keep them functioning well.
Improved Satiety: Insoluble fiber also helps satiety as it physically adds bulk to your meal which can slow digestion. Food sources of insoluble fiber are often more fibrous and require more chewing. This requires the release of saliva and gastric juices, which can support satiety signaling.
Added Fibers: Sometimes called “functional fibers”, this type is made of indigestible carbohydrates, extracted from plant sources, and added to foods or sold as supplements. Benefits of these fibers can vary, but those reported are similar to those of soluble and insoluble fiber.
Food Sources
Fiber is largely found in plant-based foods. Many fiber-containing foods have both soluble and insoluble fiber in them. The ratio varies depending on type of food, such as whether it’s a fruit, vegetable, or whole grain. Eating a variety of fiber sources can help support overall adequate fiber intake.
Soluble: oats, peas, beans, chickpeas, lentils, apples, bananas, avocados, citrus fruits, carrots, broccoli, Brussels sprouts, sweet potatoes, turnips, onions, asparagus, pears, berries, plums, peaches, apricots, barley, rye, chia seeds
Insoluble: whole grains (whole wheat, brown rice, rye, corn bran, bulgur), wheat bran, almonds, walnuts, flaxseeds, chia seeds, beans, cauliflower, green beans, potatoes, lentils, chickpeas, peas, zucchini, broccoli stems, leafy greens (spinach, kale, collards), celery, bell peppers, apples and pears with skin, raspberries, blackberries, grapes, bananas, oranges
Added or “functional” fiber: may be found on nutrition labels as psyllium, resistant starch, inulin/chicory root, methylcellulose, wheat dextrin, acacia gum, polydextrose, and cellulose. Products/fiber supplements such as Metamucil, Benefiber, FiberChoice, Citrucel, and FiberCon contain added/functional fiber.
Daily recommendation
The recommended daily intake of fiber for women is 25 grams, and 38 grams for men. Nearly 95% of us in the United States fall short of these targets!
Considerations if you’re wanting to increase fiber intake
Do so gradually: Increasing fiber too fast and/or getting too much can lead to unpleasant gastrointestinal issues, such as gas and bloating. Monitor how you feel if you’re increasing your fiber intake, and slow things down if your body is giving you signs that it’s too much too fast.
Food Sources versus Fiber Supplement?: As we’ve noted, there are many food sources of fiber, so supplements aren’t required. However, if supplements feel like a helpful way to support overall increased fiber intake for you, then this can be a beneficial option! You can always talk with a registered dietitian about your current fiber intake and they can help assess whether you could benefit from more, and brainstorming how to meet your goals via food and/or supplemental fiber.
Hydration: Water is very important as one is increasing fiber intake as it helps the fiber work effectively and reduces risk of uncomfortable side effects. Fiber absorbs water and helps bulk and soften stool, which makes it easier to pass. Too little water and too much fiber can lead to gas, bloating, harder stools, and constipation. No thank you on any of those…! A dietitian can also help you determine how to shift your water intake to support your fiber intake.
Also, for those on GLP-1 medications: Fiber and GLP-1 (glucagon-like peptide-1) work together by enhancing natural satiety and managing gastrointestinal side effects, as fiber boosts the body’s own GLP-1 release. Adequate fiber intake can also help prevent constipation that is commonly seen with GLP-1 medication use.
If you want to know more about fiber and its role in your health, reach out! We’re happy to help!
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Written by Sarita Aguirre, MS, RDN, LDN, CEDS-C
