Health Benefits of Fiber
Fiber plays an important role in our health. Fiber regulates digestion and bowel movements, helps you feel fuller for longer and may help balance your blood sugar. Some types of fiber can be considered a prebiotic, and work with your gut microbiota to promote gut health and diversity. Fiber may even play a role in reducing the risk of developing certain conditions like cardiovascular disease, stroke, certain types of cancer, and type 2 diabetes [1].
The recommended intake for fiber is 38 grams for men under 50 years of age, and 25 grams for women under 50 years of age [2]. Dietary fiber has been consistently linked to benefits relating to the prevention and management of various diseases and reducing the risk of mortality. Most of us get fiber from food sources and supplements. Despite this, adults worldwide are typically not getting enough fiber; under 20g per day. [3].
Don’t go reaching for a canister of Metamucil just yet, though— while supplements are convenient, they don’t replace the benefits of getting your daily fiber needs through whole food sources. If you’re interested in increasing the amount of fiber in your diet, it’s sometimes hard to know the types and amounts of fiber to add to your diet. Here’s an overview of what fiber is, what fiber does, and practical ways of increasing your fiber intake.
What is Fiber?
Fiber is a plant-based nutrient that is found in plant-based foods like vegetables, fruit, whole grains, legumes, nuts, and seeds. Fiber is also available in supplement form— but more on that in a bit.
Fiber is typically harder to come by in packaged and processed foods. An example of this would be refined grains. Food companies remove all or most of the fiber from the grain to provide a finer texture and longer shelf life. Choosing whole grain products such as bread can be tricky as the label and color of the product can be misleading. To tell if the product is made mostly with whole grains, look at the nutrition label. The first ingredient listed should contain the words “whole grain”.
With that in mind, certain types of fiber— like beta-glucans, fructans, and wheat dextrin—can be found in sources that aren’t whole foods. You can check the ingredients of the product to see if a fiber is listed or check the nutrition label to see if there is an adequate amount of fiber for your dietary needs. If you’re not sure of your dietary needs, it might be time to see a Registered Dietitian Nutritionist!
While fiber is available in supplement form, fiber sourced from whole foods is your best bet for reaping the benefits. When you get fiber from whole food sources, you are also getting vitamins, minerals, and phytochemicals (antioxidants) in addition to fiber.
How Does Fiber Work?
Normally, enzymes in your body help you absorb nutrients and digest the food that you eat as it travels through your digestive system. Because we don’t have the enzymes to break down fiber, it stays relatively intact as it moves through your digestive system. As fiber travels through your body, it plays an important role in your health.
Fiber can help balance our blood sugars, lowers cholesterol, keep us feeling full for longer periods, and promotes healthy bowel movements. Some types of fiber even feed our gut microbiota!
Whole foods— especially the plant-based foods that are associated with fiber— also can help create a healthy gut microbiota. Eating a wide range of whole foods is a great way to promote gut microbial diversity, which is connected to additional benefits.
What Are the Different Types of Fiber?
Fiber can be put into two categories: soluble and insoluble [4]. Most foods containing fiber have a mixture of soluble and insoluble fibers. Across these two categories, there are many types of fiber.
There is a shift of focus in the world of nutrition away from the category of fiber (soluble vs. insoluble) to a focus on the way that different types of fiber have a different effect on the body. Here are some of the most common types of fiber, where they come from, and how they can keep you healthy.
Three Fibers You Should Know About
Inulin
Inulin is a soluble fiber that is found in many plant-based foods. It’s considered a prebiotic fiber, which means that it can work with your gut microbiota to improve your gut health and diversity. The blood-sugar regulating properties are great for everyone, especially people with diabetes, insulin resistance, and other metabolic disorders. Sources: Jerusalem artichokes, chicory, onions, bananas, leeks, and asparagus are all great sources of inulin. Inulin is even used as a fat alternative in cakes and other baked goods![5].
Cellulose
Cellulose is an insoluble fiber that can help you move food more quickly through your system. Cellulose helps make up plant cell walls and is typically found in higher amounts on the skin of plants rather than the flesh. Insoluble fibers, like cellulose may help relieve constipation. [6] Sources: Cellulose-rich foods include legumes like adzuki beans, sweet corn, cooked Brussel sprouts, and celery.
Beta-Glucans
Beta-glucans are soluble fibers that can help slow down food as it reaches the digestive tract, aiding in feelings of fullness and blood sugar regulation. Sources: Beta-Glucans can be found in cereal grains, barley, yeast, oats, and certain types of mushrooms[7].
How To Add More Fiber To Your Diet
Despite all of the benefits linked to fiber, most Americans are still falling short of the recommended intake.
The best way to increase fiber intake? Go slowly! A drastic increase in consumption of fiber might give you uncomfortable gastrointestinal side effects, so slow and steady wins the race when incorporating fiber into your diet.
Consider adding 1 serving of fiber-rich whole foods into your day for a week, and then increasing your intake to two servings a day for the next week. This could look like adding in fruit with your afternoon snack for week one, and a cup of cooked vegetables with dinner along with your fruit for your afternoon snack for week two.
Don’t forget to hydrate! Drinking plenty of water while increasing your fiber intake helps fiber do its job.
Working with a Registered Dietitian Nutritionist is one of the best ways to ensure that you are going to get enough fiber to enjoy the potential health benefits, but not so much that you will experience any gastrointestinal distress.
In the meantime, here are some great sources of fiber that you can use to slowly boost your fiber intake:
- 1 large pear – 7 grams
- 1/2 c cooked oatmeal – 2 grams
- 1/4 c baked beans 3.5 grams
- 1 oz walnuts (14 halves) – 1.9 grams
- 1/2 medium avocado – 5 grams
- 1 slice of multi-grain bread – 3 grams
- 1 cup asparagus – 2.5 grams
Do You Need More Fiber in Your Diet?
Fiber may play a role when it comes to treating or preventing gastrointestinal issues and symptoms. Studies related to the management and prevention of gastrointestinal disorders consistently determine that fiber has benefits for GI health.
Generally, whole foods such as whole grains, legumes, vegetables, and fruits are the sources of fiber that are most frequently connected to GI benefits[8]. Eating too much fiber can trigger flare-ups or worsen symptoms of gastrointestinal issues.
If you have GI issues and symptoms, working with a Registered Dietitian Nutritionist is one of the best ways to determine how much fiber you want to consume, and where that fiber should be sourced from. They can look at your symptoms, the foods you are eating, and your health goals to help you determine what types and amounts of fiber may best support your treatment plans.
References
Gill, S.K., Rossi, M., Bajka, B. et al. Dietary fibre in gastrointestinal health and disease. Nat Rev Gastroenterol Hepatol 18, 101–116 (2021). https://doi.org/10.1038/s41575-020-00375-4 https://www.dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials/food-sources-select-nutrients/food-0
Gill, S.K., Rossi, M., Bajka, B. et al. Dietary fibre in gastrointestinal health and disease. Nat Rev Gastroenterol Hepatol 18, 101–116 (2021). https://doi.org/10.1038/s41575-020-00375-4 https://medlineplus.gov/ency/article/002136.htm
Waqas Ahmed & Summer Rashid (2017): Functional and therapeutic potential of inulin: A comprehensive review, Critical Reviews in Food Science and Nutrition, DOI: 10.1080/10408398.2017.1355775
Gill, S.K., Rossi, M., Bajka, B. et al. Dietary fibre in gastrointestinal health and disease. Nat Rev Gastroenterol Hepatol 18, 101–116 (2021). https://doi.org/10.1038/s41575-020-00375-4
Rahar, Sandeep et al. “Preparation, characterization, and biological properties of β-glucans.” Journal of advanced pharmaceutical technology & research vol. 2,2 (2011): 94-103. doi:10.4103/2231-4040.82953
Thompson, E Gregory, et al. “Following a Low-Fiber Diet.” UPMC, https://www.upmc.com/health-library/article?hwid=abo1009
