Most people don't get the fiber they need from their diet and reach for fiber supplements instead. With so many products on the market, it can be hard to choose the best fiber supplements.
Fiber supplements can't replace dietary fiber, so it's best if you get fiber from food. But if you find that impossible, look for supplements that have undergone rigorous testing and that are right for your health goals. Some types of supplements are best suited for lowering your cholesterol, while others are best if you're looking to relieve constipation.
Fiber supplements are convenient, but don’t provide the same benefits as fiber from food. When choosing a supplement, understand your goals for taking fiber therapy, and which options have undergone rigorous clinical testing. Psyllium and inulin are two types of fiber.
Dietary Fiber and Recommended Intake
The average adult woman needs 25 grams of fiber per day and the average male needs 38 grams, according to the Academy of Nutrition and Dietetics. Only 5 percent of people get these recommended amounts, however, as per a paper published in the Journal of the American Association of Nurse Practitioners in April 2017.
There's no question that you need fiber for a healthy body, but the fiber you get from supplements is often not comparable to that which is intact and intrinsic to whole foods. Fiber is only found in plant foods. You get extra fiber from a diet high in produce, especially if you eat the skins and peels of fruits and vegetables. Beans, lentils, nuts, seeds and whole grains are good sources, too. When a food is heavily processed, its natural fiber content is often stripped away.
The Academy of Nutrition and Dietetics notes that fiber supplements may not give you some of the same benefits offered by dietary fiber, such as increased feelings of fullness. Optimal fiber intake is a good gauge of your overall diet quality. When you increase your fiber intake with food, you also get other nutritional benefits, such as added vitamins, minerals and antioxidants. For some people, however, fiber supplements are a necessity.
Types of Fiber
Fiber comes in soluble and insoluble forms. Most supplements come exclusively from one source, and usually consist of one type or the other.
Soluble fiber slows down digestion, helping to regulate blood sugar levels and possibly reducing LDL cholesterol, the bad kind of cholesterol. Natural sources of soluble fiber include oatmeal, oranges, carrots and barley.
Insoluble fiber bulks up your stool, so it moves more readily through your intestines and relieves constipation. It can keep your intestines healthy too, preventing colon cancer. Find insoluble fiber in foods such as dark green leafy vegetables, wheat bran, nuts or seeds.
The Journal of the American Association of Nurse Practitioners paper notes that it's important to understand the role played by the type of fiber supplement that you take. If your goal is to support metabolic health and reduce cholesterol, aim for a soluble fiber supplement; if you're needing a supplement to provide a laxative effect, go for insoluble types.
Best Fiber Supplement: Inulin
Inulin is what's known as a prebiotic fiber. It causes favorable changes to your colon's bacterial population, thereby aiding in digesting, in production of appetite hormones and in nutrient absorption. Inulin naturally occurs in asparagus, onions, leeks, wheat, garlic, chicory, oats, soybeans and Jerusalem artichokes, according to a comprehensive paper published in Current Developments in Nutrition in March 2018.
A 40-person study published in Food and Nutrition Research in July 2017 showed that supplementation with inulin fiber (16 grams per day for eight days) resulted in fewer hunger sensations and higher ratings of satisfaction and fullness at meals. The group in the study who took the fiber supplement ate 21 percent fewer calories at lunch, compared to those who did not take the supplement, suggesting a positive effect for weight management.
Best Fiber Supplement: Psyllium
Psyllium comes from the seed husks of the plantago ovata plant. It's mostly soluble fiber, but contains some insoluble fiber. It provides both blood sugar and cholesterol moderating benefits, and can help with the flow of stool through your intestines.
The paper in the Journal of the American Association of Nurse Practitioners showed that psyllium is effective for improving levels of fasting blood glucose and insulin. It also lowers LDL cholesterol levels and helps induce weight loss in people with metabolic syndrome.
Psyllium is also an effective stool softener, especially compared to methylcellulose — a treated wood pulp found in some fiber supplements , which the American College of Gastroenterology says it has insufficient data to recommend as a constipation treatment. Psyllium is also superior to wheat dextrin, which can actually be constipating, explains a March 2015 evidence-based paper published in Nutrition Today.
Medical Considerations When Adding Fiber
If you're on any prescription medications, check with your doctor before adding a fiber supplement. Fiber supplements can interfere with the absorption of certain medications, including drugs that treat thyroid issues, diabetes and high cholesterol. You may need to take fiber supplements separately from other medications to help prevent interactions.
Whether you successfully introduce more fiber into your diet, or add fiber pills or fiber powder, do so gradually. Too much fiber too soon can make you bloated and gassy. The Academy of Nutrition and Dietetics recommends you also include plenty of fluid because the addition of new fiber requires water to process it — if you don't take enough fluids with your added fiber intake, you may experience nausea or constipation.
- Academy of Nutrition and Dietetics: "Easy Ways to Boost Fiber in Your Daily Diet"
- Journal of the American Association of Nurse Practitioners: "Fiber Supplements and Clinically Proven Health Benefits: How to Recognize and Recommend an Effective Fiber Therapy"
- Nutrition Today: "Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 1"
- Nutrition Today: "Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 2"
- Current Developments in Nutrition: "Health Effects and Sources of Prebiotic Dietary Fiber"
- Food and Nutrition Research: "Acute Fiber Supplementation With Inulin-type Fructans Curbs Appetite Sensations: A Randomized, Double-Blind, Placebo-Controlled Study"
- Today's Dietitian: "Entering the World of Prebiotics"
- Fiber Choice: "Fiber Choice Tablets"
- Metamucil: "How Metamucil Works in Your Body"
- Cleveland Clinic: "Improving Your Health With Fiber"
- Harvard Health Publishing: "Will a Fiber Supplement Interfere With My Medications?"