4 Sneaky Signs You Might Need a Fiber Supplement, According to Dietitians

Many people are aware of the health benefits of fiber, yet Americans aren’t eating enough. On average, we get about half of the recommended daily fiber intake.

Fiber offers many health benefits, such as keeping you fuller longer by slowing down digestion, promoting regularity by adding bulk and softening the stools, and more. You may recognize that you aren’t eating enough fiber when you are constipated, feel hungry soon after eating or are running low on energy.

When you experience unpleasant symptoms associated with constipation, you may wonder if you should take a fiber supplement to up your fiber game. We talked to two registered dietitians who explained what fiber supplements are and when you should consider taking one.

Do You Need a Fiber Supplement?

There are two types of fiber, soluble and insoluble fibers—and you need both. Soluble fiber absorbs water and forms a gel in the digestive tract. Insoluble fiber doesn’t absorb water but draws water to the colon and adds bulk to the stool.

Fiber is naturally found in plant-based foods—like whole grains, beans, vegetables, fruits, nuts and seeds—but it can also be extracted from food to create dietary supplements.

Before incorporating a fiber supplement into your routine, a good first step is eating more fiber-rich foods. Second is talking to your medical provider or dietitian. Your provider can evaluate your eating pattern and fiber intake, and provide specific recommendations to ensure you are on the right track.

In general, fiber supplements are a safe and effective way to up your fiber intake, says Cheryl Mussatto, M.S., RD, owner of Eat Well to Be Well. Generally speaking, anyone who struggles to meet their fiber needs through diet alone may consider taking a fiber supplement.

4 Sneaky Signs You May Need a Fiber Supplement

1. You Experience Constipation

Having trouble passing stools without straining? While the frequency of bowel movements varies among individuals, having three or fewer bowel movements each week is considered constipation. Stools that are lumpy, hard and dry, stools that become difficult to pass, or feeling as if you haven’t fully pooped can all be signs of constipation. 

Mussatto says dietary fiber, whether from foods or supplements, adds weight and volume to stool while softening it, making it easier to pass and improving regularity. In fact, one review found that taking more than 10 grams of psyllium (found in supplements like Metamucil) per day for at least four weeks helps lessen constipation.

2. You Have Watery Stools

On the other hand, your BMs may swing toward the diarrhea side. Fiber such as psyllium can also help solidify loose, watery stools by absorbing water and increasing stool bulk.

Keep in mind that if you have an infection, such as food poisoning or an underlying GI condition, or you are unsure why your stools are watery, it is best to talk to your doctor first before starting a fiber supplement.

3. Your Cholesterol Numbers Are Not Budging

Your provider may recommend boosting your fiber intake if your LDL (“bad”) cholesterol levels are higher than normal. Fiber may improve heart health by lowering LDL cholesterol, says Lindsay Malone, M.S., RDN, an instructor in the Department of Nutrition at the School of Medicine at Case Western Reserve University. When you eat, bile helps your body digest fat from food. “If fiber is present, it binds with the cholesterol in bile. To make more bile, your body pulls circulating cholesterol to your liver and breaks it down to make more bile,” Malone explains. The result? Lower cholesterol levels. According to a meta-analysis, every 5-gram increase in soluble fiber supplementation (such as psyllium) helped lower total and LDL cholesterol by about 6 points each compared to control groups.

4. Your Blood Sugar Levels Fluctuate

If managing blood sugar levels becomes a challenge despite making changes to your diet, your provider may suggest adding a fiber supplement. Fiber slows down digestion and the absorption of glucose into the bloodstream and may help manage blood sugar levels., 

Soluble fiber may be especially good for better blood sugar balance. Some examples of soluble fiber you’d find in supplements include chicory root fiber, beta-glucans, wheat dextrin, partially hydrolyzed guar gum and inulin. Some of these fibers are found naturally in foods such as oatmeal, beans and nuts. One additional perk to soluble fiber is that it may also promote the growth of beneficial gut bacteria to improve your gut health.

What to Consider Before Starting a Fiber Supplement

You May Experience Bloating At First

Heads up: Starting on fiber supplements might give you some belly bloating and gas, says Mussatto. “When you’re starting out, go easy on the fiber supplements—small doses of about 3 to 5 grams are the way to avoid too much gas. And don’t forget to stay hydrated—plenty of fluids every day will help things move along smoothly,” she adds.

Some types of fiber are also fermentable in the gut, meaning that the gut bacteria produce gas as they feed on the fiber, leading to bloating and potential discomfort. While bloating is perfectly normal, connect with your provider first to get their recommendation for the best type of fiber supplement for you.

Your Medical History and Medications Make a Difference

If you have a history of issues like Crohn’s disease or bowel blockages, Mussatto recommends connecting with your health care team first before starting any fiber supplements.

It is also a good idea to check with your doctor or pharmacist about how fiber supplements might mix with any other medications you take. One example is if you have diabetes. “Some medications can sometimes lower your blood sugar levels, which might mean adjusting your diabetes medication or insulin,” says Mussatto.

When on a fiber supplement, Mussatto suggests taking it at least two hours apart from medications to avoid any interactions that would impact drug absorption.

How Do You Know If the Fiber Supplement Is Working?

Malone suggests paying attention to your bowel movements over two weeks by monitoring at least three days of the week. (Use two weekdays and one weekend day to get an accurate snapshot, she says.) 

You may notice that your BM habits change, with less constipation or diarrhea. If blood sugar is a concern, you may notice that you have a lower hemoglobin A1C level, which measures your average blood sugar levels over three months. If you’re watching your cholesterol levels, you may see that your total and LDL cholesterol numbers have decreased at your next blood test. 

If your symptoms haven’t improved despite eating more fiber-rich foods and taking a fiber supplement, talk to your health care provider, who can suggest a different approach.

The Bottom Line

When it comes to fiber, food really is your best bet. Fiber-rich foods pack in a variety of nutrients that supplements just don’t match. Still, fiber supplements can be part of your daily routine while eating an array of fiber-rich foods, drinking enough fluids and staying active. Before starting any fiber supplementation, connect with your health care provider first to ensure that taking extra fiber is safe and recommended for you.