Fiber, found in fruits and vegetables, nuts and seeds, and whole grains and legumes, usually helps prevent constipation. However, not everyone feels better with increased fiber, and in some cases, it can make constipation worse. There are plenty of high fiber and low-fiber options to create a balanced diet that helps you feel your best.
Constipation is the decreased frequency of bowel movements and can be caused by many different factors.
For many people, increasing fiber intake helps ease constipation, while others feel worse.
Non-fiber options may also help with constipation.
Constipation is an uncomfortable condition where you have fewer than three bowel movements during a week. In addition, stool may be dry, hard, small, and difficult to pass. Increasing fiber intake is a good solution for many people. But what kind of fiber? And how much?
Sometimes more fiber doesn’t seem to help — and can even make the situation worse. Many factors, including lifestyle, diet, medication side effects, and some health conditions, can cause constipation. Continue reading to learn what types of fiber are best and what to do if extra fiber isn’t helping.
Causes of chronic constipation
Many different things can cause constipation, and some people have constipation due to more than one factor. Some situations that can cause constipation include:
Some medications and supplements slow down the rate at which stool moves through the intestines. Other medicines can alter how much water is in your body, which makes the stool harden and become more difficult to pass. These medications include opioids, iron supplements, Parkinson’s medication, seizure medicine, and medications used for muscle spasms or depression.
When your routine changes, your bowel movements can change too. This can happen because you’re traveling, have become pregnant, have gotten older, or have made a major dietary change.
Some conditions can lead to constipation, including dehydration, a low-fiber diet, or physical inactivity. Other reasons for constipation may include diabetes, Parkinson’s disease, celiac disease, hypothyroidism, or any condition or injury that affects the nerves or digestive tract.
Types of dietary fiber
Dietary fiber often helps ease the discomfort of constipation. What is referred to as dietary fiber is carbohydrates from plant-based foods that the human body cannot digest. Food from animal sources doesn’t contain fiber; you can only get fiber from plant foods, like grains, nuts, seeds, fruits, and vegetables.
Although fiber does not offer energy (or calories), it still serves an important role for gut health maintenance. Specifically, health-promoting bacteria, called probiotics, digest fiber and rely on this fuel to help their colony numbers thrive.
The U.S. Dietary Guidelines recommend getting fourteen grams of fiber for every 1,000 calories you eat. The average amount of fiber needed for adults is 28 grams per day and your intake should be spread throughout your meals.
There are two types of fiber (soluble and insoluble), which differ by whether they dissolve in liquid or not. Most plant based foods have a combination of the two categories of fiber — both types are essential for your health.
This type of fiber dissolves in water and turns into a gel in your intestines, which helps stool pass through smoothly. Soluble fiber also slows digestion and has been found to lower the risk of heart disease. Foods highest in soluble fiber include thoroughly chewed nuts and seeds, beans, oats, barley, peas, and bran.
This type of fiber is often called roughage and does not dissolve in water. Instead, it acts like a broom to clean your intestines and help move the stool along. Insoluble fiber adds bulk to your stool, making it easier to pass. Foods high in insoluble fiber include raw fruits, vegetables, and whole grains.
Psyllium fiber is best
Last year, a group of scientists reviewed sixteen randomized controlled trials conducted on people with chronic constipation. The study looked at which types of fiber supplements were effective, reviewing wheat bran, pectin, inulin, and psyllium. This study, published in the American Journal of Clinical Nutrition, found that psyllium fiber was the most effective.
While all fiber supplements improved stool frequency and led to less straining and discomfort, psyllium fiber was the most effective. The researchers found that at least ten grams of psyllium fiber per day was adequate for easing constipation. The psyllium fiber supplements also improved stool consistency, making it softer and easier to pass. Psyllium fiber is sold over the counter in products like Metamucil.
Adding more fiber to your diet
Many different types of fiber supplements are available. However, the FDA does not regulate supplements as strictly as they regulate medications. So, if you plan to take a fiber supplement, it’s a good idea to seek out a brand checked by an independent third party for purity. Furthermore, experts recommend increasing fiber slowly to give your gut time to adjust.
If you’d like to add more fiber to your meals, increasing the amount of plant based food you eat can help. All plant foods contain fiber, but some have more than others. Examples of high-fiber foods include:
- Raspberries and blackberries
- Brussels sprouts
- Split peas
Is more fiber always better?
Many people feel better when adding more fiber to their diet, which often helps improve constipation. However, not all people feel better with more fiber, and some scientific studies have shown that increasing dietary fiber can cause more constipation, not less.
Studies show that some people actually improve their gastrointestinal health when they reduce or eliminate dietary fiber in their diet. Other studies show that increasing fiber intake does not help constipation symptoms, stool frequency, or pain during bowel movements.
An older, small study including 63 people with constipation with an unknown cause, called idiopathic constipation, broke the participants up into three groups. The groups went fiber-free for two weeks and afterward, they either resumed their regular high-fiber diet, reduced their fiber intake, or eliminated all fiber foods from their diet. The results surprised everyone: the less fiber they ate, the better they felt. Those who ate no fiber had more bowel movements, less straining, and less bloating. Although these findings are interesting, more research is needed to validate the results.
Other things to try
While increasing fiber consumption is often a good idea, you can try other non-fiber sources if you think fiber isn’t helping you stay regular. One option is to increase your magnesium intake. Several types of magnesium, including what’s commonly known as Epsom salts (magnesium sulfate), can be taken orally in supplement form to ease constipation. Talk with your doctor about starting magnesium supplementation if you find fiber doesn’t help with constipation.
The science shows that most people can improve constipation by making changes to their fiber intake. If you find that increasing the fiber in your diet doesn’t help your symptoms, speak with your doctor. Not everyone does well with increased fiber, but your healthcare team can help you find a solution.
- National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms and Causes of Constipation.
- Medline Plus. Soluble vs. insoluble fiber.
- The American Journal of Clinical Nutrition. The Effect of Fiber Supplementation on Chronic Constipation in Adults: An Updated Systematic Review and Meta-analysis of Randomized Controlled Trials.
- The American Journal of Gastroenterology. Myths and Misconceptions About Chronic Constipation.
- World Journal of Gastroenterology. Effect of dietary fiber on constipation: a meta-analysis.
Show all references
- World Journal of Gastroenterology. Stopping or reducing dietary fiber intake reduces constipation and its associated symptoms.
- Nutrients. Magnesium Oxide in Constipation.