Key takeaways
Soluble fiber dissolves in water and forms a gel-like substance that may help relieve diarrhea, regulate blood sugar, and lower LDL “bad” cholesterol levels.
Insoluble fiber doesn’t dissolve in water but attracts water into your stool, which may help relieve constipation and support bowel regularity.
Most plant foods contain both types of fiber in varying amounts. Eating a variety of fruits, vegetables, grains, and legumes can help you reach the daily recommendation of 22 to 34 grams, depending on your age and sex.
Dietary fiber is the part of plant-based foods that mostly passes through the digestive system without being broken down or digested. It plays a key role in supporting gut health and overall well-being.
Soluble: This fiber dissolves in water and helps form a gel-like substance in your intestines. Soluble fiber includes plant pectin and gums.
Insoluble: This fiber doesn’t dissolve in water, so it passes through the intestines undigested. It includes plant cellulose, hemicellulose, and lignin.
Most plants contain both types, but in different amounts.
Read on to learn more about the differences between soluble and insoluble fiber, which one may be best for you, and the possible risks of eating too much fiber.
This article is Day 2 of Healthline’s
7-day “Gut Check” Fiber Fix Challenge
. Follow along to discover simple ways to keep your gut healthy and boost your fiber intake by following the challenge.
Soluble fiber is often recognized for relieving
.
When soluble fiber dissolves in water in the intestines, it creates a gel-like substance that
form and bulk stools, as well as improve bowel regulation.
Soluble fiber may
reduce
and regulate blood glucose levels, thereby reducing your risk of chronic conditions like cardiovascular disease and
.
Although it doesn’t dissolve in water, insoluble fiber attracts water into your stool, making it softer and easier to pass with less strain on your bowel. This could help promote bowel health and regularity.
Some
suggests that insoluble fiber may also help support insulin sensitivity. However,
points to soluble fiber as the more effective choice for lowering blood sugar.
The table below provides a quick comparison to help you select the best type of fiber for your goals. A box with “✓✓” instead of “✓” indicates that this type of fiber is more effective for this purpose:
SolubleInsolubleDiarrhea✓Constipation✓✓Cholesterol regulation✓Appetite regulation✓✓✓Weight management✓✓✓Blood sugar management✓✓✓It’s important to remember that most plant foods contain soluble and insoluble fiber, so it’s not always possible to isolate one specific type, unless you take fiber supplements.
However, choosing specific foods can help support your goals.
Soluble fibers are
in fruits and vegetables, while insoluble fibers are found in grains and cereals. That said, plants have
of fiber.
For instance, the skin of many fruits and vegetables may be high in insoluble fibers, while the inside is usually higher in
.
It’s important to eat a wide variety of fruits, vegetables, and grains to get the benefits of both kinds of fiber.
lists the following foods as high in soluble or insoluble fibers:
Soluble fiberInsoluble fiber• apples
• pears
• citrus
• berries
• plums
• peaches
• apricots
• carrots
• broccoli
• Brussels sprouts
• sweet potatoes
• turnips
• onions
• asparagus
• beans
• lentils
• chickpeas
• oats
• barley
• rye
• chia seeds• apples and pears with skin
• raspberries
• blackberries
• grapes
• bananas
• oranges
• green beans
• cauliflower
• zucchini
• broccoli stems,
• spinach
• kale
• collards
• potatoes
• celery
• bell peppers
• whole wheat
• brown rice
• rye
• corn bran
• bulgur
• almonds
• walnuts
• flaxseeds
• chia seeds
• legumesDietary fiber is a natural and important part of a balanced diet. But it’s estimated that
in the United States don’t consume enough fiber daily.
The table below outlines the daily fiber recommendations from the
Dietary Guidelines for Americans 2020 to 2025
. The amounts are measured in grams (g) and classified by age and sex assigned at birth.
It’s important to note that the new guidelines have removed these recommendations.
Age (years)MaleFemale2 to 314 g14 g4 to 820 g17 g9 to 1325 g22 g14 to 1831 g25 g19 to 3034 g28 g31 to 5031 g25 g51 and older28 g22 gIf you’re looking to increase your daily fiber intake, consider adding more fruits, vegetables, legumes, and grains to your diet. For instance:
1 slice (32 g) of whole wheat bread has almost
of fiber
a 1/2 cup (40.5 g) of raw, uncooked oatmeal has
of fiber
1 cup of boiled black beans has
of fiber
Fiber powder and pill supplements
are also available if you’re having difficulty getting enough fiber from foods and drinks. Talk with a doctor before taking fiber supplements.
Here are some tips to keep in mind when choosing foods with dietary fiber:
Refined grains like white bread, white rice, and regular pasta are typically lower in fiber than whole grain products.
Foods with added fiber might have “chicory root” or “inulin” listed on the ingredients list.
Speak with a pediatrician before giving a child fiber supplements to ensure they’re appropriate and used correctly.
Some
suggests that eating too much fiber may cause:
excess gas
(farting)
Speak with a healthcare professional if you frequently experience these symptoms. They may be a sign of a health condition that could require medical treatment, such as
irritable bowel syndrome (IBS)
.
If you have inflammatory bowel disease (IBD) like
or
and experience a flare-up of symptoms,
temporarily may be beneficial. These may be hard to digest and could worsen symptoms.
However, it’s important to gradually reintroduce fiber into your diet when symptoms improve. Some
suggests that fiber may help keep IBD symptoms in remission.
If you want to increase your fiber intake, it’s important to increase your servings slowly over time. To see all of the benefits of eating fiber, you also need to make sure that you’re drinking enough water every day.
Both soluble and insoluble fiber have their own benefits. Soluble fiber can help improve digestion and lower blood sugar, while insoluble fiber can soften stool, making it easier to pass.
Both soluble and insoluble fiber
regular bowel movements. When it comes to supplements, psyllium (a soluble fiber) has the
for relieving constipation.
Weetabix is a cereal made from whole wheat. It contains both types of fiber, but is
in insoluble fiber.
Both soluble and insoluble fibers are important for a healthy diet. They help fight diabetes and some cancers and support cardiovascular and digestive health.
Many people in the United States don’t get enough fiber in their daily diet.
Consider eating more whole foods, such as fruits, vegetables, grains, and legumes, to increase your daily fiber intake.