Dietary fiber, also known as forage, is the indigestible part of plant foods. Fiber has many health benefits, including reducing the risk of heart disease and type 2 diabetes.
Fiber is mostly found in vegetables, fruits, whole grains, and legumes. There are two types of fiber – soluble and insoluble – and both play important roles in health:
- Insoluble fiber does not dissolve in water and adds bulk to stool, preventing constipation.
- Soluble fiber absorbs water, forming a gel-like substance in the digestive system. Soluble fiber can help lower cholesterol levels and regulate blood sugar.
This article examines the different types of fiber, why they are important, and suggests healthy foods high in fiber.
Dietary fiber is an essential part of a healthy diet. It is essential for maintaining a healthy gut and reducing the risk of chronic health problems.
Most people in the United States don’t get enough fiber from their diet. By some estimates, only 5% of the population meet recommendations for adequate intake. This means that most people in the United States could obtain health benefits from increasing their daily fiber intake.
Eating fiber has many health benefits:
Protection against heart disease
Over the past few decades, several studies have examined the effect of dietary fiber on heart health, including preventing cardiovascular disease and lowering blood pressure.
The authors say that these cardiac protective effects could be due to the fact that fiber lowers total cholesterol and low density lipoprotein (LDL) cholesterol, also called “bad cholesterol,” which are a major risk for heart disease.
Better gut health
Fiber is important for keeping the gut healthy. Eating enough fiber can prevent or relieve constipation, helping wastes move smoothly through the body. It also promotes a healthy gut microbiota.
According to a 2015 study, dietary fiber increases stool bulk, helps promote bowel movement, and reduces the time that waste products spend inside the intestines.
According to a 2009 study, dietary fiber has a positive impact on gastrointestinal disorders, including:
- colorectal ulcer
- hiatal hernia
- gastroesophageal reflux disease
- diverticular disease
A 2019 study reports that fiber intake can lower a person’s risk of colorectal cancer.
Reduced risk of diabetes
Adding more fiber to the diet can also have beneficial effects on diabetes. Fiber can help slow the body’s absorption of sugar, helping to prevent spikes in blood sugar after meals.
For people wishing to lose weight, a diet high in dietary fiber can help regulate weight loss. Foods high in fiber help a person feel fuller for longer and can help people diet.
The fibers include non-starch polysaccharides, such as cellulose, dextrins, inulin, lignin, chitins, pectins, beta-glucans, waxes and oligosaccharides.
Soluble and insoluble are the two types of dietary fiber.
Most foods high in fiber contain both insoluble and soluble fiber, so people don’t have to think too much about the difference. Instead, they can focus on the overall fiber intake.
Soluble fiber dissolves in water and forms a gel-like substance in the stomach. The bacteria later break down the gel in the large intestine. Soluble fiber provides calories for the individual.
Soluble fiber offers the following benefits:
- lowering LDL cholesterol in the blood by affecting the way the body absorbs dietary fat and cholesterol
- slow down the absorption of other carbohydrates through digestion, which can help regulate blood sugar
Good sources of soluble fiber include:
Insoluble fiber does not dissolve in water and passes through the gastrointestinal tract, much of it intact. It does not provide calories.
Insoluble fiber helps build bulk in the stool, helping a person pass stool faster. It can also help prevent constipation.
Good sources of insoluble fiber include:
- whole grain foods
According to the Academy of Nutrition and Dietetics, the recommended intake of dietary fiber in a 2,000 calorie diet is:
- 25 grams (g) per day for adult females
- 38 g per day for adult men
People need less fiber after age 50 at around 21g for women and 30g for men. During pregnancy or breastfeeding, women should aim for at least 28g per day.
Learn more about the daily fiber recommendations.
People who are allergic to foods high in fiber may find it difficult to get enough fiber. They should talk to their doctor to find sources of fiber that won’t cause an allergic reaction.
In some cases, a person may want to talk to their doctor about fiber supplements. A doctor may recommend them if the person has constipation or has difficulty passing stool. Pharmacies sell fiber supplements, such as Metamucil, Citrucel, and FiberCon.
These products do not provide the same levels of vitamins and nutrients as natural foods high in fiber, but they are beneficial when someone cannot get enough fiber in their diet.
People can increase their daily fiber intake by making a variety of small changes:
- eat fruits and vegetables with the skin on, as the skin contains a lot of fiber
- add beans or lentils to salads, soups and side dishes
- replace white breads and pasta with whole wheat versions
- aim to eat 4.5 cups of vegetables and 4.5 cups of fruit each day, as the
American Heart Associationto suggest
- if you cannot meet daily needs, consider using fiber supplements
Dietary fiber is an essential part of a healthy diet, with research linking a diet high in fiber to reduced risks of many health problems, including cardiovascular disease, type 2 diabetes and certain cancers. Fiber is also important for keeping the gut healthy.
Most people in America do not meet their daily fiber requirements. People can increase this measurement by eating more foods high in fiber, fruits and vegetables with the skin on, or by taking fiber supplements if this is not possible.