Dietary fiber is a carbohydrate found in plants that the human body cannot actually digest, but it still plays an essential role in the digestive system, the health, and for the proper digestion of all essential nutrients.
Fiber can be soluble and insoluble (3).
The soluble fiber can attract and absorb water, and as a result, can turn into a gel during the digestive process. Soluble fiber is found in barley, oat, bran, seeds, nuts, beans, peas, lentils, and in some vegetables and fruits like berries, apples, and bananas.
Certain types of soluble fibers can help reduce the risk of heart disease and have multiple health benefits, including weight loss, resolving constipation issues, reducing blood sugar levels and cholesterol, and many others (4).
Insoluble fiber cannot be digested and adds bulk to the forming stool in the GI tract, speeds up the passing of the stool, and helps to eliminate the waste from the digestive system more efficiently.
Insoluble fiber is found in wheat bran, whole grains, and in some vegetables and the skins of various fruits (5).
Both types of dietary fiber are used as food for the beneficial bacteria in the large intestine, and help add bulk to the stool, and speed up its elimination.
Both soluble and insoluble fiber helps bulk up your stools and can be used as a food source for good bacteria in your large intestine.
Basic facts you should know about fiber
There are many definitions of fiber, and sometimes it can be referred to as roughage or bulk, but overall, dietary fiber is a nutrient which consists of non-digestible carbohydrates as well as lignin found in plants. It includes the nonstarch polysaccharides in plants, such as cellulose, gums, pectin, hemicellulose and the fibers in wheat bran and oats, as well as lignin, oligosaccharides and resistant starch.
The so-called functional fiber has beneficial effects on humans. It includes the non-digestible plant parts like pectin, resistant starch, and gums, as well as chitosan, chitin, or some commercially produced carbohydrates, such as inulin, polydextrose and indigestible dextrins.
The total fiber is the whole sum of the consumed dietary and functional fiber. It is the total fiber you intake that makes a difference for your digestive and overall health.
Fiber is a carbohydrate, but it doesn’t have so many calories and is not digested and absorbed by the GI tract as carbohydrates do.
How much fiber do you need every day?
According to the American Heart Association Eating Plan, the recommended daily intake of fiber is 25 grams for a 2,000 calorie diet. The AHA recommends that you eat at least half whole grains of all grains in your diet, such as whole-grain bread, whole-grain cereal, brown rice, whole-wheat pasta, whole-grain crackers, unsalted air-popped popcorn or whole wheat tortilla (6).
According to the Institute of Medicine, men need to eat 38g and women need to intake 25g of fiber a day (7).
Ways to increase your fiber intake to reach the recommended daily intake
Here are some simple ways to increase your consumption of healthy fiber on a daily basis:
- Try to add at least one serving of whole-grain foods or cereals in each meal
- You can sprinkle oat bran or wheat germ on your salads, cereals, yogurt or soups
- Use whole wheat flour for baking and cooking whenever possible
- Choose whole-grain bread with high amounts of fiber
- Eat cereals which have at least 5g of fiber per portion
- Snack on whole-wheat crackers
- Use brown instead of white rice when preparing your food
- Add kidney, garbanzo or other beans to your salads
- Add legumes instead of meat in your soups or chili at least 2-3 times a week
- Try out some Indian or Middle Eastern dishes which are rich in legumes and whole grains
- Eat at least 5 servings of veggies and fruits a day
- Eat the peels of the fruits and vegetables when possible
- Stick to fresh rather than canned fruits
- Eat the whole foods instead of drinking juices
- You can add dried fruits to your baking goods such as pancakes, muffins, and others
- Eat your cereal with sliced peaches, bananas or other fruits
- Add more grated carrots to your salads
- Eat more whole apples, tangerines, oranges, pears, strawberries or blueberries
- Add peas, sweet potatoes, squash, cauliflower and carrots to your meals
The foods which will supply you with the soluble fiber you need to be healthy
Soluble fiber has been proven to reduce the total cholesterol and the bad LDL cholesterol levels, as well as the blood sugar levels.
Here are some healthy foods which you should eat more in order to get the recommended daily doses of soluble and total fiber, essential for your digestive and overall health:
Black beans are excellent alternatives to meat in many dishes, as they themselves have meat-like texture.
A single cup of black beans contains 15g of fiber which is about 40-60 of the recommended daily intake for both men and women (7).
They are an excellent source of pectin which is a soluble fiber which becomes gel or gummy like when in contact with water.
It can help delay the emptying of the stomach and make you feel fuller for a longer time, as well as allow for all vital nutrients to be absorbed by the body (8).
Black beans are low in calories, have almost no fat, and are a healthy source of iron and protein (9).
The soluble fiber content is 5.4g per 129g of cooked black beans (10).
Whether you like Brussels sprouts or not, the truth is that they are incredibly healthy and are a rich source of vitamins, minerals, and antioxidants.
Plus, Brussels sprouts are an excellent source of soluble fiber. They contain 4g of fiber per cup (11).
The soluble fiber in the Brussels sprouts helps feet the beneficial gut bacteria in the large intestine. They also contain vitamins B and K, and short-chain fatty acids which are essential for the health of the gut lining.
The soluble fiber content is 2g per ½ cup (78g) of Brussels sprouts (12).
Oats are among the healthiest and most versatile grains. They can be used as breakfast cereals, as food crumbles, for making bread and others.
Oats contain beta-glucan which is a soluble fiber known to reduce the levels of LDL cholesterol and the blood sugar in the blood.
About 3g of beta-glucan per day can help reduce the risk of heart disease significantly (13).
It is the beta-glucan in the oats, which gives the oatmeal its creamy texture.
The soluble fiber content is 1.9g per 1 cup (233g) of cooked oats (16).
Although you may think that barley is used only for brewing, the fact is that it is a very nutritious grain which is used to thicken stews, soups, and risottos.
Barley contains an average of 3.5-5.9% of beta-glucan which is the soluble fiber known for reducing the risk of heart disease.
The other soluble fibers found in barley are pectin, psyllium and guar gum (17).
The soluble fiber content is 0.8g per ½ cup (79g) of cooked barley (17).
Sweet potatoes are rich in beta-carotene and potassium, as well as B vitamins and dietary fiber.
A medium-sized potato contains 4 times the recommended daily intake of vitamin A as well (18).
It also contains approximately 4g of fiber, of which half is soluble fiber (19).
Soluble fiber is known to benefit weight management and help promote weight loss because it boosts the release of the hormones responsible for the feeling of fullness, which can help reduce the appetite (20).
The soluble fiber content is 1.8g per ½ cup (150g) of cooked sweet potato (21).
Avocados have become one of the most popular foods around the world, with people looking for healthy and nutrient-rich fruits and vegetables to add to their diets.
The Avocado contains vitamin E, monounsaturated fats and about 13.5g of dietary fiber per fruit.
1/3 avocado has 4.5g of fiber, of which 1.4 are soluble fibers (22).
Avocados also happen to be rich in insoluble fiber too.
The soluble fiber content is 2.1g in ½ avocados (23).
Broccoli is another veggie which is filled with healthy vitamins, minerals, antioxidants, and dietary fiber.
Broccoli is rich in vitamin K, potassium, folate and vitamin C, as well as in antioxidants (24).
It also contains about 2.6g of fiber per 100g, half of which at least are soluble (25).
The soluble fiber in broccoli helps feed the good bacteria in the large intestine and thus help the production of short-chain fatty acids like acetate and butyrate.
The soluble fiber content is 1.5g per ½ cup (92g) of cooked broccoli (26).
A favorite of vegetarians and vegans, kidney beans are almost fat-free and yet are an excellent source of protein and complex carbs, as well as dietary fiber.
Kidney beans contain calcium and iron and are rich in soluble fiber, especially in pectin (27).
Since some people find kidney beans difficult to digest, you should start adding them gradually to your diet in order to avoid bloating and flatulence.
The soluble fiber is 3g per ¾ cup (133g) of cooked kidney beans (28).
These delicious large beans also known as butter beans are rich in protein, carbs and a little fat.
They have lower amounts of dietary fiber than black beans but have almost the same amount of soluble fiber, namely pectin.
Pectin is known to help reduce blood sugar spikes after eating (29).
Lima beans need to be soaked and boiled before consuming them because they can be toxic when they are raw.
The soluble fiber is 5.3g per ¾ cup (128g) of boiled lima beans (30).
Pears are juicy and delicious fruits which are an excellent source of vitamin C, potassium, antioxidants and fiber.
Pears are also high in sorbitol and fructose, which can have a laxative effect. People with irritable bowel syndrome should be careful with the amounts of pears they consume (33).
The soluble fiber content is 1.5g per 1 medium-sized pear (34).
Figs are among the most ancient cultivated fruits in the world. They are not only delicious but are also rich in calcium, potassium, magnesium, B vitamins and soluble fiber.
The soluble fiber in figs can help slow down the movement of the food through the digestive system and thus allow for better absorption of the vital nutrients (35).
They are known to help resolve problems with constipation too.
The soluble fiber content is 1.9g in ¼ cup (37g) of dried figs (36).
Apricots are sweet and delicious small fruits which are low in calories and rich in vitamins C and A.
Apricots have been used in traditional Asian medicine for protection against heart disease (39).
They can also help the digestive system, thanks to their insoluble and soluble fiber content (40).
The soluble fiber content is 1.4g in 3 apricots (41).
Nectarines are similar to peaches, but without the characteristic fuzzy skin on the latter.
A single average-sized nectarine has 2.4g of fiber, of which at least half is soluble.
Carrots are among the most popular vegetables worldwide.
They are used for endless different meals, as well as desserts such as carrot cake, or for salads.
Young children are taught to eat carrots in order to improve their vision especially the night vision.
This happens to be true because carrots are very rich in beta carotene, some of which gets converted to vitamin A which is essential for night vision in humans (46).
A cup of chopped carrots (128g) has 4.6g of dietary fiber, of which about 2.4g are soluble fiber.
Carrots are so popular, that they can easily become the important single source of soluble protein in anyone’s diet.
You all know the saying “an apple a day keeps the doctor away.”
Apples are possibly one of the most common fruits around the worlds. There are various sorts of apples, most of the sweet, but others quite sour as well.
Eating apples is known to be associated with a lowered risk of a number of different chronic diseases, so the proverb about the apple a day may be actually true (49).
These fruits are rich in various vitamins and minerals, as well as in the soluble fiber pectin.
The soluble fiber is 1g per 1 medium-sized apple (52).
These exotic fruits are native to Mexico and other Central and South American areas and countries. They have green skins and white to deep pink pulp.
Soluble fiber like pectin can help delay the absorption of sugar by the body and thus help prevent blood sugar spikes after eating. It has also been found to reduce the total cholesterol, the bad LDL cholesterol and the blood sugar levels too (55).
The soluble fiber content is 1.1g per 1 raw guava fruit (56).
These root vegetables come in different varieties, some of which are used for feeding livestock, but others are also popular ingredients of different salads and meals.
Turnips are abundant in potassium, calcium, and vitamins K and C (57).
They can increase your fiber intake too because a cup of these veggies contains about 5g of dietary fiber, of which approximately 3.4g are soluble (58).
The soluble fiber content is 1.7g per ½ cup (82g) of cooked turnips (59).
Sunflower seeds are not only a favorite food for birds, but can also be a delicious and nutritious snack for people as well.
They are commonly sold deshelled for easy consumption of the tasty sunflower hearts.
Sunflower seeds contain about 3g of dietary fiber, 1g of which is soluble.
These seeds are also rich in polyunsaturated and monounsaturated fats, protein, selenium, magnesium, iron and other nutrients (60).
The soluble fiber content is 1g per ¼ cup (35g) of sunflower seeds (61).
Flaxseeds are tiny yellow, brown and golden seeds also known as linseeds.
They are a common addition to the morning breakfast and to various smoothies, cereals, bread, and other foods.
Flaxseeds contain a lot of fiber and protein, so a single tablespoon is a source of about 3.5g of fiber and 2g of protein.
They also contain a lot of plant-based omega 3 fatty acids (62).
For the best results, soak the flaxseeds overnight to allow for the soluble fiber to combine with the added water and to form a gel which is beneficial for the digestive system.
The soluble fiber content is 0.6-1.2g per tablespoon (14g) of whole flaxseeds (63).
These delicious nuts can be enjoyed raw or roasted, and are commonly used in various sweet baked goods, chocolates and spreads.
Just ¼ cup of hazelnuts can provide you with 3.3g of dietary fiber, 1.1g of which are soluble.
Hazelnuts, thanks to their high soluble fiber content can help reduce the bad LDL cholesterol levels and thus help reduce the risk of heart disease (66).
The soluble fiber content is 1.2g per ¼ cup (34g) of hazelnuts (67).
Soluble fiber is essential for your digestive health as well as for your overall health.
It can help promote weight loss, reduce the risk of heart disease, and help lower the blood sugar levels of people with diabetes.
Soluble fiber is known to promote weight loss by providing a sated feeling for longer, by helping lower the caloric intake, and by acting as a probiotic which feeds the friendly bacteria in the gut and helping reduce weight gain (68, 69, 70, 71).
Soluble fiber also helps the increase of the growth of the beneficial gut bacteria, preventing symptoms of hay fever, improving skin conditions and acne, and reducing thyroid hormone levels in people with hypothyroidism (72, 73, 74, 75).
In order to increase the intake of soluble fiber and reach the recommended daily intake, it is advisable to introduce the high fiber foods slowly and increase it gradually.
Also, remember to drink a lot of water, which will help the soluble fiber turn into a gel-like substance which helps aid the digestion.
So, go ahead and start eating more foods rich in soluble fiber today, to enjoy the multiple benefits which are associated with it!