Fibers are carbohydrates that are not absorbed by the body and that can be found in some foods such as fruits, vegetables, grains and cereals, for example. Adequate consumption of fiber in food is important to maintain the health of the intestine and prevent diseases such as constipation.
In addition, fiber, especially soluble, also helps to regulate blood glucose levels and increases the feeling of satiety, fighting diseases such as diabetes and obesity. Therefore, the daily fiber recommendation for an adult is between 25 and 38 grams.
Fiber Benefits
In general, the health benefits of fiber are:
- Combat constipation, as they accelerate intestinal transit and increase the volume of feces and facilitate its elimination, especially when consumed together with adequate amounts of water.
- Increase the feeling of satiety, since as they are not digested, they create a kind of gel in the stomach, helping to reduce the calories that are ingested and favoring weight loss;
- Help to regulate blood sugar levels, because the absorption of carbohydrates at the intestinal level is slower, causing glucose to increase progressively and insulin to regulate its levels;
- Decrease the levels of cholesterol and triglycerides, as fibers are able to decrease the absorption of fats and cholesterol at the intestinal level, causing them to decrease their concentration in the body in the long term;
- Eliminate toxins found in the intestine,through feces, as well as control and regulate the pH in the intestine;
- Maintain the health of the intestinal flora and the gastrointestinal system, as they serve as food for the beneficial bacteria that are naturally present in the intestine. In addition to promoting the health of the intestinal microbiota, the fibers decrease inflammation, increase the body’s defenses and prevent the formation of intestinal diseases.
To get the full benefits of fiber, it is necessary to consume fiber-rich foods daily with all main meals and snacks. It is also important to mention that when eating a diet rich in fiber, it is necessary to increase the intake of water, since water hydrates the fiber and lubricates the intestine, facilitating the elimination of feces and improving constipation.
List of high fiber foods
The following table shows the foods richest in fiber and in what quantities they have it:
| Cereals | Quantity of fibers (100 g) |
| Wheat bran | 30 g |
| Rye flour | 15.5 g |
| Oats | 9.1 g |
| Cooked brown rice | 2.7 g |
| Whole wheat bread | 6.9 g |
| Vegetables, vegetables and derivatives | |
| Cassava flour | 6.5 g |
| Sauteed kale | 5.7 g |
| Cooked broccoli | 3.4 g |
| Raw carrot | 3.2 g |
| Baked sweet potato | 2.2 g |
| Green pepper | 2.6 g |
| Baked pumpkin | 2.5 g |
| Raw pumpkin | 1.6 g |
| Lettuce | 2 g |
| Fruits and derivatives | |
| Persimmon | 6.5 g |
| Avocado | 6.3 g |
| Guava | 6.3 g |
| Earth orange | 4.1 g |
| Apple | 2.0 g |
| Plum | 2.4 g |
| Banana | 2.6 g |
| Nuts and seeds | |
| Linseed | 33.5 g |
| Almonds | 11.6 g |
| Chestnut of Pará | 7.9 g |
| Raw coconut | 5.4 g |
| Cashew nut | 3.7 g |
| Peanut | 8.0 g |
| Sesame seeds | 11.9 g |
| Legumes | |
| Soy flour | 20.2 g |
| Cooked carioca beans | 8.5 g |
| Green bean | 9.7 g |
| Cooked lentils | 7.9 g |
| Pea | 7.5 g |
| Chickpeas | 12.4 g |
| Black bean | 8.4 g |
Types of dietary fiber
Dietary fibers can be classified as being soluble or insoluble, the main difference between them being that the soluble fiber dissolves in water, while the insoluble fiber does not. Each of them has its main benefits.
Soluble fibers
The soluble fibers dissolve in the water forming a gel, and so they stay longer in the stomach and small intestine, thus giving a greater feeling of satiety.
In addition, soluble fibers are metabolized and fermented by the good bacteria present in the intestine, which helps to maintain intestinal health and reduce inflammation, preventing the appearance of gastrointestinal diseases, such as Crohn’s disease, ulcerative colitis and irritable bowel, in addition to also preventing colorectal cancer, which can therefore be considered as a prebiotic.
These fibers also bind to the fat and sugar in foods in the intestine, helping to lower cholesterol and control blood sugar.
Some soluble fibers are pectin and inulin, for example, which can be found in foods such as fruits, vegetables, grains and foods that contain oats, wheat germ, barley and rye. See more about foods rich in soluble fiber.
Insoluble fibers
Insoluble fibers do not dilute in water and their fermentation in the intestinal microbiota is limited, so when they reach the large intestine, they accelerate intestinal transit since it increases the volume of feces and acts as a natural laxative, preventing the occurrence of problems such as constipation, hemorrhoids and inflammation at the intestinal level. They also favor the elimination of toxic products generated at the intestinal level.
Some insoluble fibers are cellulose and lignin, for example, which can be found mainly in whole grains, mainly almonds in shell, chia and linseed seeds, nuts, raisins and in the shell of fruits and vegetables. Check out other foods where insoluble fibers can be found.
Quantity of fibers per day
The daily fiber intake should be between 20 and 40 g per day. A tip for eating more fiber in the diet is to eat more raw and shelled foods, especially fruits and vegetables, avoiding refined foods, such as white wheat flour and white rice.
To combat constipation, it is important to remember that in addition to increasing fiber consumption, you should also increase your intake of water or unsweetened tea, as water hydrates the fibers in the intestine, facilitating the passage of stools. Eating more water-rich foods, such as gelatin, oranges and watermelons, also helps to prevent constipation caused by eating more fiber and less water.
According to the Academy of Nutrition and Dietetics, the daily fiber recommendation varies according to age and sex, as per the following table:
| Group | Amount of fiber in men per 1000 kcal / day | Amount of fiber for women per 1000 kcal / day |
| 0 to 6 months | Only through breast milk | Only through breast milk |
| 6 to 12 months | It was not indicated | It was not indicated |
| 1 to 3 years | 19 g | 19 |
| 4 to 8 years | 25 g | 25 g |
| 9 to 13 years | 31 g | 26 g |
| 14 to 18 years | 38 g | 26 g |
| 19 to 50 years | 38 g | 25 g |
| > 50 years | 30 g | 21 g |
| Pregnancy | – | 29 g |
| Infants | – | 29 g |
How to eat more fiber
A great natural solution for eating more fiber is to add a fiber supplement, such as oats, ground flaxseed or whole wheat bran to all meals throughout the day. It is possible to eat a bowl of fruit salad with oats or to add wheat bran in a yoghurt package, for example. See more details in the following video:
