In Latin, "fiber" means "thread, rope, fiber", and belongs to the nutrients that are not broken down by the enzymes of the gastrointestinal tract.

What is fiber?

Fiber is a type of carbohydrate but, unlike other substances in the group, it cannot be broken down into digestible glucose molecules.

Thus, the fiber passes through the entire digestive tract almost unchanged. However, fiber does a lot of work along the way. This substance is of great importance for proper digestion and weight correction, regulation of sugar and cholesterol levels in the blood. There is also an opinion that fiber is one of the factors preventing the development of cancer. Some speak of it as a substance that prolongs the youth of the body.

Daily Values ​​

Researchers say that the average woman consumes about 13 g of fiber daily, and men - about 17 g. Meanwhile, nutritionists found that fiber is so important for a person that it should be present in the diet daily. At the same time, men under 50 should consume about 38 grams of fiber per day, older - about 30 grams. Women under 50 years of age are recommended to consume about 25 g of the substance daily, and 21 g per day is enough for ladies after 50. Providing yourself with these portions is not difficult if the daily diet contains whole fruits and vegetables, nuts and seeds.

The required amount of fiber for children is determined taking into account age categories: children under 3 years old should receive 19 g of the substance per day, 4-8 years old - about 25 g per day, girls 9-18 years old - 26 g each, boys 9-13 years old - 31 g each, boys 14-18 years old - 38 g each.

Nutritionists say that the ratio of insoluble to soluble fiber should be 75% to 25%. But since many products (hercules, bran, flax seeds, and others) contain two types of dietary fiber, you should not specifically deal with calculating proportions.

Soluble vs. insoluble fiber

Dietary fiber consists of non-starch polysaccharides such ascellulose, dextrins, inulin, lignin, chitin, pectins, beta-glucans, waxes and oligosaccharides.

There are two main types of fiber: soluble and insoluble.

Soluble fiber

Soluble fiber, as the name implies, dissolves in the aquatic environment, and passing through the digestive tract, amenable to fermentation, after which it acquires a jelly-like consistency. It slows down the digestion process, resulting in a feeling of satiety for a longer time. Thanks to this ability, it helps to control appetite, and hence weight.

Benefits of soluble fiber:

  • lowers "bad" cholesterol;
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  • regulates blood sugar concentration, which is important for diabetics and people with metabolic syndrome.

Soluble fiber foods: fruit pulp, beans, peas, carrots, oats, linseeds. All these products in the body dissolve to a gel-like texture.

Insoluble fiber

Benefits of insoluble fiber:

  • promotes proper bowel movement and prevents constipation;
  • accelerates the elimination of toxins from the body through the colon;
  • maintains an optimal level of acidity in the intestines.

Insoluble fibers retain their shape during all stages of digestion. Accelerates the passage of food through the digestive tract and its excretion, which prevents constipation. Examples of insoluble fiber are hemicellulose, cellulose, and lignin.

Foods rich in insoluble fiber: vegetables and fruits (peel), beans, herbs, nuts, seeds.

Many foods contain both soluble and insoluble fiber. But their proportions vary. Meanwhile, substances from both categories have a beneficial effect on the work of the body.

Benefits for humans

Regular intake of fiber is very important for the health of the body. For example, soluble fiber intake is known to protect against the development of heart disease, in particular by lowering the concentration of cholesterol. The insoluble substance reduces the risk of constipation, colitis, colon cancer, hemorrhoids. Researchers say eating fiber-rich foods reduces the risk of diverticulitis (small bulges in the colon). Also, with the help of dietary fiber, you can get rid of irritable bowel syndrome. People with diabetes who consume a lot of this substance usually need less insulin. It has a beneficial effect on the functioning of the kidneys and gallbladder, in particular, preventsthe formation of stones in organs.

Fiber and…


Dietary fiber helps lower cholesterol levels. The process of digesting food requires bile acids, which are partly composed of sterol. To improve digestion, the liver pulls cholesterol from the blood to create bile acids, thereby reducing the concentration of so-called "bad" cholesterol.

…heart health

An association has also been found between fiber intake and heart attack risk. In people whose diet is based on foods rich in fiber, the risk of heart disease is reduced by 40%. And it is enough to increase your daily portion of fiber by 7 grams to reduce the risk of a heart attack by 7%.

…blood sugar

Studies have shown a link between fiber and blood glucose levels. American scientists have noticed that an increased intake of fiber fibers can lower glucose levels. In addition, the risk of developing diabetes mellitus is reduced in people who consume enough fiber daily. Soluble fiber helps slow down the breakdown of carbohydrates and the absorption of glucose, which helps control blood sugar levels.


A 2011 study showed a potential relationship between fiber intake and cancer risk. Then a group of scientists conducted a control experiment on animals, and this time the researchers found that such a connection still exists, but subject to the presence of the correct microflora in the intestine. In this case, the fiber reacts with bacteria in the lower part of the large intestine. As a result of fermentation, a reagent called butyrate is produced. It is this substance that causes the self-destruction of cancer cells.

But this is not the only cancer affected by fiber. Recently, scientists from Nebraska announced the results of another study. In their opinion, fiber, oddly enough, can prevent lung cancer. The study found that 68 percent of those who consumed 18 grams or more of fiber per day had excellent lung health. Also, lovers of products containing fiber were the best in another test - on lung capacity. How to explain this relationship, scientists do not yet know.

... longevity

According to many scientists, the secret of longevity lies precisely in dietary fiber. And American epidemiologists believe that high-fiber foods can reduce mortality. And they add: wheat fiber and whole grain products are especially useful for humans. The result of a 14-year follow-up showedthat people whose diets contain these foods have a 19 percent lower risk of death. By the way, some studies suggest that in ancient times the diet of our ancestors included at least 60 g of dietary fiber per day.


On top of all that, fiber also plays a role in preventing food allergies. This theory is again explained by the relationship between fiber and gut bacteria.

Scientists suggest that people with disturbed intestinal microflora are prone to food allergies, in particular those caused by peanuts, crustaceans and shellfish. And dietary fiber activates the reproduction of Clostridium bacteria, on which the proper functioning of the organ actually depends.

List of foods with healthy fiber for people with food allergies: apples, pears, melon, carrots, potatoes, rutabaga, broccoli, green beans, pumpkin, zucchini. They have a high concentration of vegetable fiber and at the same time are hypoallergenic products.


A similar explanation applies to the effectiveness of fiber in treating asthma. One of the reasons for the development of autoimmune diseases is that, as a result of digestion failure, particles pass from the intestine into the bloodstream and cause inflammation. An experiment conducted on rats showed that a more intensive intake of dietary fiber reduces asthmatic inflammations.

…weight loss

By maintaining a feeling of satiety for a long time, fiber helps to get rid of excess weight. Therefore, all diets for obese individuals should contain the maximum amount of dietary fiber. The average daily intake of dietary fiber in this case should be about 60 g. In this case, you can resort to the use of pharmacy fiber. You can drink it on your own: dilute a tablespoon of the substance with a glass of water and drink 30 minutes before meals (but not more than 6 tablespoons per day). A more pleasant way is to add the substance to ready-made dishes (soups, broths, yogurts, salads). There is a diet, the essence of which is to drink a liter of kefir and 6 tablespoons of fiber per day. This diet menu can be used as a 1-day unloading or observed for several days.

…healthy skin

The fiber contained in psyllium helps to eliminate bacteria and fungi that cause acne and rashes from the body. So, at least, say some researchers. There are many other reasons why you should consume enough of this substance. For example, most fiber foods are high in vitamins and other nutrients needed to keep skin healthy.

Fiber in the formSupplements

People who want to significantly increase their fiber intake resort to all sorts of supplements. But nutritionists remind us that fiber from dietary supplements is not as useful as a natural substance from food. Such supplements can be useful for people with digestive disorders, in particular for getting rid of constipation. Also, supplements of this kind are useful for weight loss, lowering cholesterol and stabilizing blood sugar.

But when resorting to the use of fiber in the form of dietary supplements, one must be prepared for flatulence. In addition, the substance affects the bioactivity of certain drugs, including aspirin.

Diet rich in fiber

Diet rich in fiber is very beneficial for health. But it is important to switch to a new nutrition program gradually, adding 5 g of the substance per day. A faster transition can cause bloating, cramps, diarrhea. Also, nutritionists from the University of Michigan advise to slightly reduce the amount of caffeinated drinks while taking fiber. Caffeine acts as a diuretic in the body, and fluid loss due to high fiber intake is fraught with constipation.

Dietary fiber will help replenish the diet, it is not necessary to immediately resort to taking dietary supplements. To do this, pay attention to fruits and berries. Ideally, they should be consumed in small portions throughout the day. The next recommendation of nutritionists is to start the day with oatmeal or bran with berries. As for protein foods, in addition to meat, it is important to include vegetable proteins (beans, beans, lentils) in the diet, which are also excellent sources of fiber. Broccoli, greens, corn, whole grain pasta, and brown rice are perfect for a fiber-enriched dinner.

Fiber-rich menu options


  • whole grain oatmeal;
  • whole grains;
  • wholemeal/buckwheat pancakes with fruits or berries;
  • bran with fruit;
  • a mixture of cereals rich in fiber;
  • Hercules with apples, oranges, berries, bananas, almonds.


  • wholemeal pasta;
  • brown rice;
  • bean dishes;
  • Egg and cheese/turkey/cheese and vegetable cornmeal tortillas;
  • lentil dishes;
  • baked potatoes with skins;
  • cabbage dishes.


  • wholemeal cookies and muffins;
  • bran pastries;
  • yoghurt with fruit and berry filling and cereals;
  • cinnamon apples;
  • fruit salads.
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Food Fiber Table


Fiber (g)
Bran 44
Flax seeds 27
Mushrooms 25
Rosehip (berries) 22
Figs 18
Rye 16
Almond 15
Green peas 12
Whole wheat 10
Whole grain bread 8.5
) Brazil nut 7
Chestnuts 6.8
Corn 6
Peas 5.8
Raspberry 5
Strawberry 4
Beans 4
Lentils 3.8
Dates 3.5
Bananas 3.5
Dried apricots 3.2
Raisins 3
Oatmeal 2.8
Currant 2.5
Pasternak, parsley 2.4
Gooseberry 2
Rhubarb 1.8
Orange 1.5
Olives 1.5
Bell peppers 1.4
Pineapples 1,2
Pumpkin, carrot 1.2
Peaches, Apricots 0.9
Cauliflower 0.9
Radishes 0.8
Wheat porridge 0.7

When to cut back on fiber

Fiber can be good and bad. The latter occurs when you do not listen to the advice of doctors. So, sometimes there are situations when people, at least for a while, should stick to a diet low in fiber. This usually applies to people undergoing chemotherapy, after radiation, or before/after surgery. In such cases, it is necessary to ensure the rest of the gastrointestinal tract. But people with Crohn's disease, inflammatory bowel disease, diverticulosis, and ulcerative colitis will need to stick to a low-fiber diet for a longer time.

Chronic GI disease, diarrhoea, flatulence, reflux, food allergies, and intolerance to certain foods are reasons to reduce fiber intake.

The human digestive system is not designed to break down fiber. The undigested substance enters the intestines, where beneficial bacteria (probiotics) feed on fiber and multiply in it. However, if pathogenic bacteria or fungi “settled” in the intestines, the fiber will serve as a breeding ground for these microorganisms, which, you understand, will only aggravate the painful condition caused by pathogenic microflora. For this reason, fibrous matter should be discarded until a healthy balance of intestinal bacteria is restored. This will allow, so to speak, to eradicate microorganisms unusual for humans by starvation.

In such cases, legumes, whole grains, raw vegetables and fruits should be avoided. Also, do not abuse meat, caffeine,, fried and spicy foods, cut portions of cocoa and nuts. Instead, it is better to focus on refined grains, boiled vegetables, ripe melons, peaches, plums, bananas and apricots.

Excessive fiber intake: benefits and harms

Fiber is one of the main nutrients for the body. Adhering to the recommended daily allowances, you can achieve excellent results. But at the same time, consuming large amounts of fiber, without following some rules, can cause unpleasant side effects. Studies have shown that consuming too much fiber can increase the risk of diseases such as diverticulosis (intestinal protrusions). In addition, food that is excessively saturated with fiber is harmful to the diseased intestines.

Consequences of excess:

  1. Imbalance of nutrients.

Eating lots of fiber while neglecting other nutrients? Then be prepared for a shortage of useful elements. Many fiber foods are high in carbohydrates and very low in protein and in fat. Protein meals and healthy lipids will help prevent imbalances. It is also important to know that dietary fiber interferes with the absorption of vitamin B2.

  1. Digestive discomfort.

Fiber is known to aid digestion. And it is true. But the consumption of extremely high doses can play a cruel joke and affect the body in the opposite way. Among the consequences of excessive consumption of fibrous foods are abdominal cramps, diarrhea, bloating and even intestinal blockage.

  1. Mineral deficiency.

It is believed that regular consumption of large portions of fiber prevents the absorption of minerals such as iron, zinc, magnesium and calcium. This effect is caused by insoluble substances. Therefore, nutritionists recommend drinking plenty of water and eating other nutrient-rich foods in addition to fiber intake.

How to take fiber properly

  1. Increase your fiber intake gradually.
  2. Drink plenty of water.
  3. Exercise (yoga, walking) - they increase intestinal motility.
  4. Excessive consumption of nuts, flax seeds, or carrots can cause flatulence.
  5. Magnesium supplements can be taken if constipation occurs.

As you already understood, the body needs fiber daily and in the right amount. She, like a brush, cleans out everything unnecessary, but at the same time, she helps the digestive system, and not only her, to perform its functions. Well, when the body works like a well-oiled mechanism, then the appearance only benefits from this.