The benefits of a fiber-rich diet are probably already known to many of our readers, but even so, population research shows that the consumption of foods rich in fiber is below the recommendation.

What are fibers?

Dietary fibers are the parts of food from plant sources that cannot be digested or absorbed by the body.

It belongs to the group of complex carbohydrates, since it does not increase blood glucose levels as simple carbohydrates do.

The components of dietary fiber can be divided into:

  • polysaccharides other than starch-barley, pineapple, pod, psyllium, whole grains, oats, wheat bran, etc;
  • oligosaccharides (non-digestible but fermentable carbohydrates) – chicory, onion, sweet potato, garlic, banana;
  • analogous carbohydrates (resistant starch and resistant maltodextrins) – legumes, seeds, green plantain and polydextrose;
  • lignin – outer layer of cereal grains and celery;
  • compounds associated with dietary fiber (phenolic compounds, cell wall proteins, oxalates, phytates, cutin and suberin waxes) – whole grains, fruits and vegetables;
  • fibers of animal origin (chitin, chitosan, collagen and chondroitin): mushrooms, yeasts, shellfish, invertebrates and shrimp bark.

Fiber types

Fibers can also be classified according to their solubility in water in:

Soluble Fibers

Soluble in water, capable of forming a kind of gel in the large intestine, where it is fermented by bacteria, releasing gases and calories.

Pectin is a type of soluble fiber and belongs to the group of non-starch polysaccharides.

Insoluble Fibers

Insoluble in water and remains intact in the food during the passage through the intestine, increasing the fecal cake and accelerating the intestinal transit, avoiding the cold (stuck intestine).

Cellulose is a type of insoluble fiber also classified as a non-starch polysaccharide.

Fiber recommendation

The fiber recommendation for healthy subjects is as follows:

  • 25 grams for children from 4 to 8 years old and women from 19 to 50 years old.
  • 38 grams for men 19-50.

Of this amount, about 5-10 grams should be insoluble fibers.

Fiber benefits

high-fiber diet is linked to several benefits for general health and well-being.

In addition, it contributes to increasing the consumption of vitamins, minerals and bioactive compounds.


  • Positive modification of the intestinal microbiota (group of bacteria that live in the intestine, also known as intestinal flora), which play an important role in immunity;
  • When fiber consumption is associated with adequate hydration, it helps in intestinal transit, avoiding colds (blocked intestine) and also diarrhea attacks.
  • They promote the feeling of satiety, since the process of digestion of foods rich in fibers takes longer;
  • They reduce the risk of type 2 diabetes by controlling blood glucose levels;
  • They also act in the control of blood glucose after meals in subjects who are already carriers of diabetes.
  • They prevent the development of cardiovascular diseases by improving the lipid profile (fats) in the blood, weight control and blood pressure;
  • They contribute to the reduction of total cholesterol and LDL (considered as “bad” cholesterol) in both adults and children.
  • They act in the control of appetite and, therefore, in food intake and body weight. In this sense, there is no difference between consuming soluble or insoluble fibers;
  • By acting in weight control, they favor the reduction of the abdominal circumference;

It is able to reduce the risk of colon cancer ; due to the alteration of the intestinal flora (prebiotic action).

In addition, they contribute to a lower consumption of fat and, therefore, to the prevention of cardiovascular diseases.

The effects of a high fiber diet:

  • Increased intake of calcium and folate.
  • Increased physical activity
  • There is no possibility of smoking.
  • Decreased intake of meat and alcohol.

Prebiotic effect

To be considered as prebiotic, they must meet the following requirements:

Resistant to digestion and absorption in the small intestine.

Be totally or partially fermented in the large intestine.

Stimulate the growth of selected bacteria.

The fibers that have this effect are inulin and frutoligosaccharides (FOS) and are present in fruits and vegetables, such as bananas or chicory. onion, garlic, leeks and wheat.

These fibers are capable of producing vitamins B1, B2, B6, B12, nicotinic acid, folic acid, and biotin.

Fiber rich diet

Now that you know the benefits of fibers, how about including them in your diet?

The benefits are numerous and contribute to improving the quality of life.

The best thing is that it can be found in everyday foods, such as whole wheat bread, brown rice, granola, in addition to those mentioned above.

However, it should be noted that some foods of fibrous origin may contain what we call antinutritional factors, such as phytate (phytic acid) present in bran and beans.

Phytate binds to minerals such as zinc, iron, magnesium, and calcium, making it difficult to absorb and causing a deficiency.

Meanwhile, eating foods rich in vitamin C and fructose can reduce the effects of phytate when eaten together.

Therefore, it is not necessary to restrict the consumption of fibers, but to include them correctly in the diet. And as always, consulting with a nutrition professional who knows how to adjust your diet to your needs will help you greatly improve your quality of life.

By Dr. Eric Jackson

Dr. Eric Jackson provides primary Internal Medicine care for men and women and treats patients with bone and mineral diseases, diabetes, heart conditions, and other chronic illnesses.He is a Washington University Bone Health Program physician and is a certified Bone Densitometrist. Dr. Avery is consistently recognized in "The Best Doctors in America" list.

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