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Types of fiber in food (not all are ideal)

Different types of fiber

Fiber is a very interesting element provided in the diet can influence many aspects of health. From influencing the number and variety of gut bacteria to weight loss, and is considered a fundamental part of a healthy diet. However, there are different types of fiber and not all of them are so advantageous.

Most people have a fairly simple idea of what dietary fiber is and tend to encompass it in a single category. However not all are the same and there are different types of fiber

In some cases they are very beneficial for health, and in others they can cause digestive disorders. In this article we want to explain what you need to know about the different types of fiber.

What exactly is dietary fiber and how is it classified?

Fiber encompasses a varied group of carbohydrates that humans are not able to digest. This is because we lack the digestive enzymes that are required for its breakdown, so it passes through most of the digestive system without being altered. Therefore, and depending on several categories, we find different types of fiber.

The recommended amount of fiber intake is around 38 g for men and 25 g for women. On the other hand, the vast majority of people only ingest about half of what is necessary, between 15 and 17 g daily.

Fiber is mainly found in vegetables (fruits, legumes, and seeds). There is a wide variety of different types of fiber that can be found in food.

The problem is that, many times, they are classified in different ways, which can create confusion.

There are 2 types of fiber mainly:

  • Dietary fiber: that fiber that we can find in food.
  • Functional fiber: that fiber that is extracted and isolated from whole foods and added to processed foods.

However, there is a major problem when performing this classification of fiber types, since is not saying anything on its beneficial or harmful effects on health.

A recent method of classification is to do so based on its solubility, viscosity and fermentation capacity. Subsequently, there is also another type known as resistant starch, which is not a fiber but can have the same effects.

Types of fiber: soluble or insoluble?

The solubility of fiber tells us the ability it has to dissolve in water.

Because of this, fiber has often been classified by its solubility.

  • Types of soluble fiber: it mixes with water in the intestine, creating a gelatinous-type substance. It has the ability to reduce blood sugar spikes and offers several benefits for metabolic activity.
  • Types of insoluble fiber: it does not solubilize with water and crosses the digestive system without modifying its properties. It acts primarily as a transportation agent and helps speed up the passage of food and waste through the gut.

Among the types of soluble fiber we find the so-called gums, pectins, psyllium, beta-glucans and others. Insoluble fibers include lignin and cellulose. It depends on the food ingested the proportion and type of soluble and insoluble fiber.

Types of fiber: fermentable

Our human gut houses about 100 trillion live bacteria, especially inhabiting the large intestine. These bacteria are essential to ensure optimal health in humans.

They perform various functions related to body weight, blood sugar regulation, activity on the immune system, brain function and mental health.

Fiber reaches the gut virtually intact, and this is where the microbial population. Fermentable fiber is one that bacteria and microorganisms can digest (ferment) and use as the basis of their diet.

This guarantees a constant supply of the microbial population, which in turn also guarantees the production of short-chain fatty acids with a multitude of benefits for our health.

The vast majority of types of fermentable fiber are soluble, but there are also some that are insoluble, but thatthey are fermented. Among these types of fibers we include pectins, beta-glucans, guar gum, inulin and oligofructose.

One of the foods that provides the highest concentration of fermentable fiber are the vegetables and the Beans. In fact, one serving can provide up to half of the recommended daily amount.

Hence, when we take legumes, we have flatulence, because in the fermentation process gas is produced.

Types of fiber: viscose

Some types of soluble fibers create a thick, viscous gel when mixed with water. This type of fiber is known as viscous.

When we ingest viscous-type fiber, a gelatinous substance is created that sticks to the intestine. This slows down digestion and therefore nutrient absorption, resulting in a prolonged feeling of satiety and reduced appetite.

Therefore, when we talk about fibers, only viscous can have an effect of reducing appetite and generating weight loss.

Among this type of fibers we find glucomannan, beta-glucans, pectins, guar gum and psyllium, found in foods such as legumes, asparagus, Brussels sprouts, cereals such as oats and flax seeds.

Resistant starch

Starch is a type of carbohydrate included in our daily diet. It is formed by long chains of glucose, and we can find them in foods such as potatoes, bananas, legumes, oats, cashews and a wide variety.

Some of this starch is resistant to digestion, so like insoluble fiber, it passes through the digestive system undisturbed. That is why it is known as resistant starch, and acts in the same way as fermentable soluble fiber in the intestine.

The resistant starch it has numerous health benefits. It is able to improve digestive health, increase insulin sensitivity, lower blood sugar levels and reduce appetite.

Types of healthy fibers

Several fibers have specific implications for health and are worth mentioning and contrasting.


The fructans describe a small chain of fructose molecules. Oligofructose and inulin are the two main varieties of fructans that we provide in our diet. They are able to feed the beneficial bacteria that inhabit ours, and it has been scientifically proven that they can favor the treatment of diarrheal processes.

However, there are also drawbacks in fructans, since this type of carbohydrate can cause digestive disorders in sensitive people.

The largest source of fructans in our modern diet is found in the wheat.

Beta glucan

The benefits for our organism of the beta-glucans have been extensively documented in different clinical trials. This type of fiber has a specific molecular structure that makes them highly viscous when they pass through the intestine.

Beta-glucans can improve insulin sensitivity and reduce sugar levels in the bloodstream. In addition, they can considerably reduce cholesterol levels and increase feelings of fullness.

The main food sources with beta-glucans are oats and barley.


Glucomannan is a type of viscous fiber that is sold as a specific supplement for weight loss.

Barios studies have shown that glucomannan can cause moderate weight loss, reduce constipation, and improve risk factors for heart disease.


About Andrew Parkinson

Andrew Parkinson is a highly accomplished pharmacist with a passion for improving healthcare. With a wealth of experience in both community and clinical pharmacy settings, he's known for his dedication to patient well-being. Mr. Parkinson actively engages in medication management, offering personalized solutions and promoting better health outcomes. He has also played a pivotal role in educating patients on proper medication usage and potential interactions. Andrew's commitment to advancing the field of pharmacy and ensuring safe and effective drug therapies has garnered him recognition as a trusted and invaluable healthcare professional, making a positive impact on countless lives.

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