Why is Fiber Good for Us?
Eat more fiber in your diet.
Wait a moment!
You probably have heard the above recommendation over and over again. However, with so many different types of fiber available, you are probably unsure about which one to choose.
In reality, you are not alone.
Since more and more categories for fiber emerge, it is becoming extremely difficult to know what kind of fiber to choose and nearly everybody is failing to eat enough fibers in their diets.
In this article, I am going to explain why is important to eat a diet rich in dietary fiber, and how to be wisely choosing the fiber we eat in order to have the best benefits.
But first of all, what is dietary fiber made of?
Dietary fibers are mainly found in carbohydrates and are the forage or the indigestible parts/compounds of plant cell walls, and are found almost exclusively in fruits, vegetables, tubers, grains, and legumes.
In plant cells, fiber act as a skeleton that helps to maintain the plants structure, and basically, what separates fiber form other carbohydrates, starches and sugars, is thatit does not undergo the normal digestion and absorption processes as fiber resist to the action of the human digestive enzymes in the small intestine, passing all the way throughout the digestive tract and arriving mainly intact in the large intestine. (1)
A high-fiber diet might provide us many health benefits
Scientific evidence confirms the associations between high-fiber intakes and numerous health benefits such as: (2, 3, 4, 5)
- It keeps us satiated
- It is a great tool for weight-loss that supports a health weight
- It adds bulk to stool and improves regularity in bowel movements
- It serves as food to our gut flora/microbiome
- It helps remove toxins
- It helps reducing metabolic syndrome risk *
- It helps reducing the risk of some types of cancer
- It helps reducing the risk of developing chronic diseases
- It supports the production of short-chain fatty acids (SCFA) such as acetic acid, propionic acid, and butyric acid by the gut bacteria
- It supports the absorption of minerals such as iron, calcium, copper, zinc, magnesium, etc.
- It helps us live longer
*Metabolic syndrome is an accumulation of several disorders such as abdominal obesity, dyslipidemia, decreased blood HDL-cholesterol concentration, elevated triglycerides, hypertension and elevated fasting glucose/impaired glucose tolerance/insulin resistance. Conditions that may increase the risk of cardiovascular disease, type 2 diabetes and vascular and neurological complications.
Classification of fibers
Many of us are familiar with fibers being either soluble, which are the kind of fibers that dissolve in water, and turns into gel during digestion, and insoluble fibers, which are the ones that does not dissolve in water.
While some plants are especially rich in the soluble fibers, most of the plant foods we eat contain a combination of soluble and insoluble fiber. (6, 7)
Some sources of soluble fibers:
- Sweet potatoes and potatoes
- Apples, pears, peaches, berries, etc.
- Oats bran, amaranth, barley, etc.
- Citrus fruits
- Beans, legumes, and lentils of all kind
- Cruciferous such as brussels sprouts, broccoli, cauliflower, etc.
- Avocados
- Carrots, asparagus, etc.
- Dried figs, apricots and dates, etc.
Some sources of plants rich in insoluble fibers:
- Potato and sweet potatoes
- Nuts
- Beans, legumes, and lentils of all kind
- Berries
- Whole grains, especially barley, quinoa, oatmeal, amaranth, millet
- Coconut (flakes and flour)
- Avocado
- Turnips, spinach, radishes, rutabaga, leeks, asparagus, Jerusalem artichokes, chicory, etc.
- Almonds and walnuts
- Cocoa, etc.
Most fruits, vegetables, tubers, grains and legumes contain a mixture of both, soluble and insoluble fibers, as a result, consuming a great variety of both, soluble and insoluble fibers is an important part of a nourishing diet.
But let’s move behind the soluble/insoluble classification to a more practical division from the perspective of our health: (8)
The fermentable versus non-fermentable fiber categories
Fibers can also be classified as fermentable and non-fermentable.
The fermentable/non-fermentable fiber categories overlap with the soluble and insoluble categories…
As example, the soluble fibers are usually fermentable but also certain types of insoluble fibers are fermentable.
Fermentable versus non-fermentable fibers
Some types of fiber that are fermentable serves as food to the bacteria that reside in our large intestine. In reality, colonic bacteria thrive on fermentable fibers, and they benefit us many ways that are extremely beneficial to our health and well-being.
Fermentable fibers are divided in four types:
1- Inulin – found in garlic, onions, Jerusalem artichoke, dandelion-root, chicory-root, yacon, burdock root, etc.
2- Beta-glucans – found in mushrooms, dates, oat fiber, etc.
3- Pectins – found in fruits, especially in peaches, grapefruit, apricots, oranges, apples. Also, in veggies, especially in carrots, potatoes, tomatoes, in legumes, especially in peas, etc.
4- Resistant-starch – found in cooked and cooled potatoes, rice, legumes, especially in the lentils. Also, in green plantains, green mangos, etc.
Think about the types of fibers above as a scale moving from not fermentable at all (inulin), to the most fermentable ones (resistant starch). (9)
So, the resistant starch is the most fermentable type of fiber.
Then, let’s keep our attention in the resistant-starch fiber, particularly because this kind of fiber is extremely beneficial to restore the health of our gut-ecosystem and helpful to our overall health. (10, 11)
Then, I will continue next week the second part of this article.
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