Fibres!

What is fibre?

Fibre is that part of plant food that passes through our digestive systems without being broken down and is not digested. That is, it cannot pass into the bloodstream. They belong to the carbohydrate family but have almost no calories.

We find them in plant cell walls (e.g. cellulose, lignin, gum, pectin) and not

and are not digested by human intestinal enzymes. Their purpose is to add bulk to the diet consumed, absorb water in the intestine and produce softer and larger stools that are quickly passed.

Fibre forms a gel inside the gut, soluble and insoluble, and the body needs it because it balances insulin. After all, glucose absorption is gradual in the blood, and the liver does not need to increase insulin which is important metabolically to keep the body in a stable energy balance.

How is fibre beneficial?

When people think of the benefits of fibre, they usually think of the advantage of preventing constipation. Fibre indeed accumulates in the stools, and retaining fluids increases the volume of the stools, thus improving defecation by creating a regularity in the elimination system.

Fibre has other benefits, some relevant to low-carb diets, including reducing the effects of sugars and starches on blood glucose. A high-fibre diet is associated with a lower risk of heart disease, type 2 diabetes, and diverticular disease. Fibres are classified into two categories (according to their solubility in water):

Soluble Fibers

Those that either dissolve or swell in water are metabolized by bacterial fermentation in the large intestine (pectins, gums, mucilages around and inside plant cells). The importance of insoluble fibre is recognized, mainly in that it contributes to the good functioning of the intestine, promoting the growth of the microbial flora of the intestine.

They also tend to stabilize blood glucose, thus allowing better absorption of nutrients. Their action is further enhanced by increased water consumption, thus increasing the volume in the stools, causing a smoother movement of the intestines, thus allowing a gentler and easier passage by acting against constipation and preventing bowel cancer. At the same time, they can reduce the likelihood of diverticulitis and haemorrhoids.

Soluble fibres are considered:

• Fructo-oligosaccharides

• Pectins

• The β-glucans

• Comi guar

• The inulin

• The flea

It is indicated that soluble fibres are found in a more significant percentage of fruits, vegetables, legumes (beans, lentils, chickpeas), barley, oats, flax and psyllium, which is the natural remedy for constipation.

Ιnsoluble

Insoluble fibre is not soluble in water. They are not metabolized by bacteria in the large intestine (cellulose-structural part of plants, hemicellulose or plant threads similar to bran and lignins), reaching the large intestine almost intact, causing stool swelling. In this way, their passage is accelerated, thus increasing intestinal motility.

They prevent the creation of constipation and its unpleasant consequences, such as haemorrhoids. Research has linked them to a reduced risk of diabetes and improved insulin sensitivity, as they also appear to affect carbohydrate metabolism.

Insoluble fibres are:

• Cellulose

• The lignin

• The resistant starch

• Chitin

Insoluble fibre is mainly found in the whole grain family, and vegetables such as cauliflower, green beans, sweet potatoes, zucchini, carrots, dark leafy greens, and leafy greens are good sources of insoluble fibre, with the highest percentage them to be found in wheat and corn.

Fermentable Fibre

Some fibres are fermented in the colon, producing compounds that help support colon health and may have other benefits. Evidence shows that this type of fibre may reduce the risk of colon cancer.

Most soluble fibres have excellent ferments. Pectins (found in apples and berries) and fibre in oats are fibre with significant fermentation components. Inulin and oligo-fructose are also highly fermentable, as is resistant starch.

Fibre andhealth

Both soluble and insoluble fibre is essential for good health, so most scientific studies look at total fibre intake.

The plant fibres consumed by the body, combined with the enzymes combined during the chewing of food, reach the large intestine and, with the mediation of the intestinal flora, undergo partial or total fermentation by the intestinal bacteria. Fermentation produces various by-products, short-chain fatty acids, and gases that are produced during the fermentation of fibre by gut bacteria.

They are an important energy source for colon cells and could prevent the growth and proliferation of cancer cells in the intestine. By improving bowel function, fibre can reduce the risk of diseases and disorders, such as diverticulosis or haemorrhoids, and may also help prevent colon cancer.

The resulting short-chain free fatty acids are mainly butyric acid, propionic acid and acetic acid, and respectively the gases are hydrogen (H2), methane (CH4) and carbon dioxide (CO2). These gases are removed through the lungs or the gastrointestinal tract and are perceived by the body as a feeling of bloating.

Short-chain free fatty acids are quantitatively the primary metabolites, are rapidly absorbed from the large intestine and simultaneously stimulate sodium and water absorption. Colonic epithelial cells metabolize short-chain free fatty acids, especially butyric acid, which is considered the primary substrate for energy production and is the preferred fuel of intestinal cells. In this way, they also regulate the proliferation of colon cells.

As for the other two fatty acids, propionic and acetic acid, once absorbed, they pass through the portal vein to the liver, where they are used as fuel. Acetate mainly gives more freedom to the peripheral tissues, where the muscles metabolize it.

To conclude the fibre chapter, you don't need to worry too much about what kind of fibre you get from your diet unless you seek a specific health benefit, such as reducing cholesterol. Just focus on eating a healthy diet rich in fruits, vegetables, whole grains, legumes, nuts and seeds.