Edited by Veronica Pacella, Nutritionist
The fibers are a complex of substances contained in foods of vegetable origin such as fruits and vegetables, classified in non-soluble fibers, soluble fibers and lignans, useful for balancing the intestinal flora and lowering the level of cholesterol in the blood. Let's find out better.
Jerusalem artichoke among foods rich in vegetable fibers
What they are for and where the fibers are
Most cereals and vegetables contain insoluble fiber, insoluble in water but capable of binding to it, which is why, once ingested, it has the effect of increasing the size and weight of faeces. The insoluble fiber is mainly represented by the cellulose, fermented by the intestinal bacterial flora with the production of short chain fatty acids, of which the cells of the intestine are nourished.
Soluble, water-soluble fibers include:
- hemicellulose : present in bran, they promote bowel movements, increasing stool hydration, binding to cholesterol and avoiding absorption;
- gums and mucilage : present in the seeds of plants such as cereals, legumes, nuts and oilseeds. They reduce the levels of glucose and insulin, reduce cholesterol, decrease the sense of hunger and promote weight loss, are laxatives and some of them are used by the food industry as thickeners and stabilizers;
- pectins : they are found on the walls of plant cells and in the peel of fruit. Among their properties there is that of forming a gel responsible for reducing cholesterol and used on an industrial level for cakes and jams.
- polysaccharides of algae: used in the food industry as thickeners, emulsifiers and binders.
Lignans are composed of important anticancer, antibacterial, antifungal and antiviral properties. They are transformed by the intestinal bacterial flora into enterolactone and enterodiol, compounds that protect from cancer. Flax seeds, whole wheat, walnuts and legumes are rich.
The fibers also contain Inositol, Fruit-oligosaccharides and Galacto-oligosaccharides, also known as prebiotics
You can learn more about which foods are more rich in fiber
The properties and benefits of fibers
The beneficial effects of the whole fibers are above all:
- decreased intestinal transit time
- slowing of gastric emptying with reduction of blood sugar levels after a meal
- increased feeling of satiety
- increase in pancreatic function
- increased stool weight
- increase in beneficial intestinal microflora
- increased short chain fatty acid production
- decreased cholesterol and triglyceride levels in the blood
- more soluble bile
The effects of fiber deficiency
A lack of fiber leads to gastrointestinal disorders and colon diseases (diverticulitis, irritable bowel syndrome, ulcerative colitis, appendicitis, hemorrhoids, hiatal hernia), heart disease (for cholesterol and triglycerides), obesity and type 2 diabetes.
The only contraindications of the fibers concern the presence of acute gastritis or disorders such as irritable bowel syndrome, in which an excess of fibers could aggravate the symptoms.