Dietary fibers occur almost exclusively in plant foods and are largely indigestible by the body. This means that they are not decomposed in the stomach and intestines and are excreted almost undigested. This is because they cannot be broken down, or only incompletely, by the enzymes normally found in the gastrointestinal tract.
Dietary fibers have some benefits on digestion. As swelling and filling substances, they can bind water to themselves - sometimes up to 100 times their own weight. This increases the volume of stool in the intestine, stimulates intestinal peristalsis and makes the stool looser and easier to excrete.
In addition, dietary fibers also benefit gut bacteria. Some of them, the so-called prebiotics, serve as a nutritional basis for the "good" intestinal bacteria that have settled there. These can multiply particularly well if sufficient prebiotics are available.
Not all dietary fibers are automatically prebiotics. But also the fibers, which are spurned by the intestinal bacteria, are important for the intestine. Their swelling capacity fills intestines for longer, lowers the blood sugar level and thus the insulin release and stimulates intestinal movement, which leads to good and regular digestion.
Dietary fibers clean the intestines, which is one of their most important tasks. The fibers also absorb toxins and are thus excreted. In addition, they bind saturated fatty acids after a fatty meal. In this way fatty acids are excreted and not converted into body fat. At the same time, the cholesterol level remains low.
About 30 g of dietary fiber (1/4 cup) should be consumed daily. If so far the body is unused to fiber, increase the supply slow in order to accustom the intestine to it. Dietary fibers need water to spring up, therefore drink enough liquids.
Dietary fiber per 100 g of food
|Linseed, wheat bran
|20 g and more
|Peas, chickpeas, beans, celery
|Lentils, peanuts, macadamia nuts, almonds, pistachios, crispbread, artichokes
|Hazelnuts, walnuts, blueberries, black currants, raspberries, pumpernickel, wholemeal rye bread, wholemeal wheat bread
|Red currants, blackberries, Brussels sprouts, parsnips, broccoli, green cabbage, fennel, carrots, peppers
Positive properties of dietary fibers
- Prolongs feeling of fullness through swelling capacity.
- Stimulates the intestinal cells to produce "saturation" hormones.
- Must be broken down with great energy expenditure, which means additional calories are consumed.
- Keeps blood glucose levels low, which means less insulin is released, which in turn stops fat burning.
- Prevents and counteracts constipation.
- Some have a prebiotic effect and are food for healthy bacteria.
There are different types of dietary fibers, the water-insoluble ones (cellulose or lignin found in cereal or vegetable shells) and the water-soluble ones (resistant starch, pectin, inulin, oligofructose, Indian guar bean, lactulose, galactooligosaccharides, glucomannan).
Water-insoluble dietary fibrers are useful for healthy but sluggish intestines. If the intestine is damaged, however, a diet with whole grains and raw vegetables leads to increased fermentation, which can lead to digestive problems.
Water-soluble dietary fibers, on the other hand, gently stimulate digestion because they are easily soluble and therefore do not strain the intestines. They are fermented in the large intestine by the useful bifidobacteria and thus promote the growth of these good bacteria.