But what makes fiber so special and how does it work? Dietary fiber is an indigestible component of plant foods. High-fiber foods include whole grains, legumes, apples, bananas, lettuce, nuts, or dried fruit.
100 g of potatoes contain approx. 2 g, a banana 4 g, and with two slices of wholemeal bread you already consume 10 g of fiber.
The enzymes in our small intestine are not able to utilize dietary fiber, which is why they are not directly involved in the metabolism. In the large intestine, however, colonize bacteria that are able to ferment fiber, i.e. break it down and make it digestible for humans.
- Dietary fibers with a low water-binding capacity such as cellulose or lignin, which are hardly broken down by bacteria
- Dietary fibers with a high water-binding capacity such as pectin, guar or ß-glucan which are completely fermented by the aerobic intestinal flora and can therefore also be used by the human body.
How does fiber work
Help with constipation
The water-binding capacity of dietary fiber is understood to be its ability to absorb water and consequently to swell – one of the most important characteristics of these food components. This increases the intestinal volume, the intestine expands and digestive activity is stimulated, which is particularly helpful in the case of constipation. Dietary fiber can bind many times its own weight to water, so it is extremely important to take in enough fluids at the same time (ideally in the form of water or unsweetened tea).
Preventive against coronary heart disease
At the same time, water-soluble fiber binds bile acids and makes a significant contribution to lowering the cholesterol level. Daily consumption of approx. 30g of fiber can reduce the cholesterol level by 5-10%, which is important in the prevention of coronary heart disease, the most common cause of death in industrialized countries.
Protection against colon cancer
Fiber can also help prevent colon cancer. By increasing the stool volume and shortening the transit time, it is more difficult for carcinogens, i.e. carcinogenic substances, to come into long-term contact with the intestine and thus develop their negative effects.
According to the EPIC study, the risk of developing colon cancer is 40% lower if you increase your fiber intake from 15 g daily to 35 g. The EPIC study is a study that began in 1992 and investigates the connection between diet and cancer at the European level. 520,000 people from 10 European countries are involved in it.
Prevention of type 2 diabetes mellitus
Another asset of these food components, which are extremely beneficial for the human body: Due to delayed starch digestion and glucose absorption, the blood sugar level rises more slowly after eating high-fiber foods. This protects against blood sugar peaks and thus also against the development of type 2 diabetes mellitus.
Good for your teeth
Dietary fibers develop their positive effects in the mouth. Long chewing of high-fiber foods and the resulting increased production of saliva has a positive effect on dental health.
The German Society for Nutrition recommends consuming 30 grams of fiber per day.