What is dietary fiber?
The term “dietary fiber” comes from a time when these food ingredients have been considered as “superfluous ballast”.
The fiber is mostly carbohydrates. It used to be thought that dietary fiber was not usable by the human body because human digestive juices contain no enzymes that can break down these compounds. It has been overlooked that some of the dietary fiber is fermented by enzymes of the microorganisms of the large intestine. In addition to gases, short-chain fatty acids, which can be utilized by humans, are also produced. The energy gain from dietary fiber (2-3 kcal / g) is negligible due to the low amounts added. The intake recommendation of the DGE of 30 g fiber per day is often not reached.
The fibers include cellulose, hemicellulose, pectin, agar-agar, lignin, etc.
One distinguishes between insoluble and soluble fiber.
The insoluble fiber can increase its volume thanks to its high swelling capacity. That is, they bind fluid, thereby increasing the volume of the intestinal contents, which in turn accelerates the natural intestinal movement and reduces the residence time of the chyme in the intestine. Ingested in sufficient quantities, they can prevent widespread constipation.
The soluble fiber binds bile acids (which consist of 80 percent cholesterol) and other metabolic products and ensures their elimination. In this way, less cholesterol gets into the blood and the cholesterol level drops.
All fiber, except lignin, can bind water. In the so-called swelling substances, the water binding can be up to 100 times its own weight.
Effect of dietary fiber:
The positive effect of fiber
- Lasting satiety
- Binding and removal of cholesterol and bile acid, thereby lowering cholesterol levels.
- Increase in colonic mobility (mobility)
- Water retention in the colon, which contributes to a supple chair.
- Prevention of a number of chronic bowel diseases.
- Possibly reducing the colorectal cancer risk
The negative effect of dietary fiber
- Flatulence due to gas formation of microorganisms
- Additional contamination with xenobiotics
- Direct epithelial damage (intestinal mucosal tissue)
- Binding of calcium, magnesium, iron and zinc, which reduces their absorption rate.
- Intestinal entanglement due to excessive colon filling.
Fiber in food:
Dietary fiber is found only in vegetable products, especially whole grains, legumes, vegetables, salads, sprouts, and fruit.
Fiber in 100g food:
- Oatmeal: 10 g
- Wheat Germ: 17.7 g
- Wheat bran: 45.4 g
- Rice: 4.5 g
- Crispbread: 14 g
- Peas: 16.6 g
- Corn: 9.7 g
- Lentils: 17 g
- Soybeans: 21.9 g
- Beans, white: 23.2 g
- Kale: 4.2 g
- Cauliflower: 26.3 g
- Carrots: 12.1 g
- Prunes, dried: 5.0 g
- Whole wheat pasta: 8.0 g
- Whole wheat bread: 8.3 g