Dietary fiber is a plant-based nutrient and a type of carbohydrate, unlike other carbs, it cannot be broken down by the human digestive system into digestible sugar molecules. Fiber passes through the intestinal tract relatively intact.
Fiber is important to digestion and regularity, weight management, blood sugar, cholesterol maintenance and it is linked to longevity and decreasing the risk of diseases.
Fiber can be put into two categories: soluble and insoluble fiber. Plant-based foods contain both soluble and insoluble fiber. Soluble fiber, such as pectin, gum, and mucilage, dissolves in water; insoluble fiber, such as cellulose and lignin, do not. In the body, soluble fiber dissolves and becomes a gel-like substance. Insoluble fiber mostly retains its shape while in the body.
Soluble fiber helps to decrease blood glucose (blood sugar) levels. It also helps lower blood cholesterol. Insoluble fiber speeds up the passage of food through the digestive system. This helps maintain regularity and prevent constipation. It also increases fecal bulk, which makes stools easier to pass.
The difference is found in the chemical structure (open or closed) which makes the fiber solvable or not. Fibers do play an important role in relation to function in age control. Fiber-rich diets show to give a better control of the gut flora. This gut flora is one of the first parts of the body which degenerate while aging. In current knowledge, it is not yet established how it happens but the first part of aging starts with a malfunctioning of digestion intake. When building materials (the mentioned other food parts) are not digestively prepared for uptake the body is no longer able to recover and restore damaged tissues, nor has the energy to fight diseases. This is the main area fibers are active. in.
The effects of fibers on health are;
Resistant starch and glucose metabolism
There is good evidence that postprandial glycemic responses to RS are reduced compared to digestible carbohydrates. As such, there is an approved health claim in the EU stating that baked products containing at least 14% RS in place of digestible starch reduce postprandial glycemia. There may be synergism between RS and other fiber types in reducing glycemic responses.
Different types of fibers for human consumption
|Cellulose||E 460||cereals, fruit, vegetables (in all plants in general)|
|Chitin||—||in fungi, the exoskeleton of insects and crustaceans|
|Hemicellulose||cereals, bran, timber, legumes|
|Lignin||—||stones of fruits, vegetables (filaments of the garden bean), cereals|
|Xanthan gum||E 415||production with Xanthomonas-bacteria from sugar substrates|
|Resistant Starch||Can be starch protected by seed or shell (type RS1), granular starch (type RS2) or retrograded starch (type RS3)|
|Resistant Starch||—||high amylose corn, barley, high amylose wheat, legumes, raw bananas, cooked and cooled potatoes etc.|
|water-soluble dietary fibers|
|Arabinoxylan (a hemicellulose)||—||psyllium|
|Fructans||replace or complement in some plant taxa the starch as a storage carbohydrate|
|Inulin||—||in diverse plants, e.g. topinambour, chicory, etc.|
|Pectin||E 440||in the fruit skin (mainly apples, quinces), vegetables|
|Alginic acids (Alginates)||E 400–E 407||in Algae|
|Sodium alginate||E 401|
|Potassium alginate||E 402|
|Ammonium alginate||E 403|
|Calcium alginate||E 404|
|Propylene glycol alginate (PGA)||E 405|
|carrageen||E 407||red algae|
|Polydextrose||E 1200||synthetic polymer, ca. 1kcal/g|
Conclusion; Fibers do have a wide range of functions in the body. It must be clear that there is a distinction between pure carbohydrate constructed fibers and fiber networks made of proteins when we define the right group of fibers.