Fiber
Dietary fiber and foods rich in dietary fiber
Introduction
Dietary fiber has been used for centuries, and today supermarkets label their dietary fiber content. Although fiber is not considered a specific food, health professionals and nutritionists agree that adequate amounts of fiber are necessary for the proper functioning of the gastrointestinal tract. Dietary fiber is vegetable food or food containing carbohydrates, which cannot be digested or absorbed in the human small intestine, i.e. it is completely resistant and partially fermented in the large intestine. Reduction of LDL-cholesterol, regulation of insulin levels in the blood, improvement of gastric function are associated with intake of dietary fiber, products consumed by people, which are rich in fiber components, for example, vegetables, fruits, grains and nuts. The basis for dietary fiber consumption was based on epidemiological studies of high-fiber foods, which reduced the risk of nutrition-related diseases in the United States. Specifically, obesity, coronary disease, diabetes, gastrointestinal disorders including constipation, inflammatory bowel diseases such as diverticulitis, ulcerative colitis and colon cancer.
Although dietary fiber is beneficial for health and is associated with reduced risk of many diseases, consumption levels remain low in many parts of the world, particularly in the United States. Food biotechnologists use high-fiber ingredients to produce not only a high-fiber food supply, but also to improve the taste of high-fiber products, which will encourage continued consumption of these types of products.
Classification based on solubility
According to their ability to dissolve, dietary fiber is classified into two types - soluble and insoluble dietary fiber.Soluble fibers dissolve in water and include resins, mucilage, pectin, and some hemicelluloses. These fibers are found in all types of peas, lentils, almost all types of beans, oats, barley, vegetables (carrots) and some fruits such as apples, oranges. Psyllium seed is also included in this group.
People with diabetes should eat foods that contain soluble dietary fiber, which helps to lower and control blood sugar levels and also reduce the need for insulin. Studies have shown that beans, oats, psyllium, or other sources of soluble dietary fiber help lower fasting blood sugar levels and help lower blood cholesterol levels, especially LDL-cholesterol. "bad" cholesterol. Fiber lowers blood cholesterol by "trapping" bile acids, which are produced from cholesterol, transported through the digestive tract, and then excreted from the body as waste. Soluble fiber in beans, psyllium fiber, and oat fiber have also been found by researchers to lower blood cholesterol levels.
Insoluble fibers do not dissolve in water. Cellulose, lignin and part of hemicellulose belong to the type of insoluble fibers. These are the fibers that determine the structure of plants. All grains, wheat and grain fiber, many types of vegetables including cauliflower, green beans, potatoes are very good sources of insoluble dietary fiber. Vegetables and fruit skins are also very good sources of insoluble fiber. Wheat bran is also a rich source of insoluble dietary fiber, which is why it is added to many morning dry wheat breakfasts. Insoluble fiber is also known as "rough food", which helps the digestion process in the form of water retention in the intestine, which leads to a soft fecal mass and thus contributes to the normal functioning of the stomach, for example, bran contains a large amount, which ensures the prevention of some gastrointestinal diseases: diverticulosis and hemorrhoids .
Physiological functions of dietary fiber
Tumor dietary fiber
Intestinal cancer is one of the most common diseases in almost every country that causes death. On the basis of historical observations and epidemiological studies, the preventive role of fruits and vegetables rich in dietary fiber has been established in intestinal cancer. It should also be said that the anti-carcinogenic role of fermentable dietary fibers is still not well understood, although it is possible that all or some of them are involved in the chain of anti-tumor metabolic reactions.
Dietary fiber and carbohydrate metabolism
If the food contains well-fermentable viscous fibers, as food additives, it has been found that this has the greatest health benefits, reducing the glycemic response and increasing the amount of insulin, i.e. preventing diabetes. Epidemiologists have found that foods with a high glycemic index and glycemic load increase the risk of diabetes.
Dietary fibers, lipid metabolism, cardiovascular diseases
Total blood cholesterol and LDL cholesterol are used as biomarkers as potential risk factors for diseases. Experimental studies have shown that the reduction of blood cholesterol is achieved by means of well-fermentable food fibers. Therefore, they have a preventive role in cardiovascular diseases. According to a study conducted by scientists in 1998, low glucose and insulin levels were determined as a result of taking inulin. during which there is an increase in lipid metabolism, an increase in the secretion of intestinal hormones that regulate the level of insulin.
Dietary fiber, mineral biocompatibility and skeletal health
Dietary fiber in fruits and vegetables has the ability to absorb and retain some minerals. Well-fermentable dietary fibers are considered as inducers of the absorption process during metabolism. Inulin and fructooligosaccharides help the absorption of minerals in the intestine.
Dietary fiber, nitrogen utilization and bile acid metabolism
Dietary fiber also affects nitrogen balance. Fibers act as a substrate for increased microbial mass, which utilize fecal nitrogen, i.e. contribute to nitrogen accumulation and retention.
Dietary fiber and gastrointestinal disorders
The normal functioning of the large intestine and the microflora present in it determine the healthy state of the gastrointestinal system. Fermentation products of dietary fiber are important to protect the colon wall and repair damaged intestines. They also act as a barrier to prevent the entry of harmful substances and microbes in food, that is, they are one of the important components of the immune system.
Disruption of this barrier may be due to the following factors. Stress, hunger and some clinical cases when the intestine is damaged. It has been confirmed by researchers that e.g. Inulin promotes the growth of useful and necessary microorganisms for health and reduces to a minimum level the process of reproduction of pathogens and products formed as a result of protein degradation, such as: ammonium, phenolic products, amines. which in many cases cause various types of tumors and ulcerative colitis. When the intestine loses its barrier function, a chronic inflammatory process appears.
Non-fermentable dietary fibers e.g. Cellulose participates in the process of mucus formation in the intestine, which protects the intestinal walls from enzymes and toxins. They are also a food source for microorganisms.
Resistant (resistant) starch
Resistant starch stimulates the growth of health-promoting microorganisms such as lactobacilli and bifidobacteria. Their role has also been proven in blood sugar and cholesterol control and weight control. Fermentation of resistant starch produces butyric acid, which has a barrier function.
Useful dietary fiber
Cereal products, fruits, vegetables. Contains very little fat, rich source of dietary fiber.
oats and barley
Contains a large amount of dietary fiber. Oat yogurts are produced from it, as a functional food, as well as oat drinks. Oats contain beta glucan.
