Dietary Fiber Quiz

Dietary fiber is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. It has two main components: soluble fiber and insoluble fiber. Soluble fiber is generally fermented in the colon into gases and physiologically active by-products, while insoluble fiber is inert to digestive enzymes. A diet high in regular fiber consumption is generally associated with supporting health and lowering the risk of several diseases. Food sources of dietary fiber include legumes, whole grains and cereals, vegetables, fruits, and nuts or seeds. Bulking fibers, viscous fibers, and fermentable fibers all have different effects on the gastrointestinal system. Soluble fibers such as beta-glucans from oats or barley have been established to lower blood levels of LDL cholesterol. Insoluble fiber is associated with reduced risk of diabetes, but the mechanism by which this is achieved is unknown. Dietary fiber has importance in the diet, with regulatory authorities in many developed countries recommending increases in fiber intake. Adding viscous polysaccharides to carbohydrate meals can reduce post-prandial blood glucose concentrations. The effects of dietary fiber in the colon are on the absorption of nutrients, production of short-chain fatty acids, and the size and metabolic activity of the gut microbiota.Dietary Fiber: Its Health Benefits, Effects, and Recommendations

• Certain non-absorbed carbohydrates can be fermented into short-chain fatty acids (SCFA) in the colon, which can be absorbed by the colonic mucosa. Butyric acid is the preferred energy source for colonic cells.
• Dietary fiber can affect cholesterol metabolism by reducing the reabsorption of bile acids in the ileum, which has several direct effects.
• Fecal weight is dictated by water distribution in the colon and the amount of fiber consumed.
• Fiber can affect health through mechanisms such as reducing the risk of several cancers, cardiovascular diseases, and type II diabetes.
• Fiber does not bind to minerals and vitamins and may even improve their absorption.
• The European Food Safety Authority recommends 25 grams of dietary fiber per day for normal laxation in adults.
• The United States National Academy of Medicine recommends 38 grams of dietary fiber per day for adult men ages 19–50, 30 grams for men 51 and older, 25 grams for women ages 19–50, and 21 grams for women 51 and older.
• North Americans consume less than 50% of the recommended dietary fiber levels for good health.
• The British Nutrition Foundation recommends a daily minimum intake of 30 grams of dietary fiber for healthy adults.
• Soluble fiber is defined by the American Association of Cereal Chemists as "the edible parts of plants or similar carbohydrates resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine."
• Fermentable fiber can be changed into short-chain fatty acids (SCFA) in the colon, which are involved in numerous physiological processes promoting health.
• The FDA allows manufacturers of foods containing specific amounts of psyllium husk, oat or barley soluble fiber to claim that regular consumption may reduce the risk of heart disease.