FIBER FACTS Fiber is the indigestible remnants of plant cells found in fruits, vegetables, whole grains, nuts, seeds, and beans, act through the digestive tract. It cannot be digested by enzymes present in the small intestine especially alpha-amylase or any other sugar-hydrolyzing enzymes in the gut. Fiber increases the elimination of waste matter in the large intestine and gives you an urge to have a bowel movement. The low fiber in the diet increases the transit time in the small and large intestine before being expelled through the colon. But high fiber diet cut down on the transit time, so food has less time to putrefy in the colon, toxin are quickly flushed out of the system. What is a dietary fiber? The following criteria used to define a fiber Is present in edible plant cells Is a carbohydrate Resists hydrolysis by human/mammalian intestinal enzymes. Resists absorption in the small intestine. Is fermented (partially/totally) by large intestinal bacteria The two different types of fibers are soluble and insoluble fibers Soluble fibers Soluble fiber dissolves in water and becomes a gelatinous form, which may help slow digestion and help our body to absorb vital nutrients.
Soluble fiber normally found in oatmeal, nuts, seeds, banana, apples, beans, strawberries, pears. Common water-soluble fibers are excellent substrates for production of short-chain fatty acids (SCFAS) in the large intestine. Short-chain fatty acids are produced in the large intestine when dietary fiber gets fermented. The Intestinal breakdown of fibers leads to the production of the substantive amount of short chain fatty acids, mostly formate, acetate, butyrate, and propionate. SCFAs have a significant role in improving gut integrity, maintaining blood glucose levels, lipid metabolism, appetite regulation and immune function. Fiber may also reduce the risk of heart disease. Short-chain fatty acids help our metabolism by affecting the mitochondria in two different ways. One, they turn on the fat-burning activity of the mitochondria and the second; they support the mitochondrial recover from inflammation and burn more fat. SCFA produced in the colon are effectively absorbed, a little of 5-10% is excreted in the faeces. Let's understand more about individual short-chain fatty acids ACETATE Mostly absorbed in the colon, 60-70 percent of the absorbed acetate is taken up by the liver, and the remainder enters the blood (systemic circulation). In the blood acetate is used by two different enzymes, acetyl-coenzyme A (CoA) synthetase in the cytosol of adipose tissue and mammary gland use this acetate for lipogenesis (synthesis of fatty acids). BUTYRATE It s an import SCFA, and considered as a preferred fuel of the intestinal epithelial cells and also plays a major role in the regulation of cell reproduction or multiplication (proliferation) and differentiation (the process by which cells undergo a change towards a more specialized form). Butyrate has been shown to inhibit nuclear factor kappa B (N.F.K.B) activation of macrophages in the lamina propria (a thin vascular layer of connective tissue under the epithelium of a mucous membrane). Butyrate is widely metabolized by erythrocytes.
Animal studies showed sodium butyrate exerts an antiproliferative (to prevent or check the spread of cancerous cells) PROPIONATE It is a substrate for hepatic (liver) gluconeogenesis (generation of glucose from non-carbohydrate carbon substances like amino acids, glycerol and lactate) and has been associated with the imbibition of cholesterol synthesis in liver tissue. Has systemic effects in human, potential hypolipidemic (decrease in the lipid levels in the blood). The ratio between propionate to acetate could be the mechanism by which propionate reduce the serum lipids. Insoluble fiber The insoluble fiber cannot be broken down by water, this type of fiber mainly found in whole grains, barley, brown rice, cereals, carrot, cucumber, and tomatoes. Insoluble fiber stays in its fibrous form, helps food pass through the digestive system and adds bulk to the stool, this helps us stay with regular bowel movements and it also provides the bulk needed for proper functioning of the gut Fiber-rich foods contain phytochemicals, which give fruits and vegetables the characteristic flavor and colour. They do possess antioxidant activity. High fiber-containing foods Chia seeds High in fiber, swells, from seven to nine times inside the stomach. Also a good source of omega-3 fatty acids, antioxidants, iron, and calcium. However, omega-3 present in chis seeds is in Alpha- linolenic acid (ALA) which may not be used as it has to be converted into active forms of Eicosapentaenoic acid (EPA) & Docosahexaenoic acid (DHA) before it can be used by the body. Hence, plant omega-3 is not highly suitable for human use as humans are not equipped to convert ALA to its active forms EPA & DHA. Animal source of fish oil is a better source of omega-3 fatty acids as compared to the plant.
Flax seeds Contains both soluble and insoluble dietary fiber. Soluble fiber slows down the digestion rate and helps in reducing the blood sugar levels and cholesterol. Whereas insoluble fiber allows more water to bind to the stools and make it soft which in turn prevent constipation. Flax seeds contain large amounts of lignans. Lignans in women help balance estrogen levels, and in men, they help in improving prostate health and maintain testosterone levels. Sesame seeds Good source of dietary fiber, contains sesame a sesamolin which are a type of lignans. Oats and wheat Oat fiber has sepsis reducing effects, whereas wheat fiber is mainly effective in cancer prevention. Proximal colon where most of the oat fibers are metabolized, whereas wheat fibers are most effective in the distal colon, this part of the colon where most of the cancers are localized. Fiber-rich fruits and vegetable Citrus fruits
Sixty to seventy percent of the dietary fiber in citrus fruit in pectin, a phytochemical found in the cell wall of plants. Found underneath the peel off an apple, grapefruits, oranges, apricots. It has a strong antioxidant activity against the three most dominating oxidant damages including by peroxyl, superoxide, and hydroxyl radicals. Both lectins and pectine are examples of components of fiber that can make a real difference in our life. Blueberries High in soluble fiber pectin, no cholesterol or fat Pears More fiber also contains antioxidants. Black, rasp and strawberries are good sources of dietary fiber Coconut Fibrous one-seeded drupe, high source of dietary fiber which helps in regular bowel movements. Reduces the risk of cardiovascular/ heart diseases and also helps in blood sugar management. How much fiber to eat A minimum daily requirement of fiber intake is in a range of 30-35 grams per day, which corresponds to approximately half a kilogram of fruits and vegetable or 5-8 fresh fruits and vegetables per day. For children above the age of two years are usually defined on age plus 5 gram/day. A three-year-old can consume a total of 8 grams/day (age 3+ daily recommended dose of 5 gram/day)
Health benefits of fiber supplementation ü Change in mucosal structures, increases the mucosal growth and improve muscle function. ü Increase intestinal flora, relieve constipation, reduce production of putrification gasses, doesn t allow the bad bacteria to enter into the intestine. ü Reduce serum triglycerides, cholesterol, very low-density lipoprotein (bad cholesterol, LDL). ü Reduce glycemic response (controls blood sugar levels) ü Improve water and electrolyte balance, increases bioavailability and absorption of minerals, such as calcium, magnesium, iron, and zinc. References Digestion (1974) 11, 289-306 Am J Clin Nutr. 1991;53(3),681 687 J of Nutrition 1999; 129, 1424S-1427S J Nutr. 2000;130(8),1991 1995 Dig Liver Dis. 2002;34, Suppl 2: S111 120 Susan S Cho and E. T. Finocchiaro, Handbook of prebiotics and probiotic ingredients - Health benefits and applications. 2010, CRC Press J Food Sci. Technol., (2012), 49 (3), 255-266 Gut Microbes 2016; 7(3), 189-200 National Institute of Health (NIH) information website