A diet containing the essential nutrients with a reasonable ratio of all the major food groups. The quantity of foods required to get a balanced diet may vary with age, gender, physiological status and physical activity. Our human system essentially requires macronutrients like carbohydrates, proteins and fats to avail the balanced diet. These macronutrients primarily supports, promotes and maintains overall well-being and good health. However, in addition to the macronutrients,a balanced diet may also include dietary fiber, antioxidants and phytochemicals.
Fiber is classified under the category of carbohydrate which is considered to be an essential nutrient. Fiber chemically constitutes non-starch polysaccharides. Fiber is naturally present in plants and functional derivatives are Cellulose, Resistant Dextrins, Hemicellulose, Oligosaccharides, Resistant Starch, Chitins, Pectins, Beta-Glucans and Lignin. Generally, most of the carbohydrates are broken down into sugar molecules by various enzymatic hydrolysis in human system, whereas,the fibers considered not to be completely broken down into digestible sugar molecules in the small intestine (for the reason, humans lack the necessary enzymes to split the glycosidic bond which is present in the fiber). Therefore, undigested fiber passes through the large intestine, where it is fermented by bacteria. The by-products of this fermentation are carbon dioxide, methane, hydrogen and short-chain fatty acids (SCFA’s). It should be noted that, increase in the amount of fiber or depending on the type of fiber or intake above the prescribed or approved limits of fiber may cause an increase in gas production which leads bloating.
Fiber is classified as Soluble Fiber and Insoluble Fiber.
• Soluble fiber:
It is fiber which readily dissolves in liquids. Some types of soluble fiber provide viscosity and it is hydrophilic to form a gel-like substance in the gastrointestinal tract during the digestion process. While other types of soluble fibers are not viscous by nature, but are fermented instead providing several physiological benefits.
Soluble fiber increases the stool bulk and at the same time softens it so that it slides easily through the large intestine.
Soluble fibers are present in apples, oranges, grapes, dry beans, lentils, peas, barley, oats and the likes thereof.
• Insoluble fiber: It is the type of fiber which does not readily dissolve in liquids and remains relatively unchanged in the gastrointestinal tract during the digestion process. Insoluble fiber prevents constipation by adding bulk to fecal content in the large intestine. Generally, insoluble fiber is minimally fermented. Insoluble fibers are present in vegetables, whole grain products, whole wheat bread, bran, pasta, crackers, edible seeds, brown rice and the likes thereof.
Based on American Heart Association Eating Plan, total dietary fiber intake should be 25 to 30 grams a day from food. Currently, dietary fiber intake among adults in the United States averages about 15 grams a day. That's about half the recommended amount. Also, from literature, recommended fiber intake for Asian Indian adults is 21 to 38 grams daily.
The dietary fibers of selected foods are provided below. The portion, intake, size of the food to be consumed is based on the individual characteristics and based on country-specific guidelines.
Fiber is complex carbohydrate which is not digested in the small intestine. Fibers generally comes from the plant source. It is found in a wide variety of foods. Based on the mechanism, the three predominant forms of fiber includes bulking, viscosity, and fermentation. As a bulking agent, it helps to decrease constipation and reduce the risk of gastrointestinal tract infection, specifically the disease or disorder associated with the colon. As a viscous fiber, it helps to decrease the absorption of lipoproteins and other forms of cholesterol by thickening the gastrointestinal tract. Also, in gut or intestine, the dietary fiber enhances the good bacteria based on fermentation. Bulking As said hereinabove, fibers decrease constipation and reduce the risk of gastrointestinal tract infection, specifically the disease or disorder associated with the colon. In intestine or colon, fibers absorb or imbibe water, which leads to the formation of bulkiness and promotes the regularity of normal intestinal functions. There are the wide variety of plant sources, pulses and cereals and legumes available in wide range to act as bulking agents. Specifically, Wheat Bran, Cellulose and Psyllium act as bulking fiber. Viscosity As said hereinabove, viscous fibers decrease the absorption of lipoproteins, other forms of cholesterol and nutrients by thickening the content of gastrointestinal tract. These actions may slow down the movement of essential and non-essential nutrients into the gastrointestinal tract walls. The advantage also includes reducing or lowering the cholesterol levels in the blood and in turn decreasing the glycemic response or blood sugar levels. The viscosity of the fiber is directly proportional to the effectiveness in reducing absorption. There are the wide variety of plant sources, pulses and cereals and legumes are available in wide range to act as bulking agents. Specifically, Beta-Glucan, Guar Gum and Psyllium acts as viscous fiber. Fermentation According to sources, it is reported that trillions of bacteria live in the healthy human gastrointestinal tract, specifically in the digestive tract which plays a vital role in human health and well-being. Colonization of bacteria in the colon is widely grown and dietary fibers play a vital role in feeding the microflora which is important for guts. The bacteria present in the colon interfere with fibers through a process of fermentation and produce the short chain fatty acids (SCFAs). The SCFAs have multiple beneficial effects in maintaining the colon and also the gut system. It increases the bowel regularity by peristalsis movement. The SCFAs triggers various biochemical pathways which are assumed to provide a wide range of health benefits, also the SCFAs have a vital role in the absorption of essential minerals such as calcium and magnesium.
Nature provides the support for humans to intake dietary fibers in the form of fruits, vegetables, whole grains, and legumes which supports for normal well-being. Mainly, dietary fibers are indicated for supporting the gut/digestive system. However, consuming fibers have enormous benefits. Consumption of fibers develops the immunity in the gut, produces beneficial probiotics and pulls out the excess amount of cholesterol or fat and other toxins from the human system. Literature also supports that, increasing fiber intake decreases the risks of common disorders such as cardiovascular disease, cancer, diabetes / control of blood sugar, skin health and weight management/obesity.
As said hereinabove, fibers has numerous beneficial properties to support the well-being of humans. Below are few reported and emerging evidence which supports potential benefits of dietary fibers in humans,