Dietary fiber is found only in plant foods: fruits, vegetables, nuts and grains. The amount and kind of fiber varies in different plants. Fiber includes pectin, gum, mucilage, cellulose, hemicellulose and lignin. All of these are non-starch polysaccharides.
Fiber or “dietary fiber,” is also known as “roughage.” It is the indigestible part of plant foods that cannot be digested by our digestive enzymes.
Dietary fiber is found only in plant foods like fruits, vegetables, nuts, and grains. The amount and type of fiber varies in different plants. Fiber includes pectin, gum, mucilage, cellulose, hemicellulose, and lignin. All of these are non-starch polysaccharides. Non-starch polysaccharides are important for lowering cholesterol and keeping blood sugar levels stabilized.1
Dietary fibers are classified into two main groups: soluble or insoluble. Both types of fiber are present in all plant foods, but in varied proportions.
The US FDA recommended daily fiber intake is 30-35 grams for men and 28-30 grams for women. To benefit from this amount of fiber, one must consume a huge amount of plant material which is difficult for our bodies to fully digest. Based on this understanding, the natural plant fibers have been converted to oligosaccharides which can then be taken as a dietary supplement in capsules, tablets or in other varied forms such as powder. In powder form, it can be added to a wide variety of food products like cereals, bread, cookies, beverages etc. Both soluble and insoluble fibers, or functional fibers, have been studied extensively and found to have a wide array of health benefits.
“Functional fiber” is a new term that has come into the picture recently. These fibers are isolated oligosaccharides derived from their plant sources and have now been studied for their beneficial physiological properties in animals and humans. Examples of these include fructooligosaccharides, galactooligosaccharides, inulin, arabinogalactans, xylooligosaccharides, beta-glucans, resistant starches, and gums.
Beta-glucans, derived from medicinal mushrooms and baker’s yeast, are another functional fiber gaining attention for heart health and regulating blood sugar levels.
1: Meyer, D. “Nondigestible Oligo‐ and Polysaccharides (Dietary Fiber): Their Physiology and Role in Human Health and Food.” Wiley Online Library, John Wiley & Sons, Ltd (10.1111), 20 Nov. 2006, onlinelibrary.wiley.com/doi/pdf/10.1111/j.1541-4337.2002.tb00009.x.