Fiber can be found in a plant’s cell wall and acts like a skeleton in order for the plant to maintain its structure and shape. When taken in by the body, these fibers remain undigested because enzymes in the body are unable to digest it. Instead, fiber just passes through the intestines. Fiber adds mass to the stool, making waste elimination easier and thus keeps the colon healthy.
Types of Fibers
There are two types of fiber: soluble and insoluble. Insoluble fibers do not dissolve in liquids, even in water. This is advantageous because the fiber then helps move matter faster through the large intestines. Insoluble fibers are especially helpful in people who have constipation or have irregular bowel movements. Also, regular consumption of insoluble fibers can also lower the risk for developing diabetes.
Soluble fibers are also called beta-glucans. Beta-glucan binds to the acids in the bile that has cholesterol. Thus, regular consumption of foods that have soluble fiber can significantly lower the amount of cholesterol in the body.
Fibers have hemicellulose, cellulose, pectin, lignin, gums, chitin, resistant starches and beta-glucans. Hemicellulose can be found in the cell wall of a plant and may be composed of several sugars. Hemicellulose can be soluble or insoluble while cellulose is purely insoluble. These are also found on plants’ cell walls.
Lignin is a kind of fiber that is water insoluble. It also cannot be digested by good bacteria. While lignin is insoluble, pectin is the opposite, as it is soluble in water and is able to be fermented by good bacteria in the body. As a result, very little pectin passes through the large intestine.
Chitin is like cellulose, the only difference is that amino acids are attached to it. Aside from plants, this fiber can also be found in crustacean shells and insect exoskeletons. Gums are water-soluble and are oftentimes used in processing food as a thickening or gelling agent. Beta-glucans are water-soluble fibers and help lower the amount of cholesterol in the body. Resistant starches are considered to be a kind of fiber than as a starch because amylase, an enzyme that breaks down starches, does not work with this compound.
Sources of Fiber in Food
Brans, nuts, roots and apple skins are good sources of cellulose. Hemicellulose can also be found in brans, legumes, nuts and whole grains. Lignin can be found in vegetables, berry seeds and root vegetables. Pectin can be found in apples, nuts, legumes and citrusy fruits. Beta-glucans can be found in barley and oats. It is sometimes added to food to serve as a functional fiber.