Fiber

Fiber

Fiber is in a separate category, although it is a type of complex carbohydrate.  Fiber does not supply energy of heat to the body.  It is the tough, stringy part of vegetables and grains.  Fiber is not absorbed by the body, but it serves these important digestive functions:

1.      Increasing and softening the bulk of the stool, thus promoting normal defacation

2.      Absorbing organic wastes and toxins in the body so that they can be expelled

3.      Decreasing the rate of carbohydrate breakdown and absorption

Therapeutically, fiber can help treat and prevent constipation, hemorrhoids, diverticular disease, and irritable bowel syndrome.  It is linked to reduced blood cholesterol level, reduction of gallstone formation, control of diabetes, and reduction in the risk of certain types of cancer and other diseases.  Too little fiber can result in an increased risk of colon cancer, hypercholesterolemia (high blood cholesterol), and increased blood glucose levels after eating.   Too much fiber can cause constipation, diarrhea, and other gastrointestinal disorders and can impair mineral absorption. 

The recommended amount of fiber for adults is 20 to 35 grams a day.  Because fiber works in conjunction with other substances and nutrients, it is advisable to get dietary fiber from a variety of food sources (Figure 49-4).  Adequate water intake is especially important for fiber to work properly.

Fiber can be classified as soluble or insoluble.  Soluble fiber, found in foods such as oats, dry beans, barley, and some fruits and vegetables, is the type that tends to absorb fluid and swell when eaten.  It slows the absorption of food from the digestive tract, helps control the blood sugar level of diabetics, lowers blood cholesterol levels, and softens and increases the bulk of stools.  Insoluble fiber, found in the bran in whole wheat bread and brown rice, for example, promotes regular bowel movements by contributing to stool bulk.

Figure 49-4  Dietary fiber serves many functions in the human body and is considered a basic food component.

Copy typed by Shirley-Ann Pearman

Book:  Medical Assisting – Administrative and Clinical Procedures – Including Anatomy and Physiology by Booth Whicker Wyman Pugh Thompson (Third Edition)

Chapter 49 – Nutrition and Special Diets