Dietary Fibers

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• Summary
• Where does fiber come from?
• How to choose a fiber rich diet
• Good sources include
• Functions of dietary fiber
• Health benefits from eating fiber
• Health Tips

SUMMARY

     Fiber is any edible food material that passes through the intestinal tract undigested.   In many ways the consumption of fiber  helps to maintain proper health of the digestive system.   There are three recognized forms of dietary fiber.   These forms include (1) insoluble fibers, which do not dissolve in water and are not digested at all, (2) soluble fibers which tend to dissolve or swell when in water or which can be metabolized by the bacterial microflora in the large intestine, and (3) crude fiber which is the indigestible portion of plant based foods.   It really can't be described as a single substance.   Rather, it is a group of substances related only in terms of characteristics. 

Where does fiber come from?

     Fiber is found only in plant based foods such as beans, whole-grain breads and cereals, and other vegetables and fruits.  To get different types of fiber it is best to eat a variety of fiber containing plant foods.   Routine practice of these dietary considerations is important for proper bowel function, it can help to ameliorate chronic constipation, diverticulitis, and hemorrhoids.    There is epidemiolgical evidence that fiber may also be helpful in lowering the risk for coronary heart disease and some cancers.   At this point it may be worth mentioning that since these many substances in common plants that we eat (i.e.- broccoli, etc.) have not been well characterized, the possibility exists that some of these beneficial effects may be attributed to other components of the plants being consumed.   Fibers originate in plants where they perform many structural tasks necessary for the survival of the plant.   In the case of insoluble fibers like cellulose, hemicellulose or lignons they form structures required for the plant to maintain its shape.   Cotton for instance is almost entirely comprised of cellulose.   This is a good example of such a structural fiber because of its elastic nature and ability to retain and even spring back to its original shape even when squashed.   Soluble fibers on the other hand are located around and inside of plant cells.

How to choose a fiber rich diet

          Choose a diet with plenty of grain products, vegetables, and fruits.   These foods are crucial components of a healthy diet and aside from being excellent sources of vitamins, minerals, and carbohydrates they are also quite rich in fiber.  Depending upon how these foods are prepared they have the added benefit of being low in fat.   In general, we tend to eat fewer than the recommended number of servings of grain products, vegetables, and (see food guide pyramid), even though its generally regarded that by eating these foods as recommended we can reduce the risk for acquiring numerous chronic diseases like diverticulitis and colon cancer.   The bulk of your diet should derive from grain products, vegetables, and fruits

Good sources include:

• Complex carbohydrates:  breads, cereals, pasta, rice
• Dry beans: pinto navy, kidney, black beans, etc.
• Fruits: berries, etc.
• Vegetables: potatoes, corn, etc

Functions of Dietary Fiber

     There are many reasons why we need to eat fiber.   First of all, dietary fibers help to eliminate stool from the body by allowing it to absorb water .   This the size and makes it softer and thus easier to pass.  The presence of larger stool induces a physiological response which causes rhythmic contractions called 'peristalsis' which is the mechanism responsible moving food along the alimentary canal.    Conversely, a lack of sufficient quantities of fiber will result in smaller stool and may lead to constipation.   When constipation occurs more pressure is required to move the stool along the intestine and this pressure can lead to hemorrhoids and diverticula from excessive straining.

Insoluble fiber

• Insoluble fiber is effective at increasing your feeling of fullness, stool size and bulk and helps reduce constipation and hemorrhoids

Soluble fiber:

• On the other hand, soluble fiber forms a gelatin-like substance in the intestines and increases the water content in stool. 

How many fibers should you eat?

Approximately 1 gram of fiber for every 100 calories is recommended.   This translates to roughly 25 grams per day.   As a rule of thumb you can always go back to the food guide pyramid, which recommends enough fruit, vegetable, and grain servings.   Please note, however, that this only works if a variety of foods are consumed.

Health Benefits That Come From Eating A High Fiber Diet

• reduces the risk of developing hemorrhoids
• reduces the  risk of forming diverticulitis
• reduces the risk colon cancer

Health Tips

           Eat a variety of grain products.   This includes everything from breads, cereals, pasta, and rice, to fruits and vegetables. Foods that are particularly rich in fiber include dry beans, lentils, and peas. You can also increase your fiber intake by making a conscious effort to eat more whole grains, whole-grain products, dry beans, and fiber-rich vegetables. While eating whole grains it’s good practice to increase fluid intake since insoluble fiber attracts water and tends to absorb it from the wall of your intestines.  

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