Dietary fiber is that part of plant cell walls (such as ligans and polysaccharides) which our bodies cannot digest. There are two main types of fiber: insoluble and soluble. The best known insoluble fiber is cellulose. An example of this type of fiber is wheat bran. Wheat bran has been used for years to relieve constipation as it can bind a lot of water. However, insoluble fiber such as wheat brandoes not have as many benefits as do soluble fibers.

 

Soluble fibers include: hemicelluloses (oat bran), gums (guar gum), mucilages (psyllium seeds), pectins (apples) or lignans (dandelion root). These water soluble gel-forming fibers provide many beneficial effects including:

 

 

• Decreased transit time (food passes through the intestines more quickly)
• Decreased appetite
• Decreased blood fats
• Delayed stomach emptying (the stomach releases food into the intestines more slowly)
• Increased gastric and pancreatic secretions to aid digestion
• Increased stool weight
• Increased production of short-chain fatty acids (fuel for intestinal cells)
• More advantageous intestinal bacteria
• More soluble bile (to prevent formation of gall stones)

 

Fiber can relieve both constipation and diarrhea by affecting the transit time. Cultures that eat a high fiber diet usually have a transit time of 20 hours and a fecal weight of 500 grams. In contrast, those cultures who typically eat a low fiber diet have a transit time of greater than 48 hours and a fecal weight of only 100 grams. There is a direct correlation between transit time and stool weight and size. A larger, bulkier stool not only passes through the colon more easily, but also requires less pressure and straining during defecation.

 

Although dietary fiber increases the rate of transit through the gastrointestinal tract, it slows the rate at which the stomach empties, thus reducing after-meal elevated blood sugar. Also, enzymes secreted by the stomach, and pancreas increase in response to fiber, enhancing digestion.

 

A high fiber diet may also promote lactobacillus bacteria (good ones) while inhibiting endotoxin-producing bacteria (bad ones) in the colon. Having the proper microflora in the intestines helps with elimination and protects against foreign attack by other pathogenic bacteria.

 

The water-soluble gels and mucilaginous fibers can help lower serum cholesterol and triglyceride levels. When bile acid and fatty compounds bind to these fibers, more cholesterol and bile salts are excreted through the feces. Dietary fiber can reduce the synthesis of cholesterol and increase the conversion of cholesterol to bile acids.

 

Fiber may also play a major role in weight loss programs. Fiber is of benefit because it:

 

1) increases the amount of chewing, 2) increases the amount of calories excreted by the body, 3) alters secretion of digestive enzymes and improves glucose tolerance by delaying the rate at which the stomach empties. This same effect also allows the individual to feel fuller longer.

 

Fiber can also be obtained through a diet rich in beans, whole grains, fruits, and vegetables. It is best to get at least 20-35 grams of fiber daily through diet. Eat all foods in the least processed form for optimal health, e.g. fresh produce, and whole unprocessed grains (processing removes fiber). I would advise against sticking to only one source of fiber &endash; as an example, some individuals take a portion of wheat bran per day and expect it to be enough. Instead, make sure to have a number of fiber sources in your diet, soluble AND insoluble.

 

If you have been eating a low fiber diet, you may initially experience some gas if you drastically increase fiber intake, so ease into it gradually and drink plenty of water (aim for 2 quarts daily) to keep things moving through your digestive system.