Dietary fibers are the indigestible portions of plants. Fiber is abundant in many plant-based foods, especially in whole-grain foods, the skins of fruits and leafy vegetables. Although your body does not have the enzymes that digest fiber, fiber provides many benefits that keep you healthy and prevent diseases.
Types
Soluble fiber absorbs water, forming a viscous solution in your intestinal tract. It slows the rate of nutrient absorption in your body. In the stomach, soluble fiber causes distention and slows gastric emptying. In the small intestines, it slows the absorption of sugars, fats and bile.
Insoluble fiber does not change in structure as it passes through your intestinal tract. It increases the amount of bulk in your large intestines and also slows down the absorption rate in your intestines.
Lowers Cholesterol
Dietary fiber helps reduce cholesterol in your body by removing any residue cholesterol in your intestines. According to biologist George Mateljan, author of "World's Healthiest Foods," fiber reduces the amount of bile reabsorbed back in the intestines. This triggers your liver to synthesize more bile by taking in cholesterol from your blood. This decreases the amount of low-density lipoproteins, or LDLs, which are a major contributor to high cholesterol and cardiovascular diseases by delivering cholesterol into your blood vessels.
Other Benefits
Dietary fiber helps diabetics by slowing the absorption rate in your bloodstream, which prevents a sharp rise in blood glucose level. It also helps reduce constipation, colon cancer and hemorrhoids. Fiber increases satiety by slowing down digestion and creating bulk in your stomach. Since it does not provide your body with energy, foods with high fiber content usually have low calories, which is ideal for those who wish to lose weight.
Warning
If you have a small stomach capacity, too much fiber may satisfy hunger, but you may not get all the nutrients your body needs. This is common among children and adults of small stature. According to Mateljan, too much fiber can also cause excessive abdominal discomfort and gas due to the bacteria in your large intestines that break down the fiber. If you drink too little water in a high-fiber diet, you can get constipated and experience intestinal blockage.
Recommended Intake
Dietitian Ellen Coleman, author of "Ultimate Sports Nutrition," recommends that you eat a minimum of 25 g of fiber daily. This amount should include both soluble and insoluble fibers. In every meal and snack, add some fruit, vegetables or whole grains, such as apples, lettuce, bok choy, beans, brown rice, whole-wheat bread and nuts.
References
- "World's Healthiest Foods"; George Mateljan; 2006
- "Ultimate Sports Nutrition"; Ellen Coleman; 2004
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