Fiber 101:
Soluble Fiber vs Insoluble Fiber
Written
by: Gloria Tsang, RD
Benefits of Fiber
We all know the benefits of fiber! Fiber not only promotes health, it also help reduce the risk for some chronic diseases. For instance, fiber prevents constipation, hemorrhoids and diverticulosis. Fiber is also linked to prevent some cancers especially colon and breast cancer. In addition, fiber may help lower the LDL cholesterol (the Bad cholesterol) and the total cholesterol therefore reducing the risk of heart disease. Furthermore, fiber can help lower blood sugar therefore help better manage diabetes.
Types of Fiber: Soluble Fiber and Insoluble Fiber
Both soluble and insoluble fiber are undigested. They are therefore not absorbed into the bloodstream. Instead of being used for energy, fiber is excreted from our bodies. Soluble fiber forms a gel when mixed with liquid, while insoluble fiber does not. Insoluble fiber passes through our intestines largely intact.
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Insoluble Fiber
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| Functions of Insoluble Fiber |
move bulk through the intestines
control and balance the pH (acidity) in the intestines
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| Benefits of Insoluble Fiber |
promote regular bowel movement and prevent constipation
remove toxic waste through colon in less time
keep an optimal pH in intestines to prevent microbes from producing cancer substances; therefore preventing colon cancer |
| Food Sources of Insoluble Fiber |
Whole-wheat products
Wheat oat
Corn bran
Flax seed
Vegetables such as green beans, cauliflowers and potato skins
Fruit skins and root vegetable skins
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Soluble Fiber
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| Functions of Soluble Fiber |
bind with fatty acids
prolong stomach emptying time so that sugar is released and absorbed more slowly
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| Benefits of Soluble Fiber |
lower total cholesterol and LDL cholesterol (the Bad cholesterol) therefore reducing the risk of heart disease
regulate blood sugar for people with diabetes
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| Food Sources of Soluble Fiber |
Oat/Oat bran
Dried beans and peas
Barley
Flax seed
Fruits such as oranges and apples
Vegetables such as carrots
Psyllium husk
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Key Message: An average diet contains 75%:25% insoluble fiber: soluble fiber. When making a food choice decision, don't worry about choosing a specific type of fiber. Indeed many foods such as oat, oat brans, psyllium husk and flax seed are rich in both insoluble and soluble fiber. Eating enough fiber is more important!!! If you eat at least 5 servings of fruits/vegetables as well as at least 5 servings of grain products per day, you are very likely meeting the fiber requirements.
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