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Soluble vs. Insoluble fiber.

Water-soluble fiber is viscous and composed mainly of plant pectin, gum, and mucilage. The first two are parts of the cell structure of plant walls and naturally coat seeds; they have gelling properties when mixed with water. Mucilage is a gelatinous glycoprotein produced by plants. Insoluble fiber is composed of cellulose and its less crystalline counterpart hemicellulose. Because it does not dissolve in water, this latter type of fiber bulks up as it absorbs water. Soluble fiber, on the other hand, becomes gelatinous and viscous. It too bulks up, but its primary role in bodily health is to bind to the bile acids in the small intestine. Soluble fiber takes these acids with it as it passes through the body, which in turn lowers LDL cholesterol and blood glucose levels by slowing glucose absorption in the small intestine. Researchers are still discovering the precise mechanism at work here, but when people with hyperlipidemia were given a medication that binds to and removes bile acids, their bad cholesterol improved and their blood glucose level lowered; soluble fiber has the same binding ability.

Insoluble fiber mainly eases the passage of foods through the digestive system and cleanses intestinal walls, whereas soluble fiber promotes actual changes in intestinal pH. Also, because soluble fiber ferments, it stimulates the growth of "friendly" bacteria in the gut. It is therefore known as pre-biotic. Insoluble fiber is by contrast inert. Both types increase food volume without increasing caloric content, providing satiety, and so they are widely associated with weight management.
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Publication:Running & FitNews
Article Type:Brief article
Geographic Code:1USA
Date:Jul 1, 2011
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