Soluble fiber forms a soft gel when exposed to moisture. While soluble fiber adds to fecal mass, the principal action of soluble fiber is in the bacterial fermentation of this gel into fatty acids. These fatty acids create a natural lubricating, laxative effect in the colon. Soluble fiber not only works as a stool softener and colon cleanser, but it has been found to bind bile salts, reducing blood cholesterol levels and insulin secretion by slowing glucose absorption.

Insoluble fiber is, simply, bulk that experiences little change as it passes through the body, stimulating evacuation through an increase in fecal mass. Increased mass stimulates peristalsis, speeding transit time in the colon.

*The technical services division of Enzymes, Inc., received this question from one of its customers. To fit this blog, the question was modified from its original version. The response from clinical nutritionist Dan Kaur Weamer also has been modified. The answer is not intended or implied to be a substitute for professional medical advice provided by a physician or other health care professional. Readers are asked to consult other sources as well as to obtain direct consultation with a physician when making decisions about their health care.