Dietary fiber: classification and physiological role

Dietary fiber is an essential nutrient with known links to reduction in cardiovascular risk. Additionally, dietary fiber aids in laxation, improves glycemic control, and assists in weight maintenance. Dietary fiber is found in plant foods including whole grains, legumes, vegetables, fruits, and nuts. Dietary fiber is a nutrient of concern, with usual intakes in developed countries about half of recommended amounts. Fiber is also added to foods and beverages and consumed in dietary supplements. Not all fiber is alike with some fibers being extensively fermented in the gut while other fibers are not fermented at all. The byproducts of the fermentation of fiber in the gut confer health benefits that extend beyond the gut to the immune system and organs such as the liver, kidneys, and the brain.