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Dietary Fiber
Non-digestible carbohydrate polymers and lignin intrinsic to plants, plus added isolated or synthetic non-digestible carbohydrates with demonstrated physiological benefit (FDA 2016 definition).
Also: Fiber, Roughage
Fiber is functionally classified as soluble vs insoluble, fermentable vs non-fermentable, viscous vs non-viscous. Effects include lower postprandial glycemia and cholesterol (viscous soluble: β-glucan, psyllium, pectin), increased fecal bulk and transit (insoluble: wheat bran, cellulose), and SCFA production (fermentable: inulin, resistant starch). DRI AI is 14 g per 1,000 kcal; actual US intake is roughly half that.
How each textbook covers it
Advanced Nutrition and Human Metabolism, 8th ed. (Gropper) — Glossary
Plant-derived carbohydrates and lignin not broken down by human digestive enzymes, reaching the colon largely intact. Includes cellulose, hemicelluloses, pectins, and β-glucans. Contributes to laxation, satiety, glycemic control, and microbiota fermentation.
duyff-complete-food-and-nutrition-guide-5e
Modern Nutrition in Health and Disease, 12th ed. — Ch 3: Carbohydrates
Fiber is functionally classified as soluble vs insoluble, fermentable vs non-fermentable, viscous vs non-viscous. Effects include lower postprandial glycemia and cholesterol (viscous soluble: β-glucan, psyllium, pectin), increased fecal bulk and transit (insoluble: wheat bran, cellulose), and SCFA production (fermentable: inulin, resistant starch). DRI AI is 14 g per 1,000 kcal; actual US intake is roughly half that.
Related terms
Cholesterol, Functional fiber, Prebiotic, Prebiotics, Resistant starch, SCFA, Total fiber