Which of the following is not degraded by colonic flora?

Fermentation In Colon Both mictobiota and host obtain clear benefits from this association Bacteria supply the host with butyrate (main fuel for colonic epithelial cells) Bacterial fermentation products are absorbed and used as a source of energy Main sources of energy for intestinal bacteria are complexe carbohydrates: Starches & nonstarch polysaccharides (NSPs), also known as dietary fibre Lignin is not fermented by human colonic flora and attracts water thus producing bulk Cellulose are only paially fermented Fruit pectin are completely fermented Highly fermentable NSPs provide minimal bulk and slow transit time Constipation, diveiculosis and colon cancer are uncommon in populations with a high intake of roughage (I.e., water insoluble NSPs) Water-insoluble fibers (Lignin) Used for the treatment of constipation Water-insoluble NSPs (Pectin) Used to treat diarrhea Ref: Sabiston 20th edition Pgno : 1321