Nutritional value of sugars and related compounds undigested in the small gut.

The nutritional consequences of the ingestion of NAS depend on the quantity ingested. At lower levels there is little effect on the absorption of other nutrients and the colonic microbiological-salvage mechanism operates and a substantial proportion of the energy is made available to the body through fermentation. The exact amounts that can be tolerated in this way vary for individuals and are different for different compounds. At higher levels of intake the capacity of the colonic digester is exceeded and the decreased transit time affects N, energy, electrolyte and water metabolism. The responses to NAS are an example of how the animal body is dependent on the bacterial content of the colon to enable that organ to perform its function of water and electrolyte conservation.