|MadSci Network: Anatomy|
You should do more website searches regarding "soluble" vs. "insoluble" fiber and why dietary natural fiber from fruits, vegetables and grains are healthful.This is not due to management of obesity. Sawdust, or wood pulp, is an insoluble fiber that is not hydrolysed since it is insoluble in gastric juice and humans have no intestinal enzymes to degrade it. It is essentially cellulose that has been used in the past at very low levels (1-6 grams), made into derivatives, and used as a bulk-forming laxative. Due to osmotic effects in the lower gut, it will take up water. However, it can deplete electrolytes(sodium and potassium) and can be quite dehydrating. With a relatively large amount of intake (a slice of sawdust bread) it can be quite irritating and painful within the human intestinal tract, may cause very painful gas formation due to some bacterial action in the lower bowel, and can produce partial or complete intestinal obstruction. Textbooks on human physiology/pharmacology can give additional information. There is some information in "Toxic Hazards in Food", D.M. Conning and A.B.G. Lansdown, 1983. Croom Helm Ltd, Beckenhem, Kent.
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