Small intestine, fiber effects

Mecfianism of Action A cinchona alkaloid that relaxes skeletal muscle by increasing the refractory period, decreasing excitability of motor end plates (curare-like), and affecting distribution of calcium with muscle fiber. Antimalaria Depresses oxygen uptake, carbohydrate metabolism, elevates pH in intracellular organelles of parasites. Therapeutic Effect Relaxes skeletal muscle produces parasite death. Pharmacokinetics Rapidly absorbed mainly from upper small intestine. Protein binding 70%-95%. Metabolized in liver. Excreted in feces, saliva, and urine. Half-life 8-14 hr (adults), 6-12 hr (children). 

A major complication of constipation in the elderly is fecal impaction, a potentially serious condition that can result from ignoring impulses to defecate. Impaction is the buildup of fecal mass that becomes too large to expel. Increasing dietary fiber is part of the management program for chronic constipation of the elderly. Addition of bran (6-20 g/day) increases fecal weight and increases the frequency of defecation. When wheat bran is not effective, the laxative lactulose is recommended. Lactulose is a disaccharide composed of galactose and fructose connected by a p(l 4) bond. This compound is absorbed poorly in the small intestine because of the absence of enzymes that catalyze its hydrolysis. 

The effect of dietary wheat bran and dehydrated citrus fiber at 15% level and 5% dietary fat on intestinal carcinogenesis induced by AOM and DMAS was studied in male F344 rats (44,45). Composition of diets was adjusted so that all animals in different experimental groups consumed approximately the same amount of protein, fat, minerals and vitamins. The animals fed the wheat bran or citrus fiber and treated with AOM had a lower Incidence (number of animals with tumors) and multiplicity (number of tumors/tumor bearing rat) of colon tumors and tumors of the small Intestine than did those fed the control diet and treated with AOM (Table II 15). Although 15% purified pectin in the diet (41) inhibited the colon tumor incidence better than did 15% dehydrated citrus fiber, in this study the Inhibition of colon tumor multiplicity was more pronounced with the dehydrated citrus fiber compared with purified pectin. Because dehydrated citrus fiber contains about 20% pectin, the pectin content of this diet was considerably lower than that of the diet used in... 

Dietary fiber is only one of several possible pharmacologically active substances found in foods, and present in high concentrations in leguminous seeds which may be responsible for the different rates of digestion and blood glucose responses of different meals. Enzyme inhibitors, lectins and saponins are other so called antinutritional factors, also associated with dietary fiber which are able to alter small intestinal function (48). The gastrointestinal tract evolved to deal with these constituents in foods so that while toxic in large amounts (as in uncooked beans) small amounts may have beneficial effects. 

The application of the phytogenic feed additive tested shows some potential for optimizing rumen function. Positive effects were especially observed for the microbial activity and the concentration of volatile fatty acids in the rumen. Furthermore, bacterial protein reaching the small intestine was slightly increased and crude fiber digestibility was numerically improved. 

In recent years, there has been increasing interest in those carbohydrates that escape absorption in the small intestine and enter the colon, where they may have specific health benefits due to their fermentation by the colonic microflora and their effect on gut physiology. This entry considers the definition, classification, dietary sources, methods of analysis, colonic fermentation, and health benefits of both resistant starch and oligosaccharides, and compares them with those of dietary fiber. 

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