Dietary fibers carcinogenesis

REDDY B s, HAMID R, RAO c V (1997) Effect of dietary fiber ohgofmctose and inilin on colonic preneoplastic aberrant crypt foci inhibition. Carcinogenesis. 18 1371-4. 

Carcinogenesis inhibition. Polysaccharide fraction of the dried seed hulls, administered to rats by gastric intubation, was active vs tumor induction with N-ethyl N-nitro-N nitrosoguanidine h Rice bran, administered orally to male rats at a concentration of 4% of the diet, was active. A 1 1 combination of wheat bran and psyllium, at a total level of 8% dietary fiber, offers the highest protection against colon tumor development . 

The effects of dietary fiber on chemically-induced colon cancer in rats are variable being dependent on the carcinogen used and its mode of administration as well as the sex and strain of the rat. In most cases, however, dietary fiber has been found to inhibit carcinogenesis. 

Current research in animal models which suggests that the carcinogenic response to a variety of colon carcinogens is enhanced by the dietary fat and inhibited by several dietary fibers, indicates that these nutritional factors may operate during the promotional phase of carcinogenesis. The carcinogenic process in humans may... 

Jacobs, L.R. 1990. Influence of soluble fibers on experimental colon carcinogenesis, in Dietary Fiber Chemistry, Physiology, and Health Effects, eds., D. Kritchevsky, C. Bonfield and J.W. Anderson, New York Plenum, pp. 389-401. 

Klurfeld, D.M. 1992. Dietary fiber-mediated mechanisms in carcinogenesis, Cancer Res., 52(7) 2055s-2059s. 

O Neill IK, Goldberg MT, El Ghissassi F, et al. 1991. Dietary fiber, fat and beef modulation of colonic nuclear aberrations and microcapsule-trapped gastrointestinal metabolites of benzo[a]pyrene-treated C57/B6 mice consuming human diets. Carcinogenesis 12(2) 175-180. 

Effect of Conventional and Unconventional Dietary Fibers in Colon Carcinogenesis... 

These studies indicate that diets with a high Intake of total fat and a low Intake of certain fibers and certain vegetables are generally associated with an increased incidence of colon cancer in humans. Even in populations consuming high amount of fat, high dietary fiber acts as a protective factor in colon carcinogenesis. 

Possible Mechanism of Protective Effect of Dietary Fiber In Colon Carcinogenesis... 

The aforementioned limited results suggest that the protection against colon carcinogenesis afforded by dietary fibers, both conventional and unconventional, depends on the source of fiber and the type of carcinogen. 

The results of various studies on dietary fibers and experimental carcinogenesis have been extensively reviewed[40,49] and have not been entirely consistent. In general, however, dietary these morphological phenomena, hyperplasia and Increased colonic neoplasia, however, remains to be demonstrated. 

B. S. Reddy, Dietary fiber and colon carcinogenesis A critical... 

Increased fiber intake and the consumption of fruits and vegetables are well-known chemopreventive dietary strategies against colon carcinogenesis. It is reported that fiber intake reduces colonic transit time and increases the production of short chain fatty acids such as butyric acid. The latter is produced in the mammalian colon in mM concentrations as a by-product of anaerobic bacterial fermentation of dietary fiber. Butyric acid has been recognized as one candidates chemopreventive active against colon carcinogenesis because it induces apoptosis and differentiation in colon cancer cell lines. 

Reddy BS, Mori H and Nicolais M. 1981. Effect of dietary wheat bran and dehydrated citrus fiber on azoxymethane-induced intestinal carcinogenesis in Fischer 344 rats. J Natl Cancer Inst 66 553-557. 

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... 

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