Colon cancer dietary fiber

International Agency for Research on Cancer, Dietary fiber, transit time, fecal bacteria, steroids and colon cancer in two Scandinavian populations. Lancet, 2 207 (1977). 

CUMMINGS J H (1992) Fecal weight, colon cancer and dietary fiber intake of non-starchy polysaccharide(dietary fiber). Gastroenterology, 103 1783-9. 

Graf, E. and Eaton, J.W. (1985). Dietary suppression of colonic cancer. Fiber or phytate. Cancer 56, 717-718. 

Dietary and pharmacologic agents influence the risk of colon cancer. Diets high in fat and low in fiber are associated with increased colon cancer risk, whereas the regular use of aspirin (and other NSAIDs) and calcium supplementation may decrease the risk of colon cancer. 

In summary, the true association between most dietary factors and the risk of colon cancer is unclear. The protective effects of fiber, calcium, and a diet low in fat are not completely known. Lifestyle factors such as NSAID use and hormone use appear to decrease the risk of colorectal cancer, whereas physical inactivity, alcohol use, and smoking appear to increase the risk of colon cancer. Clinical risk factors and genetic mutations are well-known risks for colon cancer. 

PO008 Nordgaard, I., H. Hove, M. R. Clausen, and P. B. Mortensen. Colonic production of butyrate in patients with previous colonic cancer during long-term treatment with dietary fiber (Plantago ovata seeds). Scand J Gastroenterol 1996 31(10) 1011-1020. 

A resurgence of interest in dietary fiber has been stimulated by epidemiological evidence of differences in colonic disease patterns between cultures with diets containing large quantities of fiber, and Western cultures having more highly refined diets. Many African countries, for example, are relatively free of diverticular disease, ulcerative colitis, hemorrhoids, polyps, and cancer of the colon Whereas most interest has focused on the beneficial role of dietary fiber, there is also concern that high fiber diets may cause disturbances in the absorption of nutrients such as minerals (see Mineral Nutrients) and vitamins. 

In the study on colorectal cancer (Table 20.4), a reduced risk was found for increasing intake of anthocyanidins (OR, 0.67 for the highest versus the lowest quintile,p-trend, 0.001), flavonols (OR, 0.64,p-trend < 0.001), flavones (OR, 0.78, p-trend, 0.004), and isoflavones (OR, 0.76, p-trend, 0.001). [Rossi et al., 2006], The estimates did not substantially differ for colon and rectal cancers. After allowance for fruit and vegetable consumption, for dietary fiber, or for micronutrients previously associated to this tumor including vitamin C, the associations with flavonoids did not change by more than 10%. A recent case-control study of 1456 pairs of cases and controls conducted in Sweden confirmed a significant decrease in risk of colorectal cancer for intake of anthocyanidins and flavonols [Theodoratou et al., 2007], but there was no relation for isoflavones and flavones. However, the results on isoflavones and flavones are questionable due to the unusually and generally low intakes of the populations studied. In the Italian population, anthocyanidins were derived mainly from wine, red fruit, and onions, and flavonols from apples or pears, wine, and mixed salads. 

As previously mentioned, flaxseed is a rich source of dietary fiber (28%). Dietary fiber has been widely viewed as a component essential to lowering the risk of colon cancer. The flaxseed protein is similar to soy thus may be beneficial to health. Bhathena et al. (2002) first reported that flaxseed protein was effective in lowering plasma cholesterol and triacylglycerides (TAG) compared to soy and casein protein in male F344 and obese SHR/N-cp rats. The role of protein in disease prevention warrants further investigation. Components, such as PAs and flavonoids, may also contribute to the health benefits of flaxseed. 

Carbohydrates which are digestible appear to have no dramatic effect on metabolism of xenobiotics however, the nondigestible carbohydrates can mediate the toxicity of a xenobiotic. Dietary fiber can reduce nutrient availability by absorbtion of certain minerals and/or vitamins. Inclusion in the diet of fiber has been associated with a lower incidence of colon cancer, and this... 

Dietary fiber has been suggested to play a protective role against chemically-induced toxicity (1) and against colon cancer (2). However, the mechanism(s) by which dietary fiber modulates chemical toxicity or colon cancer has not been well studied. The fiber fraction of the diet is resistant to mammalian digestive enzymes and consequently dietary fiber is not absorbed from the small intestine (3). However, certain types of dietary fiber specifically fermentable fibers, including the pectic substances and hemicelluloses, are readily digested by the intestinal microflora (4,5). Pectic... 

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. 

Epidemiologic studies indicate that diets high in total fat and saturated fat and low in certain fibers are associated with an increased risk for colon cancer. In addition, certain dietary fibers and cruciferous vegetables have been associated with a reduced risk in several populations consuming the diets high in total fat. 

Dietary Fat and Fiber and Bile Acid Excretion. In order to understand the specifics of the mechanisms whereby dietary fat influences colon cancer, the effect of type and amount of dietary fat on biliary and fecal bile acids was studied in rats (40,47,48). These... 

The incidence of colon cancer is high in western populations except for Japan and low in most developing nations. The high incidence is associated with high dietary fat. Low fiber intake has also been associated with the high colon cancer incidence in some populations. 

The epidemiologic data, relative to dietary fiber, has been supported by animal studies but experiments with dietary fat have been conflicting and generally do not indicate a fat effect. Other dietary factors which associate with colon cancer in animal studies are deficits of lipotropes and of vitamin A. 

Studies of the incidence of and mortality from colon cancer at the international level suggest an association of this neoplasm with total dietary fat (33,34). Lui et al (35), studying the disappearance rate of food and mortality from colon cancer between the years 1967-1973 in 20 industrialized countries, concluded that there was a direct correlation of this tumor type and the per capita intake of total fat, saturated and monounsaturated fat and cholesterol. Furthermore, fiber intake was inversely correlated with colon cancer in these studies. 

Table XIV. Dietary Fiber and Colon Cancer in Rats Induced by Two...

---