Suppression of colonic cancer by dietary phytic acid

Abstract

Large differences exist between human populations in the frequency of colonic cancer. Epidemiological evidence indicates that these differences are strongly influenced by country of residence, and a negative correlation has been found between the fiber content of the diet and frequency of colonic cancer. This has prompted the hypothesis that high-fiber diets are in some way protective. However, reanalysis of the dietary data provides equally strong support for the hypothesis that the protective element may be phytic acid (inositol hexaphosphate). This heat- and acid-stable substance is present in high concentration in many food items, including cereal grains, nuts, and seeds. Phytic acid forms chelates with various metals and suppresses damaging iron-catalyzed redox reactions. Inasmuch as colonic bacteria have been shown to produce oxygen radicals in appreciable amounts, dietary phytic acid might suppress oxidant damage to intestinal epithelium and neighboring cells. Indeed, rapidly accumulating data from animal models indicate that dietary supplementation with phytic acid may provide substantial protection against experimentally induced colonic cancer. Should further investigations yield additional support for this hypothesis, purposeful amplification of dietary phytic acid content would represent a simple method for reducing the risk of colonic carcinogenesis.

Germination: a means to improve the functionality of oat

“…On the other hand, phytic acid has also been reported to have health promoting effects. Phytic acid and its degradation products are believed to contribute to prevention of colon cancer and cardiovascular diseases (Graf andEaton 1993, Shamsuddin 1995). Oat phytate is known to be difficult to degrade Sandberg 1992, Marklinder et al 1995).…”

Antimutagenic and anticarcinogenic effects of wheat bran in vivo

“…The chemopreventive effect of whole-wheat flour has been attributed to its high levels of fiber and phytic acid [myo-inositol hexakis (dihydrogen-phosphate)] (Graf and Eaton, 1993). Whole-wheat flour and phytic acid protect against new biomarkers of colon cancer, reducing nuclear antigens and cell proliferation, for example (Jenab and Thompson, 1998).…”

Characterization of inositol hexakisphosphate (InsP6)3‐mediated priming in human neutrophils: lack of extracellular [3H]‐InsP6 receptors

“…Initial interest focused on its ability to suppress the development of colonic cancer in animal models, probably by chelating metal ions and thereby limiting mitogenic iron-catalysed redox reactions (Graf & Eaton, 1993). It has also been shown to lower blood pressure and heart rate in a reversible manner when infused into specific regions of the rat brainstem (Vallejo et al, 1987).…”