|Life Extension Update Exclusive |
Soy extract may help prevent colon cancer
The May 2004 issue of the Journal of Nutrition (http://www.nutrition.org/) published the results of a study showing that a substance found in soy helped prevent colon cancer in mice. The compound is soy glucosylceramide, known as soy GlcCer, a type of sphingolipid. Al Merrill, of Georgia Tech University, along with colleagues from Emory University and the Karmanos Cancer Institute, had previously conducted research which found that milk sphingolipids suppress tumor formation in the colon of experimental animals, and their latest research is the first to establish that a plant sphingolipid can do the same.
In the current study, mice who were administered the colon carcinogen DHM were provided with diets containing 0.025 percent or 0.1 percent soy GlcCer: amounts comparable to that found in soybeans. The investigators found that the compound reduced colonic cell proliferation in the upper half of the crypts by 50 percent when compared to animals who did not receive the compound. (Crypts are the indentations in the walls of the colon in which cells grow and replicate.) Aberrant crypt foci, which are an early marker of colon cancer, were reduced by 38 percent in the mice who received diets containing 0.025 percent soy GlcCer and 52 percent in those who received the 0.1 percent diet.
When mice bred to develop gastrointestinal cancer were administered the soy GlcCer enhanced diets, tumor formation was reduced by 22 percent in those who received the lower concentration and 37 percent in those who received the higher concentration of the compound.
Unlike many nutrients that are broken down in the digestive tract, soy GlcCer survives digestion which enables it to exert its cancer-fighting mechanism in the colon. Its mechanism of action appears to be that of lowering beta-catenin, a protein involved in cell growth.
Dr Miller commented, “Soy is known to have a number of health benefits, including the suppression of cancer. Based on our results, some of this benefit may be due to a group of molecules known as sphingolipids. We are looking for even more potent forms of these molecules that might be effective for cancer treatment. If naturally occurring sphingolipids like soy GlcCer suppress cancer in humans, this has the potential to allow the public to select their diets in a more rational way.”