Eat well, but don't feed a cancer cell.
|Author:||Bliss, Rosalie Marion|
|Publication:||Name: Agricultural Research Publisher: U.S. Government Printing Office Audience: Academic; General Format: Magazine/Journal Subject: Agricultural industry; Biotechnology industry; Business Copyright: COPYRIGHT 2010 U.S. Government Printing Office ISSN: 0002-161X|
|Issue:||Date: July, 2010 Source Volume: 58 Source Issue: 6|
|Topic:||Event Code: 310 Science & research|
|Product:||Product Code: 8000220 Cancer & Cell R&D NAICS Code: 54171 Research and Development in the Physical, Engineering, and Life Sciences SIC Code: 8731 Commercial physical research; 8733 Noncommercial research organizations|
|Organization:||Government Agency: United States. Agricultural Research Service|
|Geographic:||Geographic Scope: United States Geographic Code: 1USA United States|
Scientists do not know exactly why one person develops cancer and another does not. But Agricultural Research Service chemist Thomas Wang, who specializes in cancer prevention research, says that there are "layers" of factors involved in the development of the disease. Wang works at the ARS Diet, Genomics, and Immunology Laboratory, which is part of the Beltsville (Maryland) Human Nutrition Research Center.
Research shows that certain external risk factors increase the chance that a person will develop cancer. These include the molecules that are introduced into the human body by way of ingestion. "This layer involves peoples' diet complexity," says Wang. "Diet is a complex mixture of bioactive compounds that trigger huge amounts of biological activity."
Another major layer is genetics. "People have their own individual genotypes that are dictated by their ethnicity, gender, and inherited traits," says Wang. Some of those traits involve susceptibilities to cancer.
While individual nutrients are sometimes touted in the media as being able to reduce the risk of developing certain cancers, in fact, such findings can only be confirmed through large clinical trials. Still, evidence from cell culture, animal models, and population studies suggests that interactions among combinations of certain plant chemicals are involved in slowing or possibly lowering the risk of cancer development.
Phytochemicals in Foods
While research suggests that diet can have a protective effect against some chronic diseases, other research is being conducted to learn what dietary components are linked to causing chronic diseases.
Vegetables, fruits, whole grains, beans, nuts, and seeds contain thousands of bio-active phytochemicals. Other compounds are found in some meats, poultry, and fish. Some of these compounds turn on genes that are protective against cancer and turn off other genes linked to cancer promotion.
"Gauging the benefits of consuming these dietary compounds involves careful tracking of concentration, timing, and interactions with other compounds," says Wang.
Wang published a complementary cell-culture and animal-model study showing that concentrations of resveratrol--a highly bioactive compound found in grapes and other plant foods--actually turned out to be a double-edged sword when it came to mitigating cancer risk.
First, Wang exposed human prostate cancer cells to resveratrol and found that it inhibited the cells' growth. He further tested the cells gene expression. Exposures to male sex hormone are known to increase prostate cancer risk. Wang found that resveratrol actually inhibited male-sex-hormone-mediated pathways.
Wang then tested the effects of resveratrol on a group of laboratory animals that had sex-hormone-dependent tumor cells. Half of those animals were fed a daily diet that included 3 to 6 milligrams of purified resveratrol (equal to roughly the amount in five glasses of wine or grape juice). At first, the tumor cells in the resveratrol-fed lab animals did not grow. But as the resveratrol consumption continued, blood vessels developed around the tumors, effectively setting up a system of feeding the tumors.
"This showed that the concentration of the plant compound is important, but 