Soy's cancer-fighting power explained

Soy's cancer-fighting power explained

University of Illinois researchers discovered the how a soy isoflavone protects against colon cancer.

Researchers have made progress in figuring out just how soy helps protect against cancer and it has everything to do with cell expression – and not the smiley emoticons you text with on your phone.

University of Illinois scientists found evidence that lifelong exposure to a component in soy called genistein protects against colon cancer by repressing a signal that accelerates cell growth, polyps and eventually malignant tumors. The study will be published in Carcinogenesis.

Our bodies completely replace the cells in the lining of our guts every week. In most colon cancer patients, however, the signal to grow is always on in the gut, leading to uncontrolled growth and malignancies. “Our study suggests that the aberrant Wnt signaling during the development of colon cancer can be regulated by soy-rich diets,” said Hong Chen, a U of I professor of food science and human nutrition in a release.

“The good news is that a diet rich in soy genistein represses those signals ...” said Yukun Zhang, a doctoral student in Chen’s laboratory.

Chronic exposure to genistein, a soy isoflavone, reduced the number of pre-cancerous lesions in the colons of laboratory rats exposed to a carcinogen by 40 percent and reduced the “grow” signaling to normal levels, she said. She said this shows that colon cancer is an epigenetic disease, meaning that dietary and environmental factors can influence genes to be switched on or off so you have a different pattern of gene expression, leading to a change in disease susceptibility.

It's long been known that immigrants from Asia, where soy is traditionally a food staple, experience rising levels of colon cancer as they adopt the eating habits of Western nations, she said. “The genetic information you inherit from your parents is not the whole story. Our dietary choices, our exposure to environmental toxins, even our stress levels, affect the expression of those genes,” she said.

This is good news for soy makers, sellers and eaters. The popularity of the stuff's bounced up and down over the years like a cube of fermented bean curd dropped on a marble floor.

For the complete business angle on all things protein, check out the Nutrition Business Journal / Engredea monograph report on protein here.

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