Colon Cancer: Does Wheat Bran Reduce the Risk?

K-State, Wichita State collaborative research studies wheat bran from different wheat varieties, effect on suppressing colon cancer

MANHATTAN -- We've heard the conflicting information: Wheat bran can reduce the risk of colon cancer in humans; wheat bran does not reduce the risk in humans.

But which one is true?

Both, sort of.

In the mid-1990s, grain science nutritionists at Kansas State University discovered that bran from one variety of wheat actually suppressed cancer in laboratory tests, while bran from another wheat variety did not.

According to Ronald Madl, director of bioprocessing and industrial value added programs with K- State's department of grain science and industry, the confusion set in because the resulting medical literature really did not appreciate the genetic diversity in wheat -- that not all wheat bran is the same.

"As a consequence, medical literature that followed the initial work sometimes said that wheat bran did suppress cancer," Madl said. "Other medical literature said it did not suppress cancer."

In a cooperative effort that picked up where that previous research left off, Madl and other researchers from K-State -- including Carol Klopfenstein, professor emeritus of grain science and industry, Delores Takemoto, professor of biochemistry, and Weiqun Wang, assistant professor of human nutrition -- joined with John Carter, associate professor of physical therapy at Wichita State, and discovered the diversity of phytochemicals in wheat bran. They tested about 120 varieties, all with different levels of antioxidants, from very high to very low. Further studies showed wheat bran with a higher antioxidant content demonstrated a potential to suppress cancer cells.

Madl said in subsequent testing on human cancer cells, the bran from high antioxidant wheat varieties either actually killed some of the cancer cells or stopped their growth; the medium and low antioxidant varieties had less of or no effect -- the cancer cells kept growing like normal.

Further testing has shown that wheat high in antioxidants demonstrated a significant suppression in both size and number of tumors, while intermediate levels of wheat antioxidants experienced an intermediate level of cancer activity.

"Since then, we have been trying to move this research to the next stage, understanding which particular compounds are responsible for this benefit," Madl said. "Antioxidant activity is expressed by a lot of chemical compounds, but that doesn't mean that all antioxidants express that same beneficial, biological effect. Now, we're trying to determine which antioxidants are actually responsible for cancer suppression."

Madl said K-State wheat breeders would like to enhance the levels of antioxidants in wheat.

"The long-term opportunity is that we could produce new wheat varieties with higher levels of antioxidants, and then carry out research to show that these varieties can reduce cancer risk," he said.

Madl said that once researchers have determined the wheat bran varieties with enhanced levels of antioxidants, clinical studies could be considered for humans to demonstrate if wheat bran could reduce the risk of colon cancer.

Madl said K-State research is currently focused on testing methodology. Development of more rapid screening methods for antioxidants in wheat could make the screening process for wheat breeders, as well as making the wheat selection process for food processors, quicker and more feasible.

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Source: Source: Ronald Madl, , [email protected].
http://www.mediarelations.k-state.edu/WEB/News/MediaGuide/rmadlbio.html
News release prepared by: Keener A. Tippin II,

Used with permission.