Chlorophyll helps prevent cancer, but ...

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CORVALLIS, Ore., Jan. 14 (UPI) -- Chlorophyll in green vegetables may protect against cancer when tested against modest carcinogen exposure, U.S. researchers say.

However, Tammie McQuistan, a research assistant working with George Bailey, a professor emeritus in the Linus Pauling Institute at Oregon State University, said chlorophyll increases the number of tumors at very high carcinogen exposure levels.

The study involved 12,360 rainbow trout as laboratory models, instead of more common laboratory mice because rodent studies are much more expensive, forcing the use of fewer specimens and higher carcinogen exposures.

"There's considerable evidence in epidemiologic and other clinical studies with humans that chlorophyll and its derivative, chlorophyllin, can protect against cancer," McQuistan said in a statement. "This study, like others before it, found that chlorophyll can reduce tumors, up to a point, but at very high doses of the same carcinogen, chlorophyll actually made the problem worse. This questions the value of an approach often used in studying cancer-causing compounds."

Beyond confirming the value of chlorophyll, the research raises serious questions about whether traditional laboratory studies done with mice and high levels of toxic exposure provide accurate answers to what is a real health risk, what isn't, and what dietary or pharmaceutical approaches are useful, McQuistan said.

The findings were published in the journal Food and Chemical Toxicology.