TUESDAY, Aug. 1 (HealthDay News) -- Altering the ratio of omega-3 and omega-6 fatty acids in the typical Western diet may reduce prostate cancer tumor growth rates, a new U.S. study suggests.

This study with mice is one of the first to show the impact of diet (in this case, more omega-3 fatty acids and fewer omega-6 fatty acids) on lowering an inflammatory response known to promote prostate cancer tumor progression. The finding could help lead to the development of new treatments, the researchers said.

The researchers, from the University of California, Los Angeles, used mice with a hormone-sensitive prostate cancer that closely resembles human prostate cancer. One group of mice was fed a diet that included 20 percent fat with a one-to-one ratio of omega-6 to omega-3 fatty acids. The other group of mice also received a diet with 20 percent fat, but mostly omega-6 fatty acids.

In the mice that received the balanced diet of fatty acids, tumor cell growth rates decreased by 22 percent and prostate specific antigen (PSA) levels decreased by 77 percent, compared to the mice that received the diet with mostly omega-6 fatty acids.

Omega-6 fatty acids, the predominant polyunsaturated fatty acids in the Western diet, are found in corn, safflower oils and red meats. Omega-3 fatty acids are found in cold-water fish, including salmon, tuna and sardines.

"Corn oil is the backbone of the American diet. We consume up to 20 times more omega-6 fatty acids in our diet compared to omega-3 acids," principal investigator Dr. William Aronson, professor in the department of urology at the David Geffen School of Medicine at UCLA and a researcher at UCLA's Jonsson Cancer Center, said in a prepared statement.

"This study strongly suggests that eating a healthier ratio of these two types of fatty acids may make a difference in reducing prostate cancer growth, but studies need to be conducted in humans before any clinical recommendations can be made," Aronson said.

The findings were published Aug. 1 in the journal Clinical Cancer Research.

More information

The American Heart Association has more about dietary fats.

-- Robert Preidt

SOURCE: University of California, Los Angeles, news release, Aug. 1, 2006

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