In a study of middle-aged men, high intake of linoleic acid, an unsaturated fatty acid found in certain plants and vegetables, seemed to lower the risk of prostate and other cancers, Finnish researchers report.

The authors say these findings hint that recommendations to substitute dietary linoleic acid for saturated fat to prevent heart disease may have the added benefit of protecting against cancers.

“Dietary and serum fatty acid composition has been implicated in the (development) of prostate and other cancers, but findings have been conflicting,” Dr. David E. Laaksonen from the University of Kuopio and colleagues explain in the International Journal of Cancer.

The investigators studied the association between dietary fatty acid and cancer risk in 2002 middle-aged men who were cancer-free during the first 4 years of the study.

After nearly 13 years, 151 men had developed cancer, including 46 with prostate cancer.

Men who consumed the highest amounts of linoleic acid were 45 percent less likely to develop prostate cancer than their peers who consumed the lowest amounts. High intake of linoleic acid also reduced the risk of other cancers, but the magnitude was not as great as that seen with prostate cancer.

Men with high blood levels of linoleic acid, omega-6 fatty acids, and polyunsaturated fatty acids were less likely than men with low levels to develop prostate cancer. This held true even after considering other factors that might influence cancer risk, such as obesity and physical activity.

Laaksonen and colleagues conclude, “substitution of linoleic acid for saturated fat in middle-aged men consuming a high saturated-fat diet may decrease the risk of prostate and other cancers,” although they acknowledge that other nutrients associated with vegetable fats may be responsible for the protective effect.

SOURCE: International Journal of Cancer, September 1, 2004.