Studies Document Roles of Good and Bad Fats in Cancer

Two new studies add evidence supporting the role of omega-3 fish oils in reducing the risk of prostate and colon cancer.

In the first study, John S. Witte, PhD, of the University of California, San Francisco, and his colleagues compared the diets of 466 men diagnosed with aggressive prostate cancer and 478 age-matched control subjects. They also looked at how a genetic risk factor for prostate cancer was influenced by omega-3 intake.

Overall, men with a high intake of omega- 3 fats, which have anti-inflammatory benefits, had a 63 percent lower risk of developing aggressive prostate cancer, compared with men who consumed few omega-3 fats.

Men with a particular genetic variation in their Cox-2 gene, which promotes inflammation, combined with low intake of fish oils, had a five and one-half time greater risk of developing aggressive prostate cancer, compared with men who consumed a lot of fish oils.

In the second study, Karsten H. Weylandt, MD, PhD, of Massachusetts General Hospital, Boston, and his colleagues studied the effects of arachidonic acid (AA), a pro-inflammatory omega-6 fat, and docosahexaenoic acid (DHA), one of the principal anti-inflammatory omega-3 fats.

Using colon cancer cells, he found that AA promoted cell growth, whereas DHA reduced the viability of cancer cells. DHA reduced AA-stimulated cell proliferation and significantly lowered the production of prostaglandin E2, a pro-inflammatory byproduct of AA. In addition, DHA reduced colon cancer cell proliferation, with higher doses having a greater effect. DHA also reduced the activity of Cox-2.

References: Fradet V, Cheng I, Cassey G, et al. "Dietary omega-3 fatty acids, cyclooxygenase-2 genetic variation, and aggressive prostate cancer risk." Clinical Cancer Research, 2009;15:2559- 2566. Habbel P, Weylandt KH, Lichopoj K, et al. "Docosahexaenoic acid suppresses arachidonic acid-induced proliferation of LS-174T human colon carcinoma cells." World Journal of Gastroenterology 2009;15:1079-1084.