Study Shows Fish Oil Does Not Prevent Cancer and May Increase Risk in Women

Add another one to the list of studies that fail to support the use of commonly used supplements.

Omega-3 fatty acids or fish oil are often ascribed significant health benefits.

Mainly they are believed to reduce triglyceride levels and have protective effects against cardiovascular disease.

However, through anti-inflammatory and possibly antiproliferation pathways it is hoped that they may help to prevent cancer.

The latest trial analyzed the effect of B vitamin and fish oil supplementation on 2500 patients between the ages of 45-80 years of age who had suffered either a heart attack or stroke.

The patients were randomized into one of four groups: B vitamins, Omega-3 fatty eithers, neither or both. B vitamins included 0.56 mg of folate, 3 mg of B6, and .02 mg of B12. ωOmega-3 fatty acid supplements consisted of eicosapentaenoic and docosahexaenoic acid, 600 mg, in a ratio of 2:1.

Omega-3 Fatty Acids Increase Risk of Aggresive Prostate Cancer An increased risk of prostate cancer has been associated with high levels of heart-healthy omega-3 fatty acids in the blood. High levels of trans-fatty acids actually lowered the risk, the new study also found.

The research published in the American Journal of Epidemiology examined data from a country-wide study of 3,400 men. Those who had the highest blood percentages of omega-3 fatty acids - specifically docosahexaenoic acid (DHA), which is found in fatty fish - were two-and-a-half times more likely to develop a high grade tumor than those with the lowest levels.

It was also found that men with the highest level of trans-fatty acids - abundant in processed foods and associated with inflammation and heart disease - were 50 percent less likely to have the risk of aggressive prostate cancer.

"We were stunned to see these results, and we spent a lot of time making sure the analyses were correct," said lead researcher Theodore M. Brasky in a news release. "Our findings turn what we know - or rather what we think we know - about diet, inflammation and the development of prostate cancer on its head."

Despite the findings, Brasky and his colleagues still encourage men to eat their fair share of omega-3s.

The patients were treated and monitored for 5 years. By the end of the study period, cancer had occurred in 7% of the sample (145 men and 29 women).

Statistical analysis revealed there was no association between B supplementation and/or omega-3 supplementation and the risk of cancer in the group as a whole or men in particular. There was however an increased risk of cancer in women receiving the omega-3 supplements.

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The authors conclude "this study does not support dietary use of B vitamins or omega ω-3 fatty acids for cancer prevention. The preliminary evidence of adverse effects among women necessitates confirmation before firm conclusions could be drawn."