Contrary to the headlines, a new research study published in the July 2013 issue of the Journal of the National Cancer Institute suggests (but does not confirm) a link between omega-3 fatty acid levels and increased risk of prostate cancer. The study reports a 71% increased risk for high grade prostate cancer in men with elevated blood fish oil levels – that’s right, the participants were not actually queried on the amount of fish or fish oil supplements they consume . Instead researcher performed a single blood test measuring plasma omega-3 levels, a test that has not been proven to be a valid or reliable marker for omega-3-fatty acid status.
One of the biggest shortcoming of this kind of correlational study is that they did not make adjustments for confounding variables. What this means is that the authors did not take into account other well known risk factors for prostate cancer such as age, family history, weight and ethnicity. In fact, of all the study participants with prostate cancer, 80% were overweight/obese, 64% consumed alcohol regularly, 53% were smokers, and 30% had a first degree relative with cancer. Without adjusting for these confounding variables, the association between fish oil and prostate cancer is very weak.
While this study does not confirm cause-and-effect or even a strong correlation between fish oil and prostate cancer, it is always a good idea to speak with your doctor about the supplements you are taking. And keep in mind that naturopathic doctors are experts in nutrition, botanicals, natural medicines and targeted nutritional supplements.