If a Blog can be a call for help, then this is it! Since the recent high-profile paper in JNCI (https://jnci.oxfordjournals.org/content/early/2013/07/09/jnci.djt174.abstract) suggesting that Omega 3 supplements increase the risk of Prostate Cancer and induce high grade prostate cancer, I am plagued by patient and colleague concerns about whether or not men should stop taking Omega 3 supplements! I know that health care providers all over the world have been similarly inundated. What are we to say to our patients?
Let us first look at the paper. The authors used data collected as part of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) to determine whether men with high levels of plasma phospholipid fatty acids (high levels of which are present in fish oil supplements), namely long-chain ω-3 polyunsaturated fatty acids ([LCω-3PUFA], were at higher risk of developing prostate cancer. The case subjects in the study were 834 men diagnosed with prostate cancer, of whom 156 had high-grade cancer. The comparison cohort consisted of 1393 men selected randomly at baseline and matched to case subjects on age and race. Proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for associations between fatty acids and prostate cancer risk overall and by grade. The results? Compared with men in the lowest quartiles of LCω-3PUFA, men in the highest quartile had increased risks for low-grade (HR = 1.44, 95% CI = 1.08 to 1.93), high-grade (HR = 1.71, 95% CI = 1.00 to 2.94), and total prostate cancer (HR = 1.43, 95% CI = 1.09 to 1.88). These results are strong enough for the authors to conclude that there is increased prostate cancer risk among men with high blood concentrations of these plasma phospholipid fatty acids, and that “the consistency of these findings suggests that these fatty acids are involved in prostate tumorigenesis”.
Crikey! Fish oil supplements increase risk of prostate cancer! Is it really so?? Is the study methodology robust enough to change practice? Undoubtedly, there are a lot of patients taking these supplements, some prescribed by medical practitioners; even my lovely ophthalmologist wife tells me that nearly every patient with macular degeneration worldwide is on it! My knowledge of antioxidants is somewhat pedestrian and I feel like an amateur in advising whether or not men should discontinue Omega 3 supplements.
What should we tell those who ask us? All comments gratefully received.
Dr David Quinlan
Consultant Urologist, St Vincent’s Hospital,
Senior Lecturer, University College Dublin