Men who eat a lot of oily fish or consume omega supplements should watch out, new research reveals that males with high blood concentrations of omega-3 fatty acids are at a higher risk of developing prostate cancer.
The finding comes from a large prospective study published in the Journal of the National Cancer Institute.
A 71 percent increased risk of high-grade prostate cancer and a 43 percent increase for all prostate cancers were associated with high concentrations of EPA, DHA, and DPA.
These results are consistent with a 2011 study carried out by the same research team which found that high concentrations of DHA more than doubled the risk of high-grade prostate cancer.
The researchers were shocked to find that higher blood levels of omega-3 fatty acids, usually promoted as good for the heart, were associated with a higher risk of aggressive prostate cancer.
The consistency of these findings could mean that "these fatty acids are involved in prostate tumorigenesis and recommendations to increase long-chain omega-3 fatty acid intake, in particular through supplementation, should consider its potential risks."
The paper's senior author and member of the Fred Hutch Public Health Sciences Division, Alan Kristal, Dr.P.H, said: "we've shown once again that use of nutritional supplements may be harmful."
Theodore Brasky, Ph.D., a research assistant professor at The Ohio State University Comprehensive Cancer Cente, added:
"What's important is that we have been able to replicate our findings from 2011 and we have confirmed that marine omega-3 fatty acids play a role in prostate cancer occurrence. It's important to note, however, that these results do not address the question of whether omega-3's play a detrimental role in prostate cancer prognosis."
The study compared the blood level concentrations of omega-3 fatty acids in 834 men who had been diagnosed with prostate cancer with samples from 1,393 men from the Selenium and Vitamin E Cancer Prevention Trial (SELECT).
The lowest risk group for developing prostate cancer had a 3.2 percent blood level concentration of omega-3 fatty acids, compared to 5.7 percent in the high risk group.
The results may come as a surprise to some, considering the number of positive health benefits that are associated with omega-3 fatty acids.
It remains uncertain why high concentrations of these fatty acids are associated with a heightened risk of prostate cancer.
Researchers say it is possible that omega-3 fatty acids are harmful because of they convert into compounds that can damage cells and DNA.
In conclusion, the finding suggests that high levels of omega-3 fatty acids can increase a man's risk of developing prostate cancer.
Written by Joseph Nordqvist