A large-scale study suggests that ingesting high levels of omega-3 may be linked to increased risks of developing prostate cancer in men.
The new prospective study of data and specimens collected from male participants of the Selenium and Vitamin C Cancer Prevention Trial (SELECT)—a large-scale, randomized, placebo-controlled trial conducted in Europe—sought to test if selenium and vitamin E, either combined or separately, minimized risks for developing prostate cancer, according to NutraIngredients.
The researchers used SELECT data to analyze blood plasma omega-3 levels for the 834 men diagnosed with prostate cancer (156 were diagnosed with high-grade prostate cancer) and the 1,393 men in the comparison group, or placebo group, according to NutraIngredients. The men were randomly selected from a group of 35,500 SELECT participants. The study appears in the Journal of the National Cancer Institute.
This study confirmed prior research findings and found that high blood concentrations of long chain omega-3 polyunsaturated fatty acids (PUFAs) were associated with increased risks of developing aggressive prostate cancer by 71 percent, according to NutraIngredients. Also, a 44 percent increase in risks for low-grade prostate cancer and a 43 percent increased risk for all prostate cancers was seen.
“We’ve shown once again that use of nutritional supplements may be harmful,” said senior study author, Dr. Alan Kristal, from the Fred Hutchinson Cancer Research Center, according to NutraIngredients. Dr. Kristal noted that the results of both the prior 2011 study and this study are surprising given that omega-3 fatty acids have long been believed to offer numerous positive effects due to their anti-inflammatory properties. “The consistency of these findings suggests 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 team wrote, according to NutraIngredients.
“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 recurrence,” said co-author Dr. Theodore Brasky, of the Ohio State University Comprehensive Cancer Center, NutraIngredients wrote. Dr. Brasky, lead author of the 2011 study added, “It’s important to note, however, that these results do not address the question of whether omega-3s play a detrimental role in prostate cancer prognosis.”
We previously noted that, according to MSNBC, the double blind, placebo controlled trial format is well respected and considered to be the highest scientific evidence standard.
The National Cancer Institute funded the SELECT trial. By 2008, the study was halted when no benefit was seen; however, the team continued to monitor the participants and found that after four years of follow-up, vitamin E increased prostate cancer risks by 17 percent in men taking a daily dose of 400 IUs, according to the report’s conclusion. The 2011 study results were published in the Journal of the American Medical Association. At the time of the 2011 study, the researchers believed selenium might also reveal negative reactions.