The potential clinical implications of a study recently published in the Journal of the National Cancer Institute by Brasky et al. on omega-3 fish oil and prostate cancer risk should be contemplated with careful consideration of the various limitations of the study, according to a commentary published in August in the Natural Medicine Journal.
The commentary, co-authored by the Council for Responsible Nutrition’s (CRN) Duffy MacKay, N.D., vice president, scientific and regulatory affairs, and CRN Senior Scientific Advisory Council Vice Chair Barry Ritz, Ph.D., vice president, scientific and regulatory affairs, Atrium Innovations, noted that “The study’s design is well-suited to identify correlations that should be interpreted in context, with consideration of biological plausibility and other clinical trials, which should have modified the author’s provocative and oddly strong conclusions.”
Drs. MacKay and Ritz explained that the study was an epidemiological study—which is meant to generate a hypothesis, not establish a cause-and-effect relationship—intended to look at the relation between selenium and vitamin E supplementation on prostate cancer risk. At no point during the study were the subjects given fish or fish oil supplements. Also, dietary intake of fish or fish oil supplements was not documented, creating no data to back the conclusion that supplemental omega-3 fats are correlated to an increase risk of prostate cancer.
Additionally, Drs. MacKay and Ritz noted that the conclusion of the study contradicts the recommendations of reputable health organizations as well as the greater body of scientific evidence which demonstrates the established benefits of both fish and fish oil, saying this study “should not change clinicians’ dietary recommendations or prescribing patterns.”
“With nearly a fifth of all U.S. adults taking omega-3 fish oil supplements each year, it’s not only essential to counter balance the consumer headlines that often make sweeping conclusions,” said Dr. MacKay, “but it’s equally important to engage the scientific and clinician communities in a dialogue so that the science is critically interpreted. Part of our role at CRN is to make sure the science is interpreted fairly.”