What You Should Know About Omega-3 Fatty Acids and Prostate Cancer

A study was published in the J. Natl. Cancer Institute suggesting a link between omega-3 polyunsaturated fatty acid (omega-3s) intake and increased risk of prostate cancer (Brasky et al., 2013). Many questions have been asked regarding whether men should continue to use omega-3 supplements. Numerous benefits have been associated with the use of omega-3s including positive effects on cardiovascular health, perinatal health and fetal formation, cognitive function, and uterine cancer (Mazza et al., 2007; Wang et al., 2006). The data for the recent article (Brasky et al., 2013) were derived from an epidemiological study meant to generate a hypothesis, not establish a cause-and-effect relationship, and was designed to address selenium and vitamin E supplementation on prostate cancer. Subjects were not given fish or omega-3 supplements as part of the research protocol, nor was dietary intake of fish or omega-3s documented, creating no data to back the conclusion that supplementing omega-3s correlated with an increased risk of prostate cancer. The authors were quick to brand dietary supplements as the cause although there was no evidence that anybody in the study took omega-3 dietary supplements. The study demonstrated no cause-and-effect relationship, and it only purported to show an association between higher plasma levels of omega-3s and those identified as having an increased risk of prostate cancer. A major flaw in the report of Brasky et al. (2013) is the fact that what they refer to as a high omega-3 blood level is very near the average of a normal unsupplemented population (Cao, Schwichtenberg, Hanson, & Tsai, 2006), a population that neither supplements with omega-3s nor consumes fatty fish. The difference between what the authors consider low and high levels is insignificantly small physiologically with the high level being about 40% of the level expected in an individual who daily consumes an omega-3 supplement. Furthermore, a one-time determination does not reflect long-term incorporation of omega-3s into tissues and cells. As a consequence, the subjects considered to be in the highest quartile of omega-3