Industry Defends Omega-3 Supplements Against Cancer Study

WASHINGTONThe Natural Products Association (NPA), Global Organization for EPA and DHA Omega-3s (GOED) and Council for Responsible Nutrition (CRN) challenged conclusions reached in a new study suggesting omega-3 supplements can increase the risk of prostate cancer (J Natl Cancer Inst. 2013 Jul 10).

Cara Welch, Ph.D., NPA senior vice president of scientific and regulatory affairs, said the study only discusses a correlation between cancer and omega-3 supplementation, and correlation does not equal causation.

"Simply put, there is nothing in this study that raises any red flags for NPA," Welch said. "We welcome the Journal of the National Cancer Institute to continue publishing research on the health effects of omega-3s because we're confident the benefits outweigh risks. Additionally, the authors' jump to blaming supplements for these results is irresponsible, at best, when the study didn't include any information about how the omega-3 intake was achieved."

John Shaw, NPA executive director, added that omega-3 supplements offer a variety of health benefits, from heart health to assisting in prenatal care.

Omega-3 supplements are used every day by consumers all across the country who wish to reap the crucial health benefits these products provide," he said.

GOED also commented on the research results, pointing out the study was not specifically designed to research the exact relationship between omega-3s and prostate cancer. If findings were true, "prostate cancer would be rampant in any country with high seafood consumption," which is not the case, the organization added.

"While any recommendation for supplementation should consider any associated risks, we believe the authors' conclusion is irresponsible and blatantly ignores the totality of the scientific evidence that has been collected over multiple decades regarding the health benefits of marine omega-3 fatty acids," GOED said.

Duffy MacKay, N.D., CRN vice president, scientific and regulatory affairs, said the benefits of omega-3s have been well-established, and the new study does not change those recommendations or the importance of the nutrient.

"While we encourage researchers to continue to study omega-3 fatty acids with an open mind, it is counterproductive when studying nutrition for researchers to promote their study as if it were the only piece of research that counts," MacKay said. "In this case in particular, it is especially disingenuous for the researchers to make the kinds of assertions weve seen in the press, given their results are in stark contrast to previous epidemiologic studies that not only demonstrate no correlation between omega-3 consumption through fish and/or supplementation and the risk of prostate cancer, but in many cases also showed a protective effect against prostate cancer."

MacKay also said researchers were too quick to blame dietary supplements. No evidence shows participants in the study took fish oil supplements, so the study does not demonstrate cause and effect.

This study could have simply been measuring a biomarker reflecting recent intake of fish or fish oil supplements in a group of high-risk cancer patients told to increase their EPA and DHA levels, as compared to a group of non-cancer patients that had not been told to consume more EPA and DHA, MacKay added.

"Plasma levels of EPA and DHA reflect very recent intake and are considered a poor biomarker of long term omega-3 intake, especially when compared to red blood cell levels, which reflect medium term intake," he said. "A single fish oil dose (or hearty serving of fish at lunch) results in a greater than 100-percent increase in plasma omega-3 levels. So looking at plasma levels in healthy and sick people may only provide insight into the recent habits of these individuals."

The American Heart Association, the World Health Organization (WHO), the U.S. Institute of Medicines Food Nutrition Board (IOM FNB) and the 2010 Dietary Guidelines all have current policies advising Americans to eat more fatty fish to get the benefits of omega-3 fish oils, MacKay said.

Previous research indicates omega-3 fatty acids appear protective against advanced prostate cancer and may impact prostate inflammation and carcinogenesis through the COX-2 enzymatic pathway.