Mercury levels in fish by U.S. Geological Survey Fact Sheet
I received an email from a concerned patient who consumes omega 3 fish oil every day as part of his nutritional-supplement program to prevent heart disease. He was concerned because he saw an article in the paper reporting fish oil increases risk for prostate cancer. The data in the fish oil-prostate study was published in 2011 by Theodore Brasky of Ohio State University Comprehensive Cancer Center. A new report on this same data just came out in an article July 10 in the Journal of the National Cancer Institute.
Above Image: photo of fish courtesy of USGS.
In Dr Brasky's study, the type of fish or fish oil consumed was not controlled. The study did not use any particular brand or quality of fish oil; instead, a questionnaire was sent to the participant, and blood levels of omega-3 fatty acids were measured in the patients. So, it is highly likely that the fish consumed or the fish oils used varied in quality and some or all may have been contaminated with carcinogenic chemicals.
Serum Omega-3 Fatty Acid Level -- Surrogate Marker for Carcinogenic Contaminants in Fish
So, in my opinion, the Brasky Fish Oil study
proves that carcinogenic chemicals in fish cause cancer. Measuring the
amount of omega-3 fatty acids in the blood is a surrogate marker for contaminated
fish and fish-oil consumption. These contaminants cause cancer. We already knew that. Perhaps the most studied carcinogenic chemicals that accumulate in fish are PCBs and dioxins, which are known carcinogens.
Does Our Food Cause Cancer?
We normally eat food in order to survive and stay healthy. Fish is one of the foods we humans have consumed for millions of years. Eating a fish is no more carcinogenic any than any other food on our plate. It's the contamination by industrial chemicals in our food that is carcinogenic. So the correct answer is that fish oil does not cause cancer. Carcinogenic chemicals that contaminate the fish DO CAUSE cancer.
Self-Censorship in the News
If you read the news reports, you will notice a form of self-censorship. The journalists avoid mentioning the fact that fish and fish oils are contaminated by environmental pollutants that are carcinogenic. Apparently that might annoy their corporate sponsors who are the source of the environmental pollution.
Why Take Fish Oil in the First Place?
The main reason most of my patients take fish oil is the benefit for cardiovascular-disease prevention. A recent Harvard study by Mozaffarian in the Annals of Internal Medicine showed that higher omega-3 fatty-acid levels in the blood were associated with a 20-30% reduction in mortality from cardiovascular disease.
Pure Omega 3 Oils Avoid Carcinogenic Contamination
My recommended fish-oil supplement is the DHA Ultimate. This is a solvent-free, supercritical CO2-based extraction fish-oil concentrate. The manufacturer uses low temperature, oxygen-free processing to prevent oxidation reactions. Each batch of fish oils is third-party tested to assure the product is free of heavy metals, dioxins/furans, dioxin-like PCBs and PCBs, etc.
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