Badly Flawed Study of Fish Oils Leaps to Wildly Unsupported Conclusions about Cancer

gel capsulesThe study’s authors showed similar biases in previous papers—yet the media keep stoking the flames without doing any serious analysis.
A new study from the Fred Hutchinson Cancer Research Center, led by Theodore Brasky, PhD, et al., has supposedly found a link between high concentrations of EPA, DPA and DHA in the bloodstream—the three anti-inflammatory and metabolically related fatty acids derived from fatty fish and fish-oil supplements—and an increased risk of prostate cancer: a 44% increased risk of “low-grade” prostate cancer, and a 71% increased risk of “high grade” (that is, aggressive) cancer, according to their report.
Brasky and his colleagues looked at two groups: their own cohort of 834 men diagnosed with prostate cancer, of which 156 had high-grade cancer; and, for comparison, the data and blood samples from 1,393 men of the same age range randomly chosen from the 35,500 participants in the prostate cancer SELECT trial. In looking at the analysis of the men’s blood samples, Brasky et al. found that men who had the highest amount of long-chain omega-3 polyunsaturated fatty acids (LCω-3PUFA) in their system had an increased risk of prostate cancer, compared to men with the lowest amount of LCω-3PUFA. At the same time, they found that omega-6 fatty acids were associated with lower risks of total prostate cancer.
Brasky and his colleagues had published a paper in 2011 indicating that DHA was positively associated with high-grade prostate cancer, but that trans-fatty acids (like those found in margarine and frying oils that contribute to heart disease) were associated with a decreased risk of aggressive prostate cancer. This new analysis seems to confirm their previous findings.
It’s like living in topsy-turvy land.
Brasky’s conclusions run contrary to almost every previous study on the subject. There are several prospective studies showing numerous benefits of omega-3 fatty acids in relation to cancer. In one, researchers investigated the effect of dietary fish intake among 6,272 Swedish men who were followed for thirty years. Men who ate no fish had a two- to three-fold increase in the risk of developing prostate cancer compared with those who consumed large amounts of fish in their diet. Similar studies have suggested lower prostate cancer risk associated with omega-3 fatty acids from fish in Japanese and Brazilian men.
An important Harvard study examined the link between dietary fish consumption and the risk of metastatic prostate cancer. The study involved 47,882 men over twelve years, and found that eating fish more than three times a week reduced the risk of prostate cancer but had an even greater impact on the risk of metastatic prostate cancer. For each additional 500 mg of marine fat consumed, the risk of metastatic disease decreased by 24%!
Let’s look at some of the problems with the study, both with the way the study was set up and with the conclusions reached by the researchers:

  • The group Brasky used for comparison in his study were participants in SELECT (the SELenium and vitamin E Cancer prevention Trial) conducted from 2001 to 2008. The $114 million study was trying to determine whether vitamin E (in the form of incomplete and synthetic alpha-tocopherol, one of eight forms of vitamin E that in nature work together) and selenium can prevent prostate cancer. This study was called to a halt when an early look at the data showed no benefit for the treatment. In this clinical trial there were slightly more prostate cancers in men taking alpha-tocopherol vitamin E alone, and slightly more diabetes in men taking only selenium. But neither finding was statistically significant, meaning these findings were likely due to chance.
  • No data was kept on the men’s dietary habits—neither among Brasky’s primary cohort, nor among the men in the SELECT trial. We do not know how much fish they might have consumed, or the quality or source of the fish oil supplements they took, or what other dietary supplements they might have taken or for how long. Perhaps the men with non-aggressive cancers took vitamins or other supplements; we just don’t know. Some fish (and fish oil supplements) can contain environmental chemicals that can contribute to prostate cancer. In other words, we have no idea where the omega-3 in the men’s systems came from—the study is silent on that issue, and that’s a huge problem.
  • The Life Extension Foundation’s Bill Faloon and his colleagues will be publishing their own rebuttal of Brasky’s findings shortly in Life Extension magazine, but they gave us a preview of their analysis. Their examination of the same trial data makes them suspect that that the men who had the slightly higher omega-3 levels may have already had a higher risk of contracting prostate cancer at baseline (they had higher PSA scores and a family history of prostate cancer). In other words, it’s possible they developed prostate cancer because of preexisting disease and/or genetic predisposition.
  • Faloon also points out that Brasky’s conclusions are based on only a single blood test, even though this was a long-term study. Plasma levels of omega 3 can change dramatically in the short term, so this study does not reflect a long-term incorporation of omega-3 into the patients’ cells and tissues. This is especially important when you consider that the difference in omega-3 blood measures associated with increased cancer risk were so trivial that if a man had just one salmon meal the night before, he could have wound up in the “higher” omega-3 group even if he never ingested omega-3 again.
  • Another significant factor: omega-3 plasma levels in the subjects were only about 40% of what would be expected in health-conscious people taking the proper dose of fish oil. It should be apparent that this report had no meaning for those who boost their omega-3 consumption through diet and supplements.
  • In an earlier study by the same authors, they reported that the risk for aggressive prostate cancer rose, then fell, then rose with increasingly high blood concentrations of DHA. This is not a consistent response—and the current study did nothing to clear up this strange ambiguity.
  • No mortality data is provided in Brasky’s analysis, so we really don’t know if men with prostate cancer would survive longer if they avoided omega-3s. However, as Bill Sardi points out, Japanese men consume the most omega-3 fish oil from dietary sources in the world, and they are recently reported to have a rising incidence in their risk for prostate cancer (likely due to better detection methods) but a declining risk for death from this very same disease. Aren’t better survival rates the gold standard for evaluating the success or failure of a treatment?

Despite the fact that the study showed no causal link between prostate cancer and fish oil supplementation or the presence of omega-3s in blood, the paper’s senior author made the following blanket statement in a press release: “We’ve shown once again that use of nutritional supplements may be harmful.” Have you ever heard such an absurd conclusion?
CAM physicians have mixed opinions on omega-3s from fish oil. Some, like respected California integrative doctor Robert J. Rowen, MD, recommend against fish oil because of the danger that it can oxidize once it reaches warm, oxygen-rich bloodstreams. These doctors recommend vegetable precursors (parental essential oils, e.g., flax oil). Others, like Dr. Jonathan Wright, recommend taking fish oils—but always with vitamin E (in the form of mixed tocopherols) to prevent against oxidative damage.
The pharmaceutical industry has developed their own omega-3 drugs, with more in the pipeline, some of which are in phase III of clinical trials. Since these drugs are only available by prescription, our concern is that studies like this will scare consumers away from supplementing sensibly, and will drive people to use the Big Pharma version when prescribed by a doctor.
Certainly the media plays a big role in that. Outlet after outlet merely parroted the press release and cobbled together one alarmist headline after another, with no context or critical analysis provided.
As we noted above, it is vital for natural health consumers who use supplements to do so wisely, in consultation with a qualified health expert. Understand what levels of each supplement is optimal for you and your condition. Use the most natural forms of any substance available: first, if you can, in food, and secondarily in natural, organic supplements. And always take them with the co-factors that make them safe and most able to be utilized by the body. As always, it’s a matter of balance, education, and following the advice of an experienced healthcare practitioner.


  1. My brother who did not eat fatty fish like salmon, mostly just fish fresh caught from inland lake waters, developed prostate cancer. Only one man, but significant for our family history.

  2. Ever since reading Pearson and Shaw’s book Life Extension back in the ’80s I was made aware of two things about fish oils. First that they are a polyunsaturated oil and that those type of oils rancidify quite readily. Second, is that the people who consume fish oils experience improved health. How can this be? How can a PUFA oil possibly be healthy and/or safe? Studies like these always make me wonder if taking fish oils is a wise thing to do, but the positive studies keep coming in as to the wonderful benefits of getting enough EPA and DHA in the diet. And, it isn’t very practical to eat fish everyday, cost wise and due to mercury levels, not to mention the question of how fresh is the fish. The proponents of eating fish as opposed to taking fish oils never consider that it is possible that the omega-3s in the fish they buy could be oxidized due to the way the fish was handled when it was caught and stored, plus the time it takes to get to the fish purveyors and put on their shelf. Any food or supplement has its risk/reward. I believe that so far the studies show that taking fish oils has much more reward than risk!

  3. Thanks for this article.
    I’d jumped to a similar conclusion, that this was another instance of media scare tactics. Good to have supportive evidence.
    I also didn’t realize that E as mixed tocopherals was useful taken with fish oils. I’ll add that to my routine supplementing.

  4. once again, the media jumps on any study however flawed that seemingly finds fault with a food supplement, even though numerous studies and human trials have proven otherwise. It just seems too boring for a news outlet to report more good news about supplements. Unfortunately, many men will be advised by physicians with little knowledge to avoid fish oils to the detrement of their health. As you point out, there is a big difference in whole food supplements with all the components and an isolate. This study will do a lot of harm.

  5. Talk about STUPID!! If anyone even starts to believe this garbage that fish oil (omega-3 fatty acids) can be BAD for you, look very thoroughly at the people in Japan! They live almost completely on fish, having a huge amount of omega-3’s in their daily diets, and if you look at their health as a country, it blows all others out of the water. No heart, cholesterol, stroke, etc. All basically because of this awesome, God-given oil!! Don’t believe every study you read…some are very tainted. Use your common sense, and also, your computer, to research for yourself. Just looking at places like Japan, you can clearly see that fish oil is NOT the bad thing this study says it is.

  6. Thanks again ANH, once again certain individuals are trying to pull the wool over our eyes but thanks to you and other health freedoms organisations we are remaining well informed!

    1. So-called science gets sillier. Check the analysis of a can of wild Alaska salmon, bone and skin included. A fish oil pill contains roughly the same amount of fatty acid as a few ounces of salmon. So are these folk telling us its not safe to eat salmon? If not then they should be telling us why their study came up with such an unexpected result. Lack of common sense is a barrier to doing anything useful in science and we sure are seeing a lot of absent common sense recently. The data in the study could be valid but they require an explanation such as was the fish oil in the capsule rancid? Claiming fatty acids are in effect toxic based upon these results is just plain science nonsense. What has gone wrong with our educational system that allows the publication of such conclusions by people claiming an education to the level of a PhD.

      1. Very little if anything in that or similar-source of articles relates to science. I’ve studied Evidence Based Nutrition course in my college, going through the detailed analysis after analysis on how the studies on supplements were designed, conducted, calculated and concluded. It’s bitter and painful to realize and it’s hard to believe what kind of “science” sometimes rules out for our health “to be or not to be”.
        A sample of such an unfortunate study was the notorious Seven Countries Study conducted by Ancel Keys who demonized and condemned saturated animal fat for the entire generation, which, as a result of his conclusions, was put on a polyunsaturated oils and margarine.
        The very design of many trials and studies does not allow a hope for a true scientific result. I’m more then sure that the fish oil in the studies (all the batches for all the population in the trial, and throughout the length of the studies) were ever continuously tested for the rancidity and for the dioxin levels), neither the individuals chosen to be studied for fish-oil-supplementation were studied well as to their precise health history, background, and dietary habits while consuming that fish oil. What kind of fish was used for the supplements production, from which region, who was the producer of them?
        Do you know that all the vit. E supplements (any oil-based ones) sit in a vitamin store without any refrigeration whatsoever? Many times I’ve learned them to be rancid, with the expiration date, yet, in two years. So the quality of the supplements and their freshness determines whether they benefit or harm you. My believe is that the process of oils encapsulation at manufacturing them as supplements involves the level of temperatures that are causing their rancidity, which is then masked with some pleasurable odorants like in production of the vegetable / seeds / nuts oils.
        Evil things are done in the name of “science” – sometimes altered and falsified – when one giant, Pharma, wrestles with another one, Supplements, for the market of billions of money.

  7. This study didn’t mention if the fish oil was ”heavy metal-free” too! if the fish oil wasn’t molecularly distilled, it may cause cancer because it contains those toxic metals. The harm comes from the heavy metals and not from the fish oil.

    1. Oxidation of PUFAs creates radicals in a chain reaction. Vitamin E oxidizes to break the chain and is recycled by vitamin C. Not all of the vitamin E is recovered. Enough PUFAs in cell membranes depletes Vitamin E.
      Selenium-containing enzymes glutathione peroxidase and thioredoxin reductase can substitute but are sensitive to low intake or mal-absorption of selenium.
      The ALA in linseed oil oxidizes in air to produce a yellow rubbery substance called paint. The EPA and DHA in menhaden oil are also used in fast-drying paints. Menhaden oil becomes rancid so quickly that it is not safe for consumption.
      In the body PUFAs can be oxidized by a peroxidase to become a yellow paint-like substance called ceroid. When deposited in fat cells ceroid causes an inflammation called steatitis or yellow fat disease.
      Excess consumption of PUFAs can reduce Vitamin E levels below the limits of detection especially when selenium is low. Vitamin E deficiency can cause a degeneration of skeletal and cardiac muscles called nutritional muscular dystrophy or white muscle disease probably via loss of mitochondria. Most often seen in livestock grazing on selenium-deficient land, it also occurs in dogs and cats that have been fed too much fish and/or vegetable oil without supplemental vitamins and minerals.
      A similar condition called brown bowel syndrome occurs more often in humans than livestock. The intestines degenerate with deposition of a brown residue from oxidized cell membranes called lipofuscin. It appears to combine the pathologies of steatitis and nutritional muscular dystrophy and may not fully resolve after vitamin E supplementation.
      Coming full circle, brown bowel syndrome is thought to be responsible for the high death rate from malignancy in patients with celiac sprue and chronic pancreatitis.
      An excess of PUFAs appears to increase cancer risk. The recent study finds increased risk at dosages previously thought safe and finds it for n3 but not n6 PUFAs. That suggests we wait for peer review and replication.

  8. it is a sorry state when individuals(without scientific study) come forward with negative information on such nutritional items as fish oils.By doing so they cast doubts into peoples minds of well establishedand scientifically studied issues important to general health.

  9. now tomorrow you`ll send me an email telling me how much mercury is in fish and i should stay away from it.

  10. This is one more example of the deleterious impact of money, and the “halo effect” of professional credentials, on science. We’re all supposed to be impressed that someone with the initials “MD” after their name published a poorly constructed study that “proved” the harmfulness of a substance ingested by millions of people daily? Gimme a break!
    Have you noticed that, in EVERY case of studies such as this, NO mention is made of who funded it? I’ll give you three guesses, and the first two don’t count! Big Pharma is out to destroy the natural products industry, with the help of their ignorant lackeys in the mainstream media (who, by the way, are just as beholden to Big Pharma dollars as the researchers are).
    Only when there are legal requirements in place to force these people to disclose the source of their funding, and penalties for non-compliance, will their true motivation be evident to the general public. Until then, thanks to ANH-US for its continuing pursuit of the truth, and the protection of our right to bodily integrity.
    Peter McCarthy, ND
    Chair, Texas Health Freedom Coalition

  11. USA/FDA corruption is total and complete ……Similar to Germany in the 30’s until the end of WWll ,,, The only difference is here it’s all about the money and controlling it…For proof watch the Burzynski video …………

  12. Such a surprise that the only people who complain about the research are those who have something to lose financially. The research was sponsored by the national cancer institute and the office of dietary supplements. It’s reasonable to believe that the scientists were doing their job and its not an anti-supplement conspiracy.

    1. Consider the source… your so-called “corporate media”. This study is ridiculous.

  13. What everybody (including the ANH article) seems to be overlooking here is that no actual fish oil was KNOWN to have been used by any of the study participants. This study was set up to examine Vit E and Selenium, and did not “control for” (in other words, keep track of or even ask) about diet or supplement use.
    So – everybody seems to be assuming that subjects were using fish oil, without ever knowing that for sure, or as pointed out above, how much/ what form IF it was being used. Both the study and this article also fail to mention that there are other known factors that can raise DHA blood levels, including low fat diets.
    I’ve read several articles dissecting the study that perhaps you’d like to look at, too. Here are a couple of them:

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