Hide this
Omega-3

Story at-a-glance +

  • A recent case-cohort study found that men with higher blood concentrations of omega-3 fat had a 44 percent increased risk of developing low-grade prostate cancer compared to those with the lowest levels
  • Specifically, higher blood levels of the omega-3 fat DHA correlated to higher prostate cancer risk, while no correlation was found for EPA and ALA. They also had a 71 percent higher risk of developing high-grade prostate cancer
  • The elevated blood levels of DHA found in the featured study is not necessarily indicative of higher fish consumption. In fact, low-fat diets can increase DHA levels in much the same way omega-3 supplementation can
  • While the researchers warn that fish oil supplements may be dangerous based on their findings, this study cannot show causation. Furthermore, no fish oil supplements were actually given as part of this study
  • Foods rich in omega-3 fats have previously been shown to prevent prostate cancer from spreading, and one recent meta-analysis found that fish consumption was associated with a 63 percent reduction in prostate cancer-specific mortality
 

Absurd Study Claims Omega-3 Fats Raise Prostate Cancer Risk

July 31, 2013 | 235,266 views
| Available in EspañolDisponible en Español
Share This Article Share

By Dr. Mercola

Omega-3 rich fish oil is one of the most well-researched substances on the market. Its wide ranging health benefits have been repeatedly proven, and animal-based omega-3 is one of the few supplements I recommend for virtually everyone to improve overall health.

But omega-3 fat, naturally found in salmon and krill, which are both excellent sources, has received some undeservedly bad press coverage lately. You may have seen some of the following headlines:

  • Link Between Omega-3 Fatty Acids and Increased Prostate Cancer Risk Confirmed (Science Daily1)
  • Omega-3 Supplement Taken By Millions 'Linked to Aggressive Prostate Cancer' (Huffington Post2)
  • Men who take omega-3 supplements at 71% higher risk of prostate cancer (NY Daily News3)
  • Omega-3 supplements may trigger prostate cancer (Nursing Times4)
  • Hold the salmon: Omega-3 fatty acids linked to higher risk of cancer (Time Magazine5)

These headlines are perfect examples of gross misreporting of science by the media, and it is instances like this that demonstrate why you cannot trust the conventional press to keep you informed about health. In the words of Jonny Bowden,6 PhD, CNS, the media’s reporting on this particular study is “disgraceful, incompetent, and scientifically illiterate.” I couldn’t agree more.

'Omega-3 Fats Involved in Prostate Tumorigenesis,' Researchers Claim

The study raising all this hoopla was published in the Journal of the National Cancer Institute7 on July 10. This case-cohort study8 examined associations between omega-3 levels in blood and prostate cancer risk among participants in the "Selenium and Vitamin E Cancer Prevention Trial," also known as SELECT.9

The researchers concluded that men with higher blood concentrations of animal-based (marine-derived) omega-3s had a 44 percent increased risk of developing low-grade prostate cancer compared to those with the lowest levels.

Specifically, higher blood levels of the omega-3 fat DHA correlated to higher prostate cancer risk, while no correlation was found for EPA and ALA. They also had a 71 percent higher risk of developing high-grade prostate cancer.

The “grade” refers to the level of abnormality found in the cancer cells.10 The more abnormal the cells appear, the higher the grade of the cancer. Based on these correlations, the researchers concluded that “these fatty acids are involved in prostate tumorigenesis.” But just how did they reach that conclusion?

According to Time Magazine:11

“The study measured omega-3 blood levels in the participating men, and did not include information on the volunteers’ eating habits, so researchers could not differentiate between the effects of fatty acids from fish from those of supplements. However, the overwhelming majority of the participants did not take fish oil supplements.

Based on the results, [lead author, Theodore] Brasky says that men with a family history of prostate cancer should discuss with their doctor whether fish oil supplements are safe for them, since these pills tend to contain concentrated doses of omega-3.

Supplements contain between 30% to 60% of a serving of fish, and if a fish oil supplement is taken every day, that adds up to a lot of daily fish oil. Brasky also suggested that men cut down on their fatty fish intake, though not eliminate it entirely.”

Folks, this is some of the most absurd advice I’ve seen in a long time. How they could possibly come to the conclusion that omega-3 supplements might be dangerous based on this study is a mystery in and of itself. Correlation is not the same as causation, first of all.

Secondly, no omega-3 supplements were actually given in this study. In fact, most participants reportedly did not take them. Another immediate tip-off that something’s awry is the finding that participants who had the highest levels of trans fats in their blood had the lowest risk for prostate cancer... As Dr. Bowden writes in his Huffington Post12 rebuttal:

“How do you explain the fact that reporter after reporter and news outlet after news outlet conveniently equated higher blood levels of DHA with 'fish oil supplement taking?'

There’s almost no other explanation other than a strong anti-supplement bias and a desire for shocking headlines. And any doubt about the objectivity of the researchers should have been abandoned after one of them—Dr. Alan Kristy—told reporters,13 'We’ve shown once again that use of nutritional supplements may be harmful.'”

Indeed, Dr. Kristy sounds like a spokesperson for Senator Durbin’s hypocritically idiotic supplement bill, which threatens the supplement industry by granting the FDA more power to regulate supplements as if they were drugs, potentially putting supplement companies out of business.

Do Omega-3s Raise Men’s Prostate Cancer Risk? Hardly!

Foods rich in omega-3 fats have previously been shown to prevent prostate cancer from spreading. One such clinical study (opposed to the featured study, which was observational and therefore cannot establish causality) was published in the British Journal of Cancer14 in 2006. This study found that while omega-6 fats (the kind found in most vegetable oils) increased the spread of prostatic tumor cells into bone marrow, the spread of cancer cells was blocked by omega-3 fats, suggesting that a diet rich in omega-3 fats could potentially inhibit the disease in men with early stage prostate cancer.

A more recent meta-analysis15 of available research, published in 2010, found that fish consumption was associated with a 63 percent reduction in prostate cancer-specific mortality, even though no association between fish consumption and a significant reduction in prostate cancer incidence could be found. GreenMedInfo.com16 recently discussed this topic as well, listing a number of additional studies that have shown fish/fish oil/omega-3 to be beneficial against prostate cancer.

As pointed out by Denise Minger,17 previous research18 has shown that the higher blood levels of DHA found in the featured study is not necessarily indicative of higher fish consumption. In fact, low-fat diets can increase DHA levels in much the same way omega-3 supplementation can. According to previous research:

“Plasma phospholipid fatty acids have the potential to function as a surrogate measure of the potential effects of diet on a whole range of cell membrane lipids... This difference in fatty acid levels after the consumption of similar proportions but varied content of fatty acids suggests competition among the lipid series [(n-3), (n-6), (n-7) and (n-9)] for the enzymes of elongation and desaturation.

When the relative supply of (n-3) fatty acids is abundant, these fatty acids are preferentially desaturated and elongated relative to (n-6) fatty acids)...

In summary... free fatty acid compositions are responsive to total dietary fat content. Specifically, the consumption of a low fat diet promotes an increase in the level of total and highly unsaturated long-chain (n-3) fatty acids and a decrease in the total (n-6) content of plasma phospholipid and cholesteryl ester fatty acids. The observed modifications in phospholipid and cholesteryl ester fatty acids in response to a low fat diet are similar to those observed when (n-3) fatty acids of plant or animal origin are fed.”

Why DHA Levels in Featured Study May Be Meaningless...

Furthermore, the featured study reported DHA levels based on percentage of total fatty acids rather than the absolute value, which in and of itself can be quite misleading,19 as it actually obscures any real differences. Dr. Bowden illustrates the dilemma well with the following analogy:

“Would you like 90 percent of all the money Mr. Jones has or 10 percent of all the money Mr. Smith has?”

How could you possibly tell how much money those percentages of total represent, unless you know how much money Mr. Jones and Mr. Smith each have to begin with? As explained in a 2009 commentary published in the American Journal of Clinical Nutrition,20 the only time percentage of total might be meaningful is when the total fatty acid content is identical for all subjects, which it undoubtedly was not in this case.

As stated by Dr. Bob Roundtree, MD:21

“Considering the extensive body of literature that supports the anti-inflammatory effects of omega-3 fatty acids, there is no credible biological mechanism, nor is one suggested in the article, that would explain why these essential fatty acids might increase tumorigenesis.”

Confounding Factors Ignored

Another problem with studies looking at correlations only, is that the factor you’re looking at may only be a minor player, or completely irrelevant, compared to other factors. For example, in this case:22

  • 53 percent of the subjects with prostate cancer were smokers
  • 64 percent of the cancer subjects regularly consumed alcohol
  • 80 percent of the cancer subjects were overweight or obese

According to a 2011 study published in PLoS One,23 aggressive prostate cancer was associated with obesity. More recently, a cohort study published in Cancer Epidemiology, Biomarkers & Prevention24 in April of this year found that men who were overweight or obese increased their risk of prostate cancer by 57 percent—a percentage that falls right smack in the middle of that 44-71 percentage range attributed to high DHA serum levels in the featured study. And this association between obesity and prostate cancer held for all cases— low-grade and high-grade, early stage and late, nonaggressive and aggressive prostate cancer.

Krill Oil vs. Fish Oil: What's the Better Source?

From my perspective, based on medical experience and overwhelming scientific evidence, making sure you’re getting enough omega-3 in your diet, either from wild Alaskan salmon or a high-quality omega-3 supplement like krill oil, is absolutely crucial for your optimal health. While a helpful form of omega-3 can be found in flaxseed, chia, hemp, and a few other foods, the most beneficial form of omega-3 -- containing two fatty acids, DHA and EPA, which are essential to fighting and preventing both physical and mental disease -- can only be found in fish and krill.25

Unfortunately, nearly all fish, from most all sources, are now severely contaminated with toxic mercury, which is why I have amended my previous recommendations to consume fish on a routine basis. It's simply not advisable for most people any longer. About the only exception to this rule is wild-caught Alaskan salmon. This is really the ONLY fish I’ll eat on a regular basis, and the only one I feel comfortable recommending as a good source of healthful fats. AVOID farmed salmon, as they contain only about half of the omega-3 levels of wild salmon. Farmed salmon may also contain a range of harmful contaminants, including environmental toxins, synthetic astaxanthin, and genetically engineered organisms from the grain feed they’re given.

My latest recommendation for a source of high quality omega-3 fats is krill oil. The omega-3 in krill is attached to phospholipids that increase its absorption, which means you need less of it, and it won't cause belching or burping like many other fish oil products. Additionally, it naturally contains astaxanthin, a potent antioxidant—almost 50 times more than is present in fish oil. This prevents the highly perishable omega-3 fats from oxidizing before you are able to integrate them into your cellular tissue. In laboratory tests, krill oil remained undamaged after being exposed to a steady flow of oxygen for 190 hours. Compare that to fish oil, which went rancid after just one hour. That makes krill oil nearly 200 times more resistant to oxidative damage compared to fish oil!

When purchasing krill oil, you'll want to read the label and check the amount of astaxanthin it contains. The more the better, but anything above 0.2 mg per gram of krill oil will protect it from rancidity. To learn more about the benefits of krill versus fish oil, please see my interview with Dr. Rudi Moerck, a drug industry insider and an expert on omega-3 fats.

Thank you! Your purchases help us support these charities and organizations.

Food Democracy Now
Mercury Free Dentistry
Fluoride Action Network
National Vaccine Information Center
Institute for Responsible Technology
Organic Consumers Association
Center for Nutrtion Advocacy
Cornucopia Institute
Vitamin D Council
GrassrootsHealth - Vitamin D*action
Alliance for Natural Health USA
American Holistic Veterinary Medical Foundation
The Rabies Challenge Fund
Cropped Catis Mexico