Omega-3 fatty acids likely NOT associated with prostate cancer

A weakly constructed study was reported recently that purportedly associated higher levels of omega-3 fatty acid blood levels and prostate cancer. See this CBS News report, for instance.

Lipid and omega-3 fat expert, Dr. William Harris, posted this concise critique of the study, exposing some fundamental problems:

First, the reported EPA+DHA level in the plasma phospholipids in this study was 3.62% in the no-cancer control group, 3.66% in the total cancer group, 3.67% in the low grade cancer group, and 3.74% in the high-grade group. These differences between cases and controls are very small and would have no meaning clinically as they are within the normal variation. Based on experiments in our lab, the lowest quartile would correspond to an HS-Omega-3 Index of <3.16% and the highest to an Index of >4.77%). These values are obviously low, and virtually none of the subjects was in “danger” of having an HS-Omega-3 Index of >8%. So to conclude that regular consumption of 2 oily fish meals a week or taking fish oil supplements (both of which would result in an Index above the observed range) would increase risk for prostate cancer is extrapolating beyond the data.

This study did not test the question of whether giving fish oil supplements (or eating more oily fish) increased PC risk; it looked only a blood levels of omega-3 which are determined by intake, other dietary factors, metabolism and genetics.


The authors also failed to present the fuller story taught by the literature. The same team reported in 2010 that the use of fish oil supplements was not associated with any increased risk for prostate cancer. A 2010 meta-analysis of fish consumption and prostate cancer reported a reduction in late stage or fatal cancer among cohort studies, but no overall relationship between prostate cancer and fish intake. Terry et al. in 2001 reported higher fish intake was associated with lower risk for prostate cancer incidence and death, and Leitzmann et al. in 2004 reported similar findings. Higher intakes of canned, preserved fish were reported to be associated with reduced risk for prostate cancer. Epstein et al found that a higher omega-3 fatty acid intake predicted better survival for men who already had prostate cancer, and increased fish intake was associated with a 63% reduction in risk for aggressive prostate cancer in a case-control study by Fradet et al). So there is considerable evidence actually FAVORING an increase in fish intake for prostate cancer risk reduction.

Another piece of the picture is to compare prostate cancer rates in Japan vs the US. Here is a quote from the World Foundation of Urology:


"[Prostate cancer] incidence is really high in North America and Northern Europe (e.g., 63 X 100,000 white men and 102 X 100,000 Afro-Americans in the United States), but very low in Asia (e.g., 10 X 100,000 men in Japan).”

Since the Japanese typically eat about 8x more omega-3 fatty acids than Americans do and their
blood levels are twice as high, you’d think their prostate cancer risk would be much higher...
but the opposite is the case.


Omega-3 fatty acids are physiologically necessary, normalizing multiple metabolic phenomena including augmentation of parasympathetic tone, reductions of postprandial (after-meal) lipoprotein excursions, and endothelial function. It would indeed make no sense that nutrients that are necessary for life and health exert an adverse effect such as prostate cancer at such low blood levels. (Recall that an omega-3 RBC index of 6.0% or greater is associated with reduced potential for sudden cardiac death.)

I personally take 3600 mg per day of EPA + DHA in highly-purified, non-oxidized triglyceride form (Ascenta Nutrasea liquid) that yields an RBC omega-3 index of just over 10%, the level that I believe the overwhelming bulk of data suggest is the ideal level for humans.

Comments (6) -

  • Jeff

    7/23/2013 10:56:11 PM |

    Can you advise where you get the Nutrasea Liquid that you mention you personally use above?.  I'm not finding any in the 3600mg range.  I couldn't find any where 2 doses equals that amount either.  Looking for high quality Omega 3's that are not sourced from Krill due to shell fish allergy.  Currently taking fish oil gel caplets of dubious quality.  Thanks in advance.

  • pickinthefive

    7/29/2013 5:58:45 PM |

    Hi Dr. Davis,
    A question I would have.  If you are at a known risk for prostate cancer, i.e. father or uncle's already have it, or in my case a reletively high PSA and symptoms of BPH, would it be wise to avoid the Omega 3's ?
    Thank you,
    Monty

  • Edwin

    8/14/2013 9:27:43 AM |

    So my eating a canned salmon sandwich for lunch most days which has about 1g of Omega3 (I take no supplements) should be safe?

  • Stephen in Anaheim

    8/15/2013 5:29:38 AM |

    I have to say that this is a great thing to read! In most dietary articles that I stumble across nowadays, I can find at least a paragraph or more on why people should be adding more Omega-3 fatty acids to your diet. In fact, I have read that Omega-3 can be quite beneficial for a number of medical conditions ranging from childhood asthma to fibromyalgia. It is scary to think that it could associated with a higher risk of prostate cancer, even though the underlying study was not well constructed.

  • Edward

    8/16/2013 3:08:29 AM |

    Dr. Davis,
    I take fish oil from a brand called "Carlson fish oil" it contains omega 3 fish oil 1,600. What would be the highest safest amount a person can take in Omega 3 in your experience from your patients and practice? What are your thoughts on the Linus Pauling Heart therapy which calls for a person taking at least 10 grams of vitamin C and 3-5 grams of Lysine in order to reverse plaque and heart disease? I have read the two time Nobel prize winner's books and his writings on heart disease are compelling. I would love the insight from an actual cardiologist with a practice to confirm what works and doesn't work.

  • Edward

    8/16/2013 1:19:06 PM |

    Dr. Davis,
    How much fish oil would you consider the highest and safest dosage for a person to take for heart disease and would the dosage a person who is healthy or heart problems differ?

Loading
Breaking news from the American College of Cardiology meetings

Breaking news from the American College of Cardiology meetings

The American Heart Association (AHA) was kind enough to send me an e-mail headlining the breaking news from the American College of Cardiology (ACC) meetings underway in Chicago:


ISAR-REACT 3
A Randomized, Double-Blind, Active-Controlled, Multi-Center Trial (ISAR-REACT 3) of Bivalirudin Versus Unfractionated Heparin in Troponin-Negative Patients Undergoing Percutaneous Coronary Interventions After Pre-Treatment With 600 mg of Clopidogrel

TRITON - TIMI 38 Stent Analysis
Prasugrel Compared to Clopidogrel in Patients With Acute Coronary Syndromes Undergoing PCI With Stenting: The TRITON - TIMI 38 Stent Analysis

Percutaneous Coronary Interventions in Facilities without On-Site Cardiac Surgery (NCDR)

(And four other similar reports)


Let's meld the ACC headlines with the financial headlines:

July 2, 2007
The Medicines Company announces reacquisition of all marketing rights to bivalirudin, anticoagulant growing in use for coronary angioplasty and related procedures. 2008 sales anticipated to be in the $15-20 million range, to grow to $90-110 million, a growth rate of 50% per year.


November 20, 2007
Drug manufacturing giant, Eli Lilly, vies for a portion of the $5 billion (annual revenues) oral anti-platelet market, now occupied by Plavix, with its newer, but questionably better, agent, prasugrel.


Growth of the coronary angioplasty (percutaneous coronary intervention, or PCI) doesn't ordinarily make headlines, but the performance of specific companies within the industry does. Angioplasty and cardiac device maker (inc. the drug-coated stent, Taxus), Boston Scientific, for instance, announced record sales of $8.537 billion for 2007, an increase of $536 million. How to grow this market? We could always hope for more people with heart attacks or other unstable symptoms. Or, we could . . . increase the number of hospitals capable of PCI! Brilliant.


The money behind this push for procedures is staggering. It drives enormous marketing efforts, pays Washington lobbyists, pays for many nice dinners and trips for doctors who engage in the system, and pays for very costly research.

And the AHA and ACC are kind enough to let us know about these great pieces of news.

Comments (1) -

  • Anonymous

    4/2/2008 12:28:00 PM |

    The Isar-React3 study supposedly was done by non-biased researchers in Germany.  Other articles have raised criticism of the findings.  Do not know the outcome of the meeting.

    Other drug research was also presented related to high blood pressure medicines.  Combination drugs with supposed less side effects were in the news.  All it takes is a study being presented at a prestigious group meeting to hit the news, and voila--consumers run to their doctors asking for it.  The articles don't say who is sponsoring the research and other ties....and side effects of some drugs aren't known until they've been on the market for a while.

Loading