Prostate Cancer and Omega-3 Fats

Howdy folks!

This is going to be quick and likely full of type-o’s, I just want to get this posted and I’m not even going to pester Squatchy with a proof-read, so please accept it, warts and all. I’ve been hammering on the nutrition cert and the only way I get any work done on that is dropping off the map. Multi-tasking seems good for cortisol production and LOOKING busy, but not getting a damn thing done!

Ok, so lots of hub-bub about some recent papers implicating N-3 fats and increased prostate cancer risk. Here are two papers which largely cover the same material, which I will refer to here in a bit (serum fatty acids prostate cancer risk1, plasma FAs and prostate cancer2). Luckily, some other folks have entered the fray, so I do not need to re-hash what type of study this is, and one of the main shortcomings of the research: this is correlation, not a demonstration of mechanistic causation. Check out this piece from which breaks all that down in a very accessible way. The main takeaway from this is typical of how the media runs wild with research: Headlines are saying fish oil gives you prostate cancer. As points out, even IF this is the case, the current batch of literature is not anywhere near sufficient to make that statement, just keep that in mind.

These papers involve a LOT of data analysis…I’m going to look a bit at some of the methodology that went into the fatty acid analysis, but this section from the Results section of paper 1 is worth looking at first:

“Table 1 gives baseline demographic and lifestyle characteristics of study cases and controls. Compared with controls, high-grade cases were significantly older and were more likely
to have been randomized to the finasteride treatment arm. Low-grade cases were less likely than controls to have a history of diabetes.”

I don’t have the time to go back trough this and re-crunch the data (perhaps a Denise Minger or Chris Masterjohn could tackle this?) to look at how these factors were addressed. What this is saying: the worst cancers happened in the oldest people, the less severe cancers occurred in people with less frequency of diabetes. We know age increases cancer risk, we also know insulin resistance and oxidative stress (like that seen in Type 2 DM) is a potent stimulus for endoderm derived epithelial cancers like those seen in breast, colon and prostate. So, I’m honestly scratching my head a bit about how these vectors were addressed in the whole picture. And again, as the piece from Examine makes clear, we do not know if elevated N-3 are: causing increased prostate cancer, a consequence OF prostate cancer, or simply correlative and have no dog in that fight at all. Given what we know about the effects of N-3’s (and N-6’s) and inflammation, oxidative stress and immune modulation, I’m not at all surprised if they do have some role in all this (be it positive or negative, depending on the situation) but these papers are at best preliminary work, necessitating more work.

Some thoughts and concerns in no particular order:

1-We do not seem to see the “negative” effects of N-3 consumption from whole foods. In fact consumption of N-3’s is called a “Cancer Reducing Diet” in other corners of the research world and interwebz. Again however, another correlative study.

2-Are additional N-3’s potentially harmful in a sick, inflamed, insulin resistant population? Seems a safe bet, and as to my point above, I’m not sure the researchers did a thorough job of accounting for those factors. Perhaps they did…I have not and will not have the time to crunch that data…hopefully someone else will. But this is a really important question.

3-It would appear no correlation with prostate cancer and saturated fats was found (sorry vegans). The headlines seem equally able to say “saturated fat does NOT increase prostate cancer risk.”

4-One thing that really concerns me is when the researchers were looking at trans fats (TFA’s) they lumped industrial, hydrogenated TFA’s in with those derived from the activity of ruminants, specifically the many isomers of conjugated linoleic acid (CLA). CLA has known anti-tumor activity, yet the researchers give it the same category as hydrogenated seed oils. CLA has been in our biosphere for a “looong time” and shows a variety of benefits…that the researchers missed this point makes me wonder a little about many other assumptions.

5-Is this the oxidative stress from rancid fish oil capsules? I never did get a sense from the literature how they delineated where the N-3 were coming from, but this could certainly be an issue. What the fish oil manufacturers do to mitigate this issue is add antioxidants like vitamin E to the capsules. But…all of these studies seem to implicate supplemental vitamin E as increasing cancer potential (beta carotene in smokers too).  Again, I’d really need to dig around in the data to see how or if any of this was accounted for.

6-The difference between the low vs high risk cancers seems to boil down to the equivalent of one vs 2 meals containing salmon per week. Is this a complete artifact of the data analysis? Only important in sick, inflamed individuals? We don’t know, but that seems an amazing razors edge to walk.

7-This whole story reminds me somewhat of the China Study. In that story, mice were fed casein protein, a piss-poor lab chow diet (already known to cause disease in our murine pals) and aflatoxin, a potent carcinogen. In other words, a diet completely divergent from what rodents would eat in the wold. Now, we wait and see what the cancer rates are in these critters relative to a low-protein control. What is reported is the high-protein group does not live as long, what is not reported, is the high protein group took longer to develop cancer, but once they did, it was off to the races. And from THIS we are told “animal protein causes cancer.” No, the aflatoxin caused the cancer, the protein intake protected against the cancer for a period of time but then when the critters HAD cancer, the higher protein intake appears to have accelerated the disease.

My point: How much does ANY of this have to do with “normal” healthy individuals? And by normal/healthy I’m talking about the tiny (but growing) percentage of people eating something that looks like a paleo diet, sleep well, exercise reasonably. What exactly do we get from looking at our population at large? I’d say one thing: Confused. Would this apply to the Okinawans? Kitavans?

Some take-aways

1-Reduce systemic inflammation (y’all know how), sleep, play, get sunlight, maintain your insulin sensitivity. These factors all seem to bode well for avoiding most cancers.

2-Supplement wisely, if at all. I made some pretty heavy handed fish oil recommendations in my book. I made those with the idea we could curb inflammation in sick, overweight people. I’d say my (and many other people’s) assumptions about that was/were wrong. I’ve had to modify recommendations down to the 2-4g level and have generally pushed getting as much of ones nutrition as possible from whole foods.

3-Maintain some perspective. For me life is about mitigating risks…trying to find the best ROI I can on happiness, meaningful work, etc. I’m pretty sure eating something akin to a paleo diet, smart exercise, community, lots of love are our best hedges against the unknowns of things like cancer. Is it a 100% “get out of Jail Free Card?” No, nothing is a guarantee, but there are better and worse bets.

Categories: Anti inflammatory diet


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  1. Andy says

    Could you direct me to where I can read up on high doses of omega-3 not helping curb inflammation in the sick and obese? I thought that was interesting and was trying to find some specifics on google but to no avail.

    • says

      I’m not sure exactly where to go for this but the big picture: lipids turn over in th e cell membranes at a limited rate. More does not speed this up. Excess pufas are highly reactive, peridiabetics have elevated systemic inflammation…so it all conspires to make a nasty situation.

  2. says

    Hey Robb,
    Your fish oil recommendation in your post was 2 to 4 grams. Is that the EPA plus DHA?

    My supplement says “fish oil concentrate” 4000mg and right below that it says EPA 1600mg DHA 800mg. This has always confused me to tell you the truth.

    Have Fun, Train Hard,


  3. Monte says

    Good stuff Rob! Between you and Mark Sisson it’s nice to have two Guru’s to go to for a balanced response to this stuff. My wife just wants me to quit saying “Rob Wolf says.”

  4. says

    Yeah, I’ve always felt iffy about taking a ton of supplements every day. I think it’s better to just eat healthy food that has all you need inside of it.

  5. says

    Any fule kno that high intakes of omega 3 are immunosupressive. So you get the anti-inflammatory effect, which might reduce cancer triggers, but IF a cancer forms, you don’t have the same defense against it.
    However this may be specific to prostate cancer which seems to be unusually fat-sensitive for some reason.

  6. says


    In point number 3 you say: “It would appear no correlation with prostate cancer and saturated fats was found (sorry vegans). The headlines seem equally able to say “saturated fat does NOT increase prostate cancer risk.”

    I can’t seem to find any reference in the paper regarding saturated fat. Could you please point to page in the article that suggests that point.

    Many thanks.

  7. says

    Have you also noticed how one of the serious scientists involved in warning us about nutrients essential to human functioning and health is on record, and the internet endorsing yoga for food portion control in the treatment of obesity. I really want to see how they set that one up. Was it a double-blind, randomised, cross-over etc test, or was it based on contemplative reflection and accurate measurements of prana? Another astounding success for scidunce!

    Are all the eskimos dead yet?

  8. says

    Well it’s good that there are people like you around to address this ‘bad science’. I don’t know how people conduct these ‘studies’, to me it’s just morally corrupt.

  9. Chirs says

    Thanks for the feedback Rob. Honestly, it is so hard to really determine what are the appropriate supplements (and amount) to sustain or improve a healthy body. Every time the science seems to confirm a fact, it only gets disputed or proven differently.

    Maybe in the end, it really is about eating whole foods…..since reading your book, I have been trying to do this, but was relying on supplements to help the process. Now, I am really wondering if it’s just money down the drain?

  10. says

    When I showed this article to my husband, he suddenly looked so confused. He told me that last month, he read about omega-3 and learned that it’s really good for the health. Now, it can cause prostate cancer.

  11. says

    Thanks for the insightful post, Rob. I appreciated the take-away “supplement wisely, if at all”. We have a tendency to supplement too much, too often. Just taking a pill doesn’t get us outside in the sun moving around and lifting heavy things.
    Also, great scene from The Simpsons:-). Thanks!

  12. BobB says

    Very interesting but what’s with all the miss-placed possessive apostrophes that litter the article?

    It’s N-3s, N-6s and TFAs, not N-3’s N-6’s & TFA’s.

    • says

      What’s with missing that I’d not have it proofread and sas trying to get it up quickly vs perfectly? 100 paleo demerits for poor reading comprehension.

  13. John Matwey says

    Thanks for commenting on the article. I had increased my intake of Omega 3 Fish Oil to 5g per day for the past month based on the recommendation in your book. Should I be reducing this? I’m all the way back down to my high school wrestling weight of 158, down from 180 after 60 days. I’d like to maintain this weight and keep my strength.

    • Rich Shuey says

      I think the best way to deal with the amount of omega 3’s that you should be taking is to get a red blood cell test (as apposed to the serum blood test that they used in this study.) and find out what your ratio’s are between omega 3’s and omega 6’s. Since you are likely eating a paleo diet you might not be needing high doses of fish oil, possibly only 1-2 grams is enough to keep you in the sweet zone of between 1:1 to 1:4 between your ratios.

      I think problems really begin to happen when we think of using a fish oil as a drug rather than as a food. Take it to fine tune your eating efforts to achieve a balanced body chemistry rather than as a weight loss or as a healthful antiinflammatory drug. When we think of it as a drug then we start thinking,” If I take more I am going to get more weight loss, less pain, than if I take less.”

      To me, the important thing is to give your body what it needs and anything more is simply going to unbalance you in the other direction.

  14. says

    Point number five definitely needs to be addressed as it is definitely a huge player in the inconsistency of omega-3 studies. Was this fish oil already oxidized?

  15. Kit says

    Someone on Abel James’ podcast said, “It is not about consuming more omega 3, but reducing Omega 6”. Perhaps there is something in that. I think so. There is no (little) money in ‘taking away’ though: as opposed to supplementing.

  16. says

    I have been taking Omega-3 for almost 2 years (fish oil cap). My doctor recommended it to me for Cardio Vascular health. I did not know it has effect on treating cancer as well. Thanks for awesome information. Laura

  17. JuanitaFrapp says

    Thanks for the perceptive post, Rob honestly I appreciate to take away supplements every day. I prefer a healthy diet and physical activity. Last month I have read article about Omega 3 but after seeing your reading your post i am confused omega3 It can cause cancer oh my god. That’s why I won’t take pills if doctor recommended I go through it.

  18. CytheriaUrs says

    These 7 points are really very informative; most of the people may not have any awareness until and unless reading this post. In fact for myself don’t know about fish oils about cancer.
    Thanks for sharing such valid information and please keep sharing your knowledge.

  19. daisayrose says

    The points which are mentioned here are really worthy and help for reducing the cancer. Fats are one of the best cleansing detox foods. Fats help to absorb toxins and flush them out of the colon. Omega – 3 fatty acids are used for the best cleansing detox. These fats are not only the natural cleansing detox; they also help to prevent constipation. Omega- 3 fatty acids find in fish, nuts and seeds. These acids may protect from cancer and reduce inflammation in the body. Omega3 also restrict the tumor cells growth which may cause cancer. Rather than going for capsules if we eat fish, nuts and seeds we can get omega3 fatty acids.

  20. says

    As a naturopathic urologist who primarily deals with prostate cancer – I find this study to be highly flawed with most better designed studies showing the protective aspects of fish oils. If people stop taking fish based on this study they are doing a major disservice to themselves.

  21. Aakriti Ghai says

    Omega 3 fatty acids are usually said to be good for health. but i have studied it is good for some organs and bad for some of the other. as per a recent study fish oil which is a rich source of omega3, does not strengthen brain that has been believed for centuries. yes it raises the chances of prostate cancer but helps in treating the breast cancer.see the link
    Fish Oil Does not Help Maintain Brain Power

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