2

votes

Omega 3 fish oil & prostate cancer.

Answered on September 12, 2014
Created July 11, 2013 at 2:36 PM

This has been all over the U.K news today, i don't take the stuff myself but i'm sure a lot of people do, i'm wondering is it down to the quality of the oils? i.e fermented or not. http://www.dailymail.co.uk/health/article-2359466/Taking-omega-3-fish-oil-supplements-increase-risk-aggressive-prostate-cancer-70.html

Medium avatar

(10611)

on July 12, 2013
at 03:06 PM

If the media doesn't have any spectacular distractions they switch to reporting on navel fuzz. Anything to sell papers.

C4deaa6bb01626b4569e8992890381ab

(925)

on July 12, 2013
at 02:37 PM

I agree, all the uk media is a joke. I don't read newspapers because of this reason. I heard this on the radio whilst driving..(can't escape it all eh) so I though I'd throw it in here for some real views. Personally I just eat oily fish.

C6648ab69e5a1560c7585fe3ba7108fb

(880)

on July 12, 2013
at 02:15 PM

Update: The MDA link that Mscott posted is extremely telling. The point about low-fat diets raising the level of serum O3 is HUGE and I'm surprised it's not being mentioned more.

C6648ab69e5a1560c7585fe3ba7108fb

(880)

on July 12, 2013
at 01:42 PM

still stands: get your O3 from food, not supplements, and eat a varied diet (i.e. 1:1 or 2:1 O6:O3 ratio, as they noted that linoleic acid levels reduced the risk) to reduce your risk of all diseases. Keep in mind that you should have an O3:O6 ratio; O6 fats aren't inherently bad, just in excess, and it's likely that O3 fats are the same way.

C6648ab69e5a1560c7585fe3ba7108fb

(880)

on July 12, 2013
at 01:40 PM

Excellent, thanks Tamandua. Looks like they did a good job isolating the serum O3 condition (though someone better versed in statistics than I should really explain the methods); as SUSTAINEDfitness noted above though, they didn't differ between supplements and real fish or participants' lifestyle choices aside from O3 intake. They also didn't control for the quality of O3 consumed by the subjects; it's possible that the subjects that were supplementing with O3 were using a low-grade, contaminated source that contributed to the prostate cancer. In the end, my original recommendation

C45d7e96acd83d3a6f58193dbc140e86

on July 11, 2013
at 09:49 PM

Couple of points, no control. It was just observational, and they didn't even distinguish between supplements and real fish. Chances are the people in the study ate crap and there were too many variables to take anything good out of it. For example, If I eat Standard American Diet, but just add lots of bacon, that will probably be bad for my health. If I eat lots of bacon in the midst of a clean paleo diet, it is healthy.

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 09:07 PM

Thanks for your input & links. Mscott

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on July 11, 2013
at 08:28 PM

Yea, I'm glad I'm not the only one who thought it was weird they found a decreased risk of prostate cancer with increased serum o6.

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 07:16 PM

Great answer paleot, thanks!

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 07:15 PM

I love oily fish, i don't supplement personally. Thanks for your input BGottfried

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 07:13 PM

I don't supplement myself as i love oily fish, i was just throwing it out there for anyone that does. I didn't hear them call it questionable on the radio RA, good point though. Thanks for your input.

De1095b2ba29c1035f00428cbfe3cc7c

(777)

on July 11, 2013
at 04:25 PM

they said on mainstream radio that the study was questionable, mainstream radio would usually be the first to jump on the latest fear mongering so it must be very questionable! just eat fish

D9e4b265ef308c8cabf847559fd8be2e

(370)

on July 11, 2013
at 03:12 PM

http://jnci.oxfordjournals.org/content/early/2013/07/09/jnci.djt174.abstract

32f5749fa6cf7adbeb0b0b031ba82b46

(41757)

on July 11, 2013
at 03:03 PM

Nutritionism... bleh. Damned if you do, damned if you don't. Too much omega-3, cancer. Too little, CVD.

  • C4deaa6bb01626b4569e8992890381ab

    asked by

    (925)
  • Views
    2.4K
  • Last Activity
    1254D AGO
Frontpage book

Get FREE instant access to our Paleo For Beginners Guide & 15 FREE Recipes!

6 Answers

5
A2c38be4c54c91a15071f82f14cac0b3

(12682)

on July 11, 2013
at 08:54 PM

I'm hesitant to believe these findings yet for two reasons: This is just one epidemiological study and a number of studies like it have either found omega-3 consumption is not associated with more prostate cancer or is associated with less prostate cancer (1, 2, 3) and experimental studies on mice have not shown fish oil consumption to be an apparent promoter of prostate cancer (4, 5, 6).

There's also a preliminary trial that suggests a low fat diet containing supplemental fish oil might be helpful in men undergoing treatment for prostate cancer (7).

Still, it may be that fish oils seem protective (or not harmful) against prostate cancer development in observational studies because a common source of fish oil, namely fatty fish, is rich in nutrients like selenium and vitamin D, which both show decent evidence that they can prevent prostate cancer (8, 9). In which case, it's possible fish oil could increase prostate cancer risk.

Both Denise Minger and Paul Jaminet have written a bit about this study and the possible effects of fish oil on cancer risk:

http://www.marksdailyapple.com/fish-oil-prostate-cancer/#axzz2YlrewGLp

http://perfecthealthdiet.com/2011/04/omega-3s-angiogenesis-and-cancer-part-ii/

I think the effect of fish oil on prostate cancer risk is not yet clear.

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 09:07 PM

Thanks for your input & links. Mscott

5
Cf08ad26759fdd206a2c9f9385080a57

(995)

on July 11, 2013
at 04:48 PM

I asked about this yesterday.. http://paleohacks.com/questions/202145/omega-3-supplement-prostate-heart-health. My take on it was that you can't take a SAD / western diet with a ton of omega 6, throw on a ton of omega 3 fat in concentrated form on top of it, and expect lower rates of cancer.

(Like from this study a few years back.)

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1890998/

Nevertheless, molecular mechanisms of omega-3 PUFA effects on prostate cancer remain elusive. Our data show that the high???omega-3 diet, with an omega-6/omega-3 ratio recommended by nutritionists, could effectively deliver omega-3 PUFA to the prostate (Supplemental Figure 2), delay tumor formation (Figure1) and progression (Figure2), and prolong survival ???(Figure 5) as compared with the high???omega-6 diet.

The absolute amount of PUFAs may also be of consequence, since high total fat intake has been associated with cancer incidence (24).

The 12-month survival rate for PtenP???/??? mice was 60% on the high???omega-3 diet, 10% on the low???omega-3 diet, and 0% on the high???omega-6 diet (Figure ???(Figure5).5). In fact, no PtenP???/??? mice on the high omega-6 diet survived beyond 10 months of age in our experimental group.

One of the largest prospective studies ( http://www.ncbi.nlm.nih.gov/pubmed/11403817 ), involving 6,272 men with 30 years of follow-up, indicated that fatty fish consumption was associated with decreased risk of prostate cancer (20). Serum levels of omega-3 PUFAs were reported to be significantly lower in patients with benign prostate hyperplasia and prostate cancer, and omega-6 PUFA levels were higher in patients with prostate cancer compared with age-matched controls (21).

(During 30 years of follow-up, men who ate no fish had a two-fold to three-fold higher frequency of prostate cancer than those who ate moderate or high amounts did.)

Clinically, prostate cancer is usually diagnosed in men age 60 or older, and cancer cells proliferate slowly. Therefore, dietary and/or chemoprevention are of particular importance for the management of prostate cancer. Our data imply a beneficial effect of omega-3 PUFAs on delaying the onset of human prostate cancer. It will be interesting to determine whether any beneficial effects can also be achieved by supplementing the diet with omega-3 PUFAs after tumor initiation has occurred.

It's also unclear where they got their oil (was it oxidized? TG-form? free of PCB's?) The article seems to suggest that omega-6 lowers prostrate cancer (which can't be true) -- "Higher linoleic acid (??-6) was associated with reduced risks of low-grade and total prostate cancer."

It seems they used ~800 people with cancer, then looked at how much Omega-3 they were eating. The guys who were diagnosed with cancer seemed to be putting more Omega-3 into their diet (maybe because they had cancer and were trying to get better..) Their control group was a randomly selected group, and those with cancer seemed to be trying to eat more omega-3. It doesn't seem to be a study where they take a bunch of healthy people and follow up on them much later. Kind of a flawed logic.

This study would be like if you took 800 people who get headaches and found that there was a high correlation between those with headaches and those taking advil/tylenol. Then you used a control group of 1,000 and asked who takes the most advil/tylenol and found they also had the most headaches. Then you say advil/tylenol cause headaches and it gets posted all over the news. The correct way to do this study would have been to take a few thousand people without headaches, feed them advil/tylenol for 30 years (while paying close attention to things in their diet that could negatively interact with the advil/tylenol treatment, like alcohol with tylenol or in the case of omega-3's, a SAD amount of omega-6's or contaminants), and see if they develop a significant amount of headaches as compared with control groups on varying diets (they probably wouldn't.)

Anyone have access to the full texts? http://jnci.oxfordjournals.org/content/early/2013/07/09/jnci.djt174.abstract

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 07:16 PM

Great answer paleot, thanks!

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on July 11, 2013
at 08:28 PM

Yea, I'm glad I'm not the only one who thought it was weird they found a decreased risk of prostate cancer with increased serum o6.

3
C6648ab69e5a1560c7585fe3ba7108fb

on July 11, 2013
at 02:53 PM

For whatever reason, I'm unable to find a link to the actual study (which seems odd honestly), so I can only comment on the various stories around it. I'd argue that it's too soon to tell for sure whether O3, fish oil, or something else is responsible for this, as all we know is that it was an obersavtional study (if someone can find a link to the study itself, we might be able to determine what the researchers did to isolate consumption of O3 in their findings to find this correlation). In the meantime, your best bet is to focus on getting your O3 from fish directly rather than fish oil; one of the articles I found mentioned that the difference between the low and high risk groups in terms of O3 serum levels was equivalent to roughly two servings of salmon a week. So eat some fish (but apparently not too much) each week and make sure your diet is varied :)

C4deaa6bb01626b4569e8992890381ab

(925)

on July 11, 2013
at 07:15 PM

I love oily fish, i don't supplement personally. Thanks for your input BGottfried

D9e4b265ef308c8cabf847559fd8be2e

(370)

on July 11, 2013
at 03:12 PM

http://jnci.oxfordjournals.org/content/early/2013/07/09/jnci.djt174.abstract

C6648ab69e5a1560c7585fe3ba7108fb

(880)

on July 12, 2013
at 01:40 PM

Excellent, thanks Tamandua. Looks like they did a good job isolating the serum O3 condition (though someone better versed in statistics than I should really explain the methods); as SUSTAINEDfitness noted above though, they didn't differ between supplements and real fish or participants' lifestyle choices aside from O3 intake. They also didn't control for the quality of O3 consumed by the subjects; it's possible that the subjects that were supplementing with O3 were using a low-grade, contaminated source that contributed to the prostate cancer. In the end, my original recommendation

C6648ab69e5a1560c7585fe3ba7108fb

(880)

on July 12, 2013
at 02:15 PM

Update: The MDA link that Mscott posted is extremely telling. The point about low-fat diets raising the level of serum O3 is HUGE and I'm surprised it's not being mentioned more.

C6648ab69e5a1560c7585fe3ba7108fb

(880)

on July 12, 2013
at 01:42 PM

still stands: get your O3 from food, not supplements, and eat a varied diet (i.e. 1:1 or 2:1 O6:O3 ratio, as they noted that linoleic acid levels reduced the risk) to reduce your risk of all diseases. Keep in mind that you should have an O3:O6 ratio; O6 fats aren't inherently bad, just in excess, and it's likely that O3 fats are the same way.

2
Ed71ab1c75c6a9bd217a599db0a3e117

(25477)

on July 11, 2013
at 11:04 PM

Just looking at the FA % tell you how bad this study is. Then when you realize that the population on this planet who has the best FA % is the Japanese and they have very low prostate CA and breast Ca you just realize the study is terrible flawed piece of reductive science. The TFA % in this study would not lower a HS CRP below three so no wonder they found higher prostate cancer risks. People have to really read the papers before they comment. Journalist and the media just respond to soundbites and 140 tweets to generate false beliefs to get a buzz.

Our observations matter a lot more clinically than this study.

1
D9cfa8953b89529a678f69169e0d5648

on July 12, 2013
at 01:23 PM

The Daily Mail is a joke, please stop taking it seriously. It is well known in the UK for pumping out endless spurious headlines -- usually about cancer, or immigration, famously "Immigrants give you Cancer!" -- that cater to a particular brand of middle-income anxiety. It's somewhere between National Enquirer and New York Post.

See here: http://www.thedailydust.co.uk/2009/02/19/20-strange-things-the-daily-mail-say-will-cause-cancer/

And here (for a humorous take): http://uncyclopedia.wikia.com/wiki/Daily_Mail

C4deaa6bb01626b4569e8992890381ab

(925)

on July 12, 2013
at 02:37 PM

I agree, all the uk media is a joke. I don't read newspapers because of this reason. I heard this on the radio whilst driving..(can't escape it all eh) so I though I'd throw it in here for some real views. Personally I just eat oily fish.

Medium avatar

(10611)

on July 12, 2013
at 03:06 PM

If the media doesn't have any spectacular distractions they switch to reporting on navel fuzz. Anything to sell papers.

1
4b01f55d55870d977668f4c10ac2290b

on July 11, 2013
at 09:03 PM

PCBs cause prostate cancer. Those impurities you find in CHEAP fish oil (and I believe cheap farmed fish):

http://www.foxriverwatch.com/prostate_cancer_pcbs_intro.html

And is it possible that because fish oil is very unstable that it becomes oxidized and causes these problems? Does simply cooking fish or grass fed beef cause them to become oxidized?

Sorry if I'm off I don't know enough about this stuff.

Answer Question


Get FREE instant access to our
Paleo For Beginners Guide & 15 FREE Recipes!