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
asked bysuperdad (925)
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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:
I think the effect of fish oil on prostate cancer risk is not yet clear.
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.)
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
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 :)
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.
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.
And here (for a humorous take): http://uncyclopedia.wikia.com/wiki/Daily_Mail
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):
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.