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Old 07-11-2013, 10:38 PM   #1
Luke Conner
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Study claims fish oil supplements raise risk of cancer 70%

http://www.dailymail.co.uk/health/ar...cancer-70.html (WFS)

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Fish-oil supplements credited with a range of health benefits could trigger prostate cancer.

Experts found that omega-3 fatty acids may raise the risk of the most lethal form of the disease by more than 70 per cent.

Researchers warned against omega-3 pills, and recommended eating just one or two meals of oily fish per week.

Fish-oil supplements are said to protect against heart attacks and strokes, stave off arthritis, boost brain power and prevent behaviour disorders in children.
However, scientists found that those with the highest levels of omega-3 in their blood were 71 per cent more likely to develop fast-growing, hard-to-treat prostate tumours.

They were also more likely to contract the slower, less deadly form of the disease, with the overall prostate cancer risk raised by 43 per cent.

The team from the Fred Hutchinson Cancer Research Centre in Seattle warned: ‘There is really no evidence that taking dietary supplements is beneficial to health, and there is increasing evidence that taking high doses is harmful.’

Dr Alan Kristal said the levels of omega-3 linked to the increased cancer risk would be reached by taking just one supplement a day, or three or four meals of fish such as salmon and mackerel each week.

Of mealtimes, he said: ‘There are good things in fish, so the message is moderation. It is probably not bad for you, and it tastes good.’

Taking omega-3 was also associated with a 44 per cent greater chance of developing low-grade prostate cancer

Taking omega-3 was also associated with a 44 per cent greater chance of developing low-grade prostate cancer

However, he stressed that when compared to fatty acids received by eating oily fish, the amount consumed via pills was ‘huge’.

It is unclear how fish oil could trigger tumours, but omega-3 may restrict the immune system, or damage our DNA. It is also unclear if it helps tumours to grow and spread.

The finding came amid a wider research project of more than 2,000 men, examining whether supplements of vitamin E and the mineral selenium can help prevent prostate cancer – the most common cancer in British men, killing more than 10,000. Selenium provided no benefit, and vitamin E increased the odds of contracting the disease.

Dr Kristal said: ‘As we do more and more of these studies – and I have been involved in them most of my career – we find high doses of supplements have no effect or increase the risk of the disease you are trying to prevent.

‘There is not really a single example of where taking a supplement lowers chronic disease risk.’

Professor Malcolm Mason, of Cancer Research UK, said: ‘The results of this study are surprising, and we clearly need more research to understand what is behind them.’

Although he stressed the researchers could not be certain whether the study’s participants ate oily fish or took omega-3 supplements, he said the results ‘show how complex the effects of food supplements might be’.

Dr Iain Frame of Prostate Cancer UK agreed that ‘larger and more complex studies will need to take place before we understand how the risks of a diet high in omega-3 balance against [its] benefits’.

Several recent studies have called omega-3’s benefits to the heart into question, too. One, which examined 20 studies involving almost 70,000 people, found that those who took omega-3 were no less likely to die of a heart attack or stroke than others
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Old 07-12-2013, 05:51 AM   #2
Todd R Bailey
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Re: Study claims fish oil supplements raise risk of cancer 70%

http://examine.com/blog/fish-oil-and-your-prostate/ (WFS)

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Stating "fish oil causes cancer" due to this study would be a mistake, as it is a case-cohort study (conducted at one time point only), and a temporal relationship is not made. While unlikely, with the data available, it could also be possible to state "prostate cancer causes a higher n3 concentration in the blood."

The temporal aspect is important, since fish oil supplementation can drastically change serum levels of omega-3s in the blood. It is quite common for people diagnosed with prostate cancer to supplement with fish oil, as it is commonly touted to be cancer-protective (which would mean that prostate cancer precedes fish oil supplementation). A previous study using persons from SELECT using a design that could assess this temporal relationship found no relation (either protective or harmful) with prostate cancer incidence.

Furthermore, this study did not measure mortality. When looking at mortality, fish oil seems to be associated with reduced mortality. In simpler words, it was found to not help prevent prostate cancer, but reduced your chances of dying from it.

Also of interest is the large ranges observed (as in, the 71% value had an actual range of somewhere between 0% and 192% with a 5% margin of error), which either suggests other factors are at play influencing the results or large differences in how ones body responds to omega-3 ingestion.

At the most, we can state that prostate cancer is associated with higher omega-3 ratios in your blood. This study poses a chicken-egg problem - which causes which?

This study and no other studies in existence can currently be used to say that fish oil causes prostate cancer. If anything, this study begets a plethora of questions in regards to the relationship between prostate cancer and omega-3 but proves nothing."
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Old 07-12-2013, 06:03 AM   #3
Eric Trent Miller
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Re: Study claims fish oil supplements raise risk of cancer 70%

I haven't logged in to this forum for months, but I am on like 3grams a day of fish oil. Logged back in specifically to post this, and saw Todd did already.

wtf?

http://www.fhcrc.org/en/news/release...te-cancer.html link is work / fam safe
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Old 07-12-2013, 06:37 AM   #4
Phil Washlow
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Re: Study claims fish oil supplements raise risk of cancer 70%

This is the problem with people/the media. They take correlation data (often small correlations) and develop causitive headlines that scare people.
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Old 07-12-2013, 07:43 AM   #5
Eric Trent Miller
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Re: Study claims fish oil supplements raise risk of cancer 70%

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Originally Posted by Phil Washlow View Post
This is the problem with people/the media. They take correlation data (often small correlations) and develop causitive headlines that scare people.
agreed. glad Todd posted an educated counterpoint.
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Old 07-12-2013, 08:29 AM   #6
Matthew Swartz
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Re: Study claims fish oil supplements raise risk of cancer 70%

I saw this yesterday and decided to read an article for once. To sum it up: "We think omega 3 increases your risk of prostate cancer by 70%! We're not sure how or why or if that's even true, but we're gonna say it anyways!"

They didn't even distinguish between supplemental omega 3 and real fish consumption in the 70% (IV) group! They also just lumped every omega 3 supplement together. Most generic omega 3 supplements are full of filler crap. Who says it's not that? Total junk research.
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Old 07-12-2013, 10:47 AM   #7
Alexander Granick
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Re: Study claims fish oil supplements raise risk of cancer 70%

Correlation does not imply causation. Someone get a hold of this paper. I want to read it.
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Old 07-12-2013, 11:09 AM   #8
Jordan Higgins
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Re: Study claims fish oil supplements raise risk of cancer 70%

Read this then decide
http://examine.com/blog/fish-oil-and-your-prostate/
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Old 07-12-2013, 11:13 AM   #9
Alexander Granick
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Re: Study claims fish oil supplements raise risk of cancer 70%

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Originally Posted by Jordan Higgins View Post
As a scientist I prefer to read things for myself first.
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Old 07-12-2013, 12:34 PM   #10
Darryl Shaw
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Re: Study claims fish oil supplements raise risk of cancer 70%

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Originally Posted by Alexander Granick View Post
Correlation does not imply causation. Someone get a hold of this paper. I want to read it.
Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial.
Brasky et al. doi: 10.1093/jnci/djt174


Edited to add bonus meta-analysis.

The relevance of serum levels of long chain omega-3 polyunsaturated fatty acids and prostate cancer risk: A meta-analysis.
Chua et al. Can Urol Assoc J. 2013 May-Jun; 7(5-6): E333E343.


*All links wfs*

Last edited by Darryl Shaw : 07-12-2013 at 01:02 PM.
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