Thursday, 11 July 2013

How many working brain cells do researchers have? Part n+1

Once upon a time, I took the mickey out of some eejit researchers in How many working brain cells do researchers have? Guess what? I'm doing it again. A Facebook friend sent me a link to a worrying "new" study Omega-3 Supplements Linked To Prostate Cancer. Oh, dear. Things are looking bad for oily fish & fish oil supplements. Just a moment!

I did some digging on PubMed for the author and found this:- n-3 Fatty acids and prostate cancer risk. The main feature of wild oily fish & fish oil supplements is their high ratio of EPA & DHA (long-chain omega-3 fatty acids) to LA (a shorter-chain omega-6 fatty acid). It would therefore be logical to assess oily fish consumption and/or fish oil supplement intake by measuring the ratio of serum EPA:LA and/or DHA:LA and/or (EPA+DHA):LA.

What did Brasky TM, Crowe FL & Kristal AR actually do? According to the abstract, they measured only serum EPA, DHA & (EPA+DHA). They didn't measure serum LA. Therefore, if the subjects in the EPIC study ate a diet with a high omega-6 (n-6):omega-3 (n-3) ratio (i.e a Standard English Diet), subjects with a high serum n-3 level would have a very high serum n-6 level. As excessive levels of serum n-6 pufas are carcinogenic (see Completing the trine: Which are the safest fats?), it's not surprising that the study produced the results that it did.

There only one thing to do, in cases like this...
Because one palm just isn't enough!
EDIT: Here's a better analysis:- Fish Oil and your Prostate. It looks as though n-6 was measured, which makes my analysis wrong, but I'm keeping the double face-palm, as the full study is hidden behind a £30 pay-wall. Here's another good analysis:- Omega-3 Fats and Cancer.

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