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Chris Kresser on Fish Oil

Member Forum >> Coronary Disease & Cholesterol Protocol >> Chris Kresser on Fish Oil

Bob Niland

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Posted: 3/17/2017 3:12:24 PM
Edited: 3/17/2017 5:36:26 PM (2)
Chris Kresser on Fish Oil

Chris Kresser is apparently going to keep at this, so here's another look at his 2015 fish oil critique, as revised by him on 2017-01-24:
Should You Really Be Taking Fish Oil?.

I remarked on the original 2015 article when a reader asked about it on the WB Blog. The cite numbers have since changed, as reflected below (and now linked, which I couldn't do on the blog, due to link count limits).

Chris Kresser's 2017 version of the article embeds this tweet-bait:
   Is it possible that fish oil is beneficial for one person
   and harmful for another? #fishoil

to which I would reply : absolutely.
If someone stays on a standard diet, or remains on a statin, uses a sub-clinical dose of ω3, or uses an inferior product, they might well expect no benefit. An otherwise therapeutic dose might even be harmful in some of those scenarios, particularly if they also follow some of the crazy protocols in the reported trials (margarine, seriously?).

Reference #1 is a meta, which concludes “Dietary supplementation with omega-3 fatty acids should be considered in the secondary prevention of cardiovascular events.” Bottom line: study does not conflict with Cureality/Wheat Belly (C/WB) recommendations.

Reference #2 was a “placebo controlled” trial of B-vitamins and ω3, but used only 600 mg of DHA+EPA daily. Statin use was not accounted for. There was apparently no control of diet. The placebo was not disclosed, and it's often a confounder, as the majority of nutritional researchers are either clueless about what is really inert, or don't know the difference between “placebo” and “control”. Bottom line: at 18% of WB recommendation, dose is too low to provide insight.

Reference #3 was another placebo controlled trial, in a post-MI population “…receiving state-of-the-art antihypertensive, antithrombotic, and lipid-modifying therapy…”, with even less DHA+EPA (376 mg), delivered in 18 grams of PUFA (margarine)! The paper itself admitted that this was “low dose”. Bottom line: dose too low, statins in use, and no chance of driving ω6:3 ratio to below 2.

References #4, 5 and 6 were focused on afib. I didn't look at those because C/WB makes no claims about fish oil and afib.

Reference #7 was a meta, relying on trials using doses ranging from 400 to 4,800 mg day. There was no focus on subject diets. Placebos were all over the place, or poorly defined, often adverse fats (a negative confounder). I didn't re-dig for statin confounding. Papers (only 14, and the list appears to include the “negatives” above) were selected strictly by keyword search of databases. The keyword list was rather narrow. “Our meta-analysis showed insufficient evidence…”, but they had to ignore (exclude) one trial even to say that. Also, “Among the trials, there was no significant difference in the occurrence of adverse events, such as gastrointestinal troubles or gastrointestinal bleeding, between the intervention and placebo groups.”, which is what happens on otherwise adverse [consensus] diets. Bottom line: iffy analysis of iffy original research.

Reference #8 (another meta) is pay-walled. Bottom line: no way to know, but the abstract itself was non-inferior: “Overall, omega-3 PUFA supplementation was not associated with a lower risk of all-cause mortality, cardiac death, sudden death, myocardial infarction, or stroke based on relative and absolute measures of association.”.

Reference #9 (another meta) - can't even find full-text. Bottom line: no way to know.

Reference #10 is new for the article (a 2016 paper) and another meta. I didn't drill down all the cites, because they were all 2013 or earlier, and likely covered by the other meta mastications here. This meta concluded inconclusively with another non-inferiority: “There is currently a lack of evidence to support the routine use of omega-3 PUFAs in the primary and secondary prevention of CVD.”

Reference #11 (another meta) concludes “our results supply evidence that long-term effect of high dose omega-3 fatty acid supplementation may be beneficial for the onset of cardiac death, sudden death and myocardial infarction among patients with a history of cardiovascular disease.” Bottom line: study does not conflict with C/WB recommendations.

Reference #12 was a controlled trial that had odd intervention groups. The fish oil amounted to 3 grams daily, but the FO-only group got no other dietary advice. The other groups got pretty bizarre dietary advice. One chart shows that the fish-only advice group had better survival, but these clueless researchers decided it was better to conclude “This result is unexplained…”. Bottom line: seems to support C/WB recommendation despite inept design.

Reference #13 was a clinical trial of FO on people with metabolic syndrome. The full text is available, but is in Portuguese. The abstract (English) captures the essence of it “We conclude that intake of fish oil resulted in decreased levels of triglycerides and increased the TRAP (total antioxidant capacity) of patients with MS (metsyn); however, increased LDL levels and insulin resistance, were observed.” Bottom line: the FO improved a metric that matters (TG), but violated LDL-C dogma, and they were pretty clueless about when apparent IR is really a problem.

Reference #14: “The present study provides evidence that increased dietary ω-3 polyunsaturated fatty acids and extra virgin olive oil have beneficial synergistic effects on lipid metabolism and oxidative stress in patients with MetS.”, so does not contradict C/WB.

Reference #15 is pay-walled, so I can only see the abstract. It was really a trial of soy, and sailed into the trial with a bias against fish oil. No other dietary intervention was done, and I can't draw any real conclusions from the abstract. Bottom line: no way to know.

Reference #16 was a test of krill oil, which C/WB discourages. Bottom line: no insight on C/WB fish oil.

Reference #17 used only 900 mg of DHA+EPA and was “restricted to patients with impaired fasting glucose, impaired glucose tolerance, or diabetes”, plus a bunch of CVD diagnoses. Half the subjects were on statins. There was no apparent other dietary intervention. Bottom line: dose too low to be insightful on C/WB recommendation, plus statin confounding (admitted by the article).

References #18-23 were in respect to cancer. Chris himself concludes “research on omega-3 and fish oil supplementation on cancer is decidedly mixed.” Based on what I found by following the earlier ones, I didn't bother to look. Omega 3 doesn't strike me at the moment as being a huge factor one way or the other in cancer. The things to focus on in cancer may be: very low carb, grain free, low inflammatory, immune system support (microbiome) and generally avoid mitochondrial antagonists.

References #24-27 were all about oxidation levels in actual ω3 products. These papers have a point: namely that all ω3 trials need to specify quality/potency of the ω3. None of these oxy-caution papers specified brands, alas. ConsumerLab does have oxidation as one of the quality criteria they focus on when testing ω3 supplements.

Getting your FO from actual fish is a great idea, as long as you have some assurance that the fish is fresh (or fresh-frozen), is wild-caught (not farmed, nor sea-farmed), and is non-GMO. A CAFO fish is going to be low in ω3 and high in ω6.

Bob Niland [disclosures] [topics]