Yes. I think getting rid of all DHA is a mistake. It seems to be a U-shaped curve for this one. However, EPA seems the more the better. So I’ll be increasing my EPA intake and decreasing but not eliminating DHA.
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Just pointing out that they jury may still be out re above
There could be overadjustment bias in those last studies
And given that the current study not only adjusted for education, but ALSO for 4-5 or so other variables that are correlated to income adding income to this study could lead to overadjustment bias here.
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100 mg/day of DHA is probably enough. But you get more than that with just one portion of salmon per week. So no need to supplement.
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Which ones?
I don’t know about overadjustment. In any case the lack of adjustment for income isn’t the worst to me. The worst is the healthy user bias and the lack of presentation of results stratified by fish oil use. What if you don’t have any significant trends anymore when you look at fish oil users only or non fish oil users only? How come they didn’t present that data?
Matt Kaerberlein’s answer:
I don’t really disagree with your position, although I don’t find the evidence against DHA to be all that convincing. Having said that, I haven’t closely read all the latest literature in this space, mostly because of time constraints and also because I get frustrated at how poorly many of these studies are designed and/or analyzed.
One of the biggest limitations to most studies in this area that I’ve seen is that they don’t actually measure omega-3’s either before or after supplementation. It’s tough to draw any conclusions - other than that population level supplementation probably doesn’t have big effects either way - in the absence of actually measuring biomarkers to see where folks started and where they ended up. If you know of good studies that did this, let me know.
Obviously, the relationship between omega-index or specific omega-3’s and health outcomes is extremely complicated and impacted by genetics and other environmental (diet, exercise, etc.) factors, likely as well as whether the source comes from diet versus supplements. Even brand of supplement may matter…
I do agree the evidence for benefit from supplementation tilts toward EPA for many outcomes, at least for now. The one I take is 3:1 EPA:DHA.
Honestly, like most supplements, I think the real answer is that supplementation is unlikely to move the needle much for most people. Especially if you are eating a crappy diet and don’t get other lifestyle factors dialed in. How much does it help if you do practice an otherwise healthy lifestyle? Hard to say, but for now it makes sense to me to get your omega-index up near the range is that most correlated with better health outcomes across populations.
I feel like he didn’t really read my email 
(at least he’s honest: “Having said that, I haven’t closely read all the latest literature in this space”), but he seems to directionally agree (he takes 75% EPA).
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Actually, checking this, many studies looked at the baseline levels and it seems that, unfortunately, supplementation is worse in people with low baseline levels!
People with low omega 3 levels were worse off with supplementation!
This was also noted by @Neo regarding another study: “The best responders were those with higher (aggregate) initial levels” Omega 3 makes me depressed: why? - #80 by Neo
So it’s even worse than I thought…
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It looks like there’s a big sex based difference? There seems little effect on men? Confidence intervals for women is completely within the favoring placebo, strong effect; for men, of course straddling neutral. The thing that’s interesting here is that if you eat fish, skip fish oil supplements.
However, it is also important to note: this is in regards to depression, depressive symptoms, mood disturbances. OK, but not everyone experiences such effects from EPA/DHA. On a population level, prevalence is relevant. And what does that mean? Does it affect brain health only in those who experience such symptoms from supplementing and those who don’t experience symptoms are unaffected?
I don’t supplement with DHA, but do modestly EPA (3x week, 500mg EPA). So I don’t know if I would get depressed if I took DHA. But if EPA supplementation also causes this effect, at least in those with low baseline levels, then it becomes a question of dosage - at what dose is this noticeable. FWIW, I don’t have any depressive symptoms or mood disturbances, and never had them. My modest EPA supplementation hasn’t changed that over the span of 2 years, which is how long I’ve supplemented. But I’m also male, so…
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Yes, gender effect. Women absorb omega 3 more so I guess that beneficial and detrimental effects, if any, are more obvious in women: Study: omega-3 uptake higher in women; we must account for gender in research, GOED VP says
Based on other studies (MR + RCT + animal models), DHA is the cause. Not EPA.
For what it’s worth I’m a male with above average EPA and DHA levels and I get depression from (EPA + DHA) but not from EPA-only (even at 2 g/day).
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Looking at this chart again, the most impressive thing is that there’s not a single subgroup that benefits from 1 g/day omega 3 (EPA + DHA) over 5 years. Even at this relatively low dose, supplementation was either detrimental or absolutely useless when it came to depressive symptoms.
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Dr. Greger gives his 2 cents:
Should You Take Fish Oil
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He doesn’t mention the brain at all. It would be interesting to hear his thoughts on why he left that out, since it’s a big reason why so many people take fish oil.
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Here’s my talk with Bill Harris, PhD of OmegaQuant about Omega 3’s. He might be biased (he sells the omega index test) and he might not know about every single omega 3 study ever completed but the guy has 40 years of scientific study in the field and 300+ published research papers. I’m inclined to trust his opinion.
Bill says:
- an omega index of 8+% is ideal, and higher omega index (EPA + DHA in red blood cell membrane) associated with lower ACM, lower mortality from CVD, cancer, and everything aside from CVD and cancer, on average). ALA does not seem to matter so it is not included in the test.
- get 1.5 grams of combined EPA and DHA (fish and supplements combined) everyday (or on a daily average taking a couple times a week); the ratio of EPA:DHA doesn’t matter as far as anyone knows
- you don’t need an expensive fish oil; the oxidation risk is a marketing ploy in his opinion
- no reliable evidence that DHA is harmful; no evidence DHA is good for the brain or better than EPA
- some omega 6’s are good for health (as good as EPA/DHA), so an omega 3:6 ratio is meaningless without knowing which omega 6’s. Just get enough EPA/DHA
- Afib risk is questionable and tiny in any case
- fatty15 is completely unproven
- SPMs are not necessary to supplement (the body makes SPMs from EPA and DHA) and the currently available SPM supplements are not SPMs but rather substrate.
And here is my own Omega Index (full version). I recommend everyone get tested and then use the calculator on the OmegaQuant website to determine EPA / DHA need to reach 8%.
Omega-3 Index 2025.pdf (3.7 MB)
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Bill the grifter strikes again!
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Fine to be skeptical, but lets not be cynical. Be specific in criticisms please.
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Are you joking? I’ve spent hours researching the evidence and posting it everywhere on the forum. Especially here:
- Vitamin O (Omega 3) for athletes - #4 by adssx
- How much omega-3 do you need? - #62 by adssx
- How much omega-3 do you need? - #70 by adssx
Not a single person has denied the evidence other than gesturing “But we’ve been doing it for a long time based on association studies!”. Matt Kaeberlein “doesn’t really disagree with my position”: How much omega-3 do you need? - #69 by adssx Bill/OmegaQuant never got back to me.
The evidence on omega 3, EPA and DHA is the opposite of every single thing that Bill said (based on the list of bullet points).
His arguments are mostly based on weak association studies that he published.
He sells and promotes the omega 3 index.
He is the definition of a grifter.
Prove me wrong.
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Yikes. Hard to trust someone who describes RCTs and MRs as not reliable.
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The data you’ve provided is very helpful.
I haven’t listened to the podcast, and have not followed the EPA DHA thread that closely - which is likely the situation with most people. So rather than just calling someone a grifter, its helpful to explain why a person is wrong.
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Yes, you’re right, but in this case, my posts proving it wrong start just three messages above. Anyway, I wonder if there would be a way to put a bounty on that. I would be willing to pay someone who could prove me wrong on DHA being detrimental to health. It’s very unfortunate (and quite telling) that none of the “influencers” (beside Matt K) got back to me…
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Don’t you find it concerning that practically every single health guru supplement stack features EPA/DHA, even though they may differ widely on most other supplements? There is as far as I can see near universal consensus that fishoil/long chain marine omega 3 FA must be a feature of everyone’s daily supplement. Even vegan gurus advocate algae based oils.
And yet, if you really dig deep, there seems surprisingly weak evidence in support of that. There is actually more evidence for fish consumption.
So if they all agree on such weak evidence, of what worth are the rest of their recommendations, where they even disagree among themselves.
I guess it’s the very banal truism that science or argument does not gain validation from “authority” - very shameful to have to say this. We know this from the age of 10 years old.
Deming: “In God we trust. All others must bring data.”
Where is the data?
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I agree, it’s very weird. I assume that:
- No one does the research.
- It seems “natural” / “low risk”
- As you say there’s evidence for fish consumption so people infer from that that omega 3 supplementation is good (whereas fish consumption might be good due to avoidance of red meat and other benefits than just omega 3)
- It gets more complex because omega 3 is made of different components. I’m sure that if EPA and DHA were totally different supplements never sold together as part of something else then people would just get EPA. Imagine if tomorrow you cannot buy vitamins separately but you can only buy “Vitamins” containing everything. Then all health gurus would tell you to take “Vitamins”. They would be somehow right: most people need some kind of vitamins…
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