Fish, Not Fish Oil Capsules

Yesterday I recommended eating about a pound a week of salmon or sardines as part of the strategy for achieving an optimal omega-6 to omega-3 ratio.

Yet this is not the way many health-conscious people obtain omega-3 fatty acids.  They buy fish oil capsules. 

The trouble with this approach is that omega-3 fats are chemically fragile:  their carbon double bonds are easily oxidized.  EPA has 5 double bonds and DHA 6 double bonds, so they are the most vulnerable of all dietary fats.  They easily become rancid.

Fish oil capsules often sit on a shelf for months before they are eaten.  If someone offered you the opportunity to eat salmon that had been sitting on a shelf for six months, would you do it?  No? Then why accept the same deal with salmon oil?

In fact, clinical trials have compared eating fish to eating fish oil capsules.  Fish consumption has an excellent record in a number of clinical trials, but fish oil capsule supplements do not. 

In the Diet and Angina Randomized Trial (DART-2), 3114 men with stable angina were followed for 3-9 years. There was a control group, a group advised to eat oily fish like salmon, and a group taking 3 fish oil capsules daily.  There was a significant increase in sudden cardiac death among the subgroup taking fish oil capsules. [1]

So, give up the fish oil capsules:  they’re all too likely to poison you.  Instead, buy some fresh fish.  Poached or baked salmon is an excellent summer dinner.

[1] Burr ML et al. Lack of benefit of dietary advice to men with angina: results of a controlled trial. Eur J Clin Nutr. 2003 Feb;57(2):193-200.

Leave a comment ?


  1. Unless you are talking about eating sushi.. wouldn’t cooking the fish also break those delicate omega-3s?

    Also, aren’t the VAST majority of studies involving omega-3s, done using supplements? Perhaps not as beneficial as compared to eating raw fish, but “poison”, really?

  2. Hi snoop,

    Cooking can damage fats, that is why we recommend cooking fragile foods at low temperatures. We tend to bake salmon at 300 – 325 F.

    There have been a large number of studies, some using supplements, some fish, some “advice” which is usually to eat fish.

    Evaluating these studies is complex, because omega-3s that have not gone rancid are health-improving for almost everyone on modern diets. Supplements provide a mix of non-rancid and rancid fish oil, so a mix of benefits and toxicity. Depending on how fresh they are, they could produce benefits or harm.

    The nice thing about the Burr et al study is that it compared fish to fish oil supplements head-to-head in a realistic setting.

    I think it confirms what we should expect from basic chemistry and biology. Chemically fragile oils in capsules are likely to go rancid after months on a shelf, and are not likely to be as healthy as the oils in a freshly-killed fish.

    “Poison” here just has its technical meaning: a toxin that you ingest as food.

    Best, Paul

    • Yes Paul, but wouldn’t the exact same problem arise from sardines, which are presumably from a can? Don’t cans – like pill bottles – sit for months on a shelf before being eaten? Salmon also, is frequently canned.

      Should I be unconvinced that the bottle of fish oil from Carlson’s in my fridge is rancid? It tastes great… I’d love to know if this ‘rancidity’ could be smelled/tasted.

      • If fish have gone rancid, you can tell. If the contents of a fish oil capsule are rancid, you can’t tell. The bottled fish oil is also better than the capsules.

        • I’ll take that to mean that at this time, bottled fish oil – assuming it tastes good (not rancid) – we hope to be every bit as nourishing omega3-wise as eating fish?

        • Hi Paul

          what about antioxidants such as Vit E and rosemary extract, that are often capsuled with the fish oil? would they prevent its oxidation?

          • Hi Gianluca,

            In case Paul doesn’t respond, I would suggest:

            The oil requires certain extraction, which may damage it even before the antioxidants are added.

            Also keep in mind that vitamin E from supplements is likely to be harmful compared to natural vitamin E, see the discussion in the book.

  3. Just to support your post: VBR Hans

  4. Paul — what about fish oil from a bottle?

  5. Hi John,

    Better than capsules, but I still favor fish.

  6. first, great book. diet is one of my pet interests and your book tops my list.

    i’ve been taking fish oil from bottles for a few months now. i’m with you about getting omega 3’s from fish and natural sources but i don’t feel like my fish oil is rancid. it doesn’t taste rancid. i have had bottles that clearly were rancid and noticed this immediately because of taste.

    how would tablets get oxidized? they are sealed. they certainly could be destroyed during processing, but shouldn’t they be stable for some time sealed in capsules?


  7. Hi Chris,

    I’ve used bottled fish oil in the past as well, but we don’t need huge quantities of it … I think real fish is the best source.

    It’s not possible to make capsules that won’t let molecules of air inside. That’s why capsules usually contain vitamin E or other antioxidants.

    There are various papers in Pubmed talking about oxidation of omega-3s in capsules. See e.g.,, just for a start.

  8. I rely on canned sardines with bones and skin intact for my omega-3s. The brand is King Oscar and when I contacted the company, I was told the sardines are heated to 291 to 300 degrees maximum. I buy them in water and also packed in extra virgin olive oil. I often eat a can a day to offset the huge amounts of nuts I’ve been eating (All tree nuts are a huge vice for me and I am endeavoring to cut them out completely again. Once fall/winter hit – I just crave them and can eat 8 oz or more in a sitting of hazelnuts, almonds, macs or mixed nuts with no digestive distress at all. All the omega 6 must be awful but I’m hoping the high fiber offsets this. That is also why I eat sardines almost daily. I am slender and when I cut out nuts entirely, I can drop to slightly underweight. I am 5’3″ tall and with nuts I weigh about 105 — after dropping them entirely, I can drift to under 100 pounds which is far too thin for me especially as I approach menopause. I have no trouble at all staying low carb paleoish — no problem dropping grains and dairy — but this nut vice is awful. Your book mentions that it can take 5 or 6 years to wash out the omega 6s from cells — I’m thinking that given my nut addiction — it might take decades! PS: I am really enjoying your book — keep up the great work.

  9. Thanks, Annie. It’s an interesting problem, gaining weight; not much of a literature on it. I found that when I became well nourished my weight went up by 15 pounds, and my body composition (posture, chest size relative to waist size) improved. So you might try our supplement regimen and “micronutritious foods,” perhaps those will help you add muscle and bone density.

    Best, Paul

  10. Since this comment is quite late, maybe it won’t help anyone, but I’ll try, anyway.

    I used to take fish oil from a bottle. It turns out that, even though I do not have any swallowing problems and took the fish oil immediately before a meal, a tiny bit of the oil worked its way into my windpipe every day, and after many years, it caused what is known as “lipoid pneumonia”.

    That’s a rare condition, and I think it is basically benign, but it turned up as a shadow on an X-ray taken for a different problem. The doctors investigated, and on the CAT scan and PET scan, it looked exactly like lung cancer. It required a surgical biopsy before they found out that it was not cancer but this lipoid pneumonia. All that expense for tests and the expense and bother (and danger) of surgery, just from taking fish oil!

    So, taking liquid fish oil has this potential problem, as well as the others that Paul mentions.

  11. Hi Keith,

    Thanks for letting us know, I had never heard of that. Fascinating! Might have some bearing on lipid-induced inflammation elsewhere.

  12. Hi Paul,

    Two questions,

    Why do you think the people who were advised to eat oily fish also saw an increase in cardiac death?

    Should I avoid canned goods like sardines/kippers because of BPA?

  13. Hi James,

    Well, there wasn’t significant increase in cardiac death in those eating fish.

    Here’s a relevant passage from the paper:

    The apparently adverse effect of fish advice was confined to the second phase of the trial (data not shown), when a much higher proportion of subjects were given fish oil capsules than in the first phase. During this part of the study, some of the subjects allocated to fish advice were subrandomized to receive fish oil capsules, so a survival analysis was carried out to examine the effect on those subrandomized to capsules rather than to dietary advice. Table 8 shows that the hazard ratios for each mortality category were higher in the fish oil than in the dietary fish group, and significantly different from unity only in the former group. The dietary fish group comprises all subjects allocated to fish advice throughout the trial, including those who chose to take capsules instead of fish, but excluding the subrandomized fish oil group.

    In other words, they had data for a mixed group that ate fish and took capsules, and from another group that only took capsules. Excess deaths were twice as high in the capsule-only group as in the mixed group, and statistically significant in the capsule-only group but not in the mixed group.

    It’s possible that there were no excess deaths in fish-only eaters, although they had no data from fish only eaters.

    Other studies have tended to find benefits from eating fish, so I think fish eating is probably beneficial. Fish oil capsules are harmful.

    I think it’s better to get fresh or frozen fish than fish canned with BPA. But I’m not sure how dangerous the BPA is.

    Best, Paul

  14. I don’t like eating fish so I am stuck taking fish oil capsules for omega 3. However, I use a top of the line brand from New Zealand, Xtend-Life. The process they use is very advanced with guaranteed freshness and purity. I take the version that has added lycopene and astaxanthin. Do you think this is a reasonable choice or should I drop the fish oil regardless? Thanks!

    ps. Do you still sell your book in PDF format for us Kindle users?

  15. Hi Rick,

    It’s OK. The other choice is to buy the liquid fish oil and keep it refrigerated.

  16. Paul,

    I know Annie mentioned a specific brand of canned sardines but do you have any misgivings about canned sardines or mackerel (in either water or olive oil) in general or can we pretty much rely on them to meet our omega 3 needs for those of us that don’t have access to fresh fish?



  17. If you are worried about the BPA in the cans, you can order those fish in BPA free cans from Vital Choice www,

  18. My whole family takes fermented cod liver oil. It’s only made by one company in the world, a family company here in the USA. They ferment it in the traditional, Scandinavian way. They started making their own after touring the cod liver oil plants in Norway and being disappointed in how they processed and denatured the oils.

    I seem to think that fermenting the oil protects it from rancidity. It’s also not in a capsule but forms a gel-like consistency.

  19. Why You Should be Eating Fish | - pingback on September 10, 2012 at 7:00 pm
  20. Any thoughts about possible chemical pollutants or radiation in ocean fish?

    • Hi Holly,

      The ocean dilutes poisons rapidly, so those would only be a problem in specific places and times, eg near Fukushima after the nuclear disaster and before the radioactive elements have had sufficient time to decay.

      Chemical pollutants are a major problem in shallow water farming of fresh fish, or saltwater fish in shallow estuaries, in places where there is a lot of pollution, eg southeast Asia or China. Fish like catfish or tilapia are most vulnerable.

  21. WHY YOU SHOULD EAT FISH... | leicestercrossfit - pingback on May 11, 2013 at 8:53 am
  22. I really enjoy salmon, and could eat it every day. My question is, can you eat too much? Thanks.

  23. what is the consensus given all the studies done?

    Also what is the recommendation for people eating largely organic and grass fed? Do we need that much omega 3 anyway?

  24. Fish Oil is so 2010 - pingback on August 29, 2013 at 10:51 pm
  25. Hey Paul,

    I was turned off about fish oil after hearing your comments, but then I heard this from Dr. Mercola (whom I also seek advice from)

    Any thoughts on Krill Oil compared to fish oil? I know fish is the best but I don’t want to eat everyday because of mercury posioning.


  26. Hi Paul-

    Are there any concerns about eating a tin of sardines everyday?


    • Hi Kate,

      If a tin is 4-5 ounces then that would be about double the dose of omega-3s we recommend. Not a big deal there. Hopefully the BPA or metal doses are small, and the fish well preserved. I think it’s OK if that’s what you like.

  27. Thanks so much! I’m happy to hear someone else gets it!

    I was tried the fermented cod liver oil. But the whole thing didn’t make sense to me. I don’t understand if people are against polyunsaturated oils why is
    fermented cod liver oil ok?

    Polyunsaturated oils are VERY unstable, oxidizing quickly when
    exposed to oxygen, light and heat—even just sitting in a bottle, but
    also when they go into our bodies—and turning rancid. (including
    omegas) Also Fermented foods require a glucose source to create
    (metabolize) a by-product e.g. lactic acid that prevents the food from
    decomposing. The result is a pleasant sour taste that one would find
    with sauerkraut, pickles, yogurt, etc. Cod liver oil has no glucose
    and cod livers have very little glucose (mostly protein, fat, water
    and some minerals). The livers and the oil simply go from fresh to
    rancid in a short period of time. If left to continue decomposing the
    oil will become putrid leaving a foul smell and taste.

    Furthermore, Cod, like Shark, are long-lived fish. As they go about
    living for years and years, and during that time, they accumulate
    environmental toxins. And the toxins are most concentrated in the livers. So when you drink Cod liver oil, you should expect environmental toxins!

    Sadly, atlantic Cod is an over-fished and threatened species.Thanks for shedding light on this subject. best, Javier

  28. a recent study (published Dec 2014) that looked at the quality and content of fish oil capsules sold in New Zealand (just fish oils in capsules, did not look at krill, calamari, or algae oils);

    We evaluated the quality and content of fish oil supplements in New Zealand. All encapsulated fish oil supplements marketed in New Zealand were eligible for inclusion.
    Fatty acid content was measured by gas chromatography. Peroxide values (PV) and anisidine values (AV) were measured, and total oxidation values (Totox) calculated.
    Only 3 of 32 fish oil supplements contained quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that were equal or higher than labelled content, with most products tested (69%) containing <67%.
    The vast majority of supplements exceeded recommended levels of oxidation markers.
    83% products exceeded the recommended PV levels, 25% exceeded AV thresholds, and 50% exceeded recommended Totox levels.
    Only 8% met the international recommendations, not exceeding any of these indices.
    Almost all fish oil supplements available in the New Zealand market contain concentrations of EPA and DHA considerably lower than claimed by labels.
    Importantly, the majority of supplements tested exceeded the recommended indices of oxidative markers.
    Surprisingly, best-before date, cost, country of origin, and exclusivity were all poor markers of supplement quality.

  29. Is Saturated Fat Good or Bad For You? | Webmarks Online - pingback on January 31, 2016 at 11:40 am
  30. Amazing book and website. I was just wondering if canned salmon was suitable or does the fat denature due to warm temperatures.

  31. Would canned fish have the same problem with oxidation as fish oil supplements? It is heated at very high temps and stored at room temperature for long periods of time just like capsules. Did any studies specify whether fish was fresh/frozen or canned?

  32. I also am trying to find out if canned salmon is a good choice. It’s so easy to open a can and put it, including the bones and skin, on a salad. We just don’t often cook fresh samon in my house. Does anyone have feedback on whether the canning process can damage the PUFA in salmon?

  33. Hi Paul, I love seafood but am a little cautious now regarding my omega 3 intake. I know from reading your book that eating salmon one meal a week is ok as is eating shellfish one meal a week too. Would I be advised against eating any other shellfish on top of these two meals per week? I enjoy shrimp too but worry eating these during the week as well as salmon and mussels may be risky and push me over the safe omega 3 limit? Thanks for any advice, much appreciated.

  34. Hi Paul

    I see above that sardines are recommended, but is that still recommended? Recent research by the University of Exeter in the United Kingdom and the University of Queensland in Australia has found sardines now have high levels of microplastics? How does this potentially effect our health?

    Many thanks for your opinions.

  35. Fish Oil is so 2010 - Critical MAS - pingback on February 25, 2024 at 11:28 am

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