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The Fish vs. Fish Oil Smackdown


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Update: I now recommend Extra Virgin Cod Liver Oil from Rosita as my preferred cod liver oil product. For more information, read this article. You can purchase EVCLO here.

So far in this series we’ve looked at why fish is superior to plant-based sources of omega-3. We’ve examined the importance of reducing consumption of omega-6 fats. We’ve considered how much omega-3 is needed to support health and treat disease. And we’ve revealed that concerns about the safety of fish consumption have been overblown, and that eating fish regularly is not only safe, but incredibly beneficial.

In this article we’re going to compare fish with fish oil as a means of meeting our omega-3 needs, and for overall health and wellness. The comparison will be based on the following criteria: nutrient content, potency, absorption, cost and environmental impact.

Fish oil has become wildly popular in the last few years, as people increasingly understand the importance of omega-3 in the diet. However, part of the reason for fish oil’s popularity is related to concerns about the safety of eating whole fish – concerns that we now know are unfounded.

With this in mind, let’s see whether whole fish or fish oil are the best choice for most people.

Nutrient content

Fish: contain not only EPA and DHA, but also vitamin D, selenium, protein, co-factors and a more complete fatty acid profile than fish oil. Selenium, in particular, is important because it protects against mercury toxicity. Vitamin D protects against nearly every modern disease plaguing us today. A 6 oz. portion of wild salmon contains 1,700 IU of D, which is difficult to obtain in that amount from other dietary sources.

Fish oil: most oils contain only EPA and DHA, although salmon and cod liver oil also contain moderate amounts of vitamin D. Fish oil has a more limited fatty acid profile than whole fish, and doesn’t contain selenium.

Potency (levels of EPA & DHA)

Fish: a 6 oz. portion of wild salmon contains 883 mg of EPA and 1,111 mg of DHA. 2-3 servings a week of salmon, combined with a low intake on omega-6, would be adequate for most people.

Fish oil: this is where fish oil may have an advantage over fish.

Because it is molecularly distilled and purified, fish oil can have high concentrations of DHA and EPA. 6 capsules of Jarrow Max DHA would provide 1.5g/day of DHA, a level that would be difficult to obtain from eating fish.

You’d have to eat approximately 8.5 ounces of wild salmon every day to obtain that much DHA.


Here’s where things get a bit tricky. I talked about potency above, and mentioned the levels of EPA and DHA in both fish and fish oil. However, those levels mean very little unless we consider how well they’re absorbed.

Several studies indicate that fish oil supplementation is not as effective as epidemiological evidence on the benefits of fish consumption suggest it would be. It appears that the presence of other fats in the fish activates processes required to absorb the EPA and DHA properly. This explains why the EPA and DHA are better absorbed from eating whole fish than from taking fish oil.

In one study comparing the effects of fish and fish oil, researchers found that levels of DHA after 6 weeks of salmon consumption were nine times higher than after fish oil administration.

The authors hypothesized that the configuration of fatty acids in whole fish is familiar to our body and thus easier to absorb. Conversely, the fish oil alone doesn’t adequately activate the process of fat absorption required to assimilate the fatty acids.

Another study confirmed this by demonstrating that fish oil is absorbed much better in the presence of a high-fat meal. They found that the content of n-3 fatty acids in the body tissues rose dramatically when the fish oil was taken along with 12g of olive oil.

We can draw two conclusions from these studies:

  1. EPA, and especially DHA, is much better absorbed from fish than fish oil. The effect may be as great as nine-fold. This means that we would need nine times less DHA from fish to obtain the same amount of DHA from fish oil. Put another way, we’d need nine times more DHA from fish oil to obtain the same amount of DHA from fish. So, using the 6 oz. portion of salmon as an example, with 1.1g of DHA, we would need to take 9.9g of DHA from fish oil – roughly 36 capsules/day of the Jarrow Max DHA – to obtain the same amount of DHA we’d get from the salmon. That’s a lot of fish oil!
  2. On the other hand, taking fish oil capsules with a high-fat meal can greatly improve their absorption, to the point where they may be on par with whole fish. (I say “may be” because the scientific literature is mixed on this.) This is likely due to the effect described above, where the presence of other fats activates the body’s fat absorption mechanisms.

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This is also tricky to compare, since prices and availability of fish vary regionally. A straight comparison of the cost of DHA obtained from fish and fish oil also ignores other important factors, which we’ve already discussed above, such as the presence of other nutrients and the differences in absorption.

Let’s assume for the sake of comparison that fish oil is taken with a high-fat meal to improve absorption and that absorption rates of EPA and DHA are roughly similar between the two. Let’s assume that wild salmon is available for $13/lb. (I know it is much less in some areas, and much more in others).

Let’s assume also that we’re shooting for a daily intake of 500 mg of DHA.

To obtain this amount of DHA from salmon, you’d have to eat just over one pound per week (19 ounces). That would cost you $15.45.

To obtain this amount of DHA from Jarrow Max DHA, you’d have to take 2 capsules per day. Assuming you bought a bottle of 180 capsules from Vitacost for $14.70, you’d pay just $1.14 for the same amount of DHA.

However, you’d have to consider the following caveats:

  1. It’s uncertain whether, even with a high fat meal, you’d be absorbing the same amount of DHA from the fish oil as you would from the salmon
  2. The salmon has large amounts of protein, selenium, vitamin D and other fatty-acids and co-factors that the Jarrow fish oil doesn’t have
  3. Other oily fish that are significantly cheaper than salmon, such as sardines and mackerel, are also very high in EPA and DHA.

Environmental impact

Overfishing and fish farming have already seriously damaged the health of marine ecosystems, and threaten to do even more damage if fish and fish oil consumption increases.

Much has been written about this elsewhere. Charles Clover’s The End of the Line: How Overfishing is Changing the World and What We Eat provides a particularly astute (and scary) analysis of the impacts of current methods of fishing on global ecosystems.

In short, I believe the most responsible choice we can make is to limit the fish we eat to those certified by groups like the Marine Stewardship Council (MSC).

However, even those groups are not infallible. Recently concerns have been raised over MSC’s decision to certify a salmon fishery in British Columbia where the salmon population is declining rapidly. Environmentalists and scientists have protested the decision, but the MSC seems to have moved ahead regardless.

Unfortunately it’s not a cut and dry issue, and those who are interested in eating fish harvested in a sustainable matter will have to do their own research and stay abreast of changing policies and practices.

In general, though, most environmentalists and scientists support the MSC certification. MSC has a list of fish they consider safe to eat on their website, which you can refer to.

MSC also has a certification label (pictured below) they provide to vendors of MSC-certified fish that you can look for when you’re shopping.

The sustainability of fish oil production is even more difficult to gauge. Some oils are produced as a byproduct of fish harvesting, and manufacturers claim that they are simply making use of something that would normally be discarded. While this is certainly better than harvesting fish solely for their oil, it still supports harmful fishing practices.

The safest bet is to only use fish oil that is made from fish that are certified by MSF or a similar organization, such as the Environmental Defense Fund. Vital Choice Wild Salmon Oil is one example, as is Jarrow Max DHA (which is made from anchovies and sardines, both of which are generally regarded as safe to eat from an environmental standpoint).

The verdict

The question of whether fish or fish oil is a better choice is complex and depends upon several different factors. These include whether DHA is needed for maintenance or therapeutic effect, access to sustainability caught wild fish, financial considerations, and the presence of other nutrients in fish.

For those who are generally healthy and want to stay that way, I think reducing omega-6 consumption and eating a moderate amount of oily fish (2-3 6 oz. portions per week) is the best choice. This will get you plenty of EPA & DHA along with high quality protein, selenium and vitamin D. If wild salmon is out of your price range, mackerel and sardines are both high in EPA and DHA and certified by the MSC as safe to eat.

For those who have a chronic, inflammatory condition such as cardiovascular disease or an autoimmune disorder, I would recommend a combination of whole fish (perhaps the same 2-3 6 oz. portions per week) along with a high quality fish oil. This ensures that you are getting the benefits of whole fish along with the added therapeutic effect of higher doses of DHA and EPA. Somewhere around 1.5g per day of DHA would be a good therapeutic dose, which would mean taking 1g/day of DHA in fish oil capsules in addition to the three 6 oz. portions of oily fish.

In the next and final article of this series, I’ll discuss the criteria for choosing a fish oil and make recommendations based on those criteria and clinical experience.

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Join the conversation

  1. Hi Chris,

    I’m currently following an autoimmune protocol. I’m not eating eggs, nuts, and night shade veggies. Also, due to candida issues I’ve also cut out fruit, fermented foods, and starchy veggies. Pretty much all I eat is vegetables (cauliflower, broccoli, cabbage etc) and fish (wild salmon 1 or 2 a week), free range chicken and grass fed beef. Also lots of avocados, bone broth (3 c a day) and coconut oil.
    Here are my questions:
    1. If I’m avoiding fermented foods, would fclo be okay? Also, since I’m not doing any dairy at all, even butter, right now since my digestion is weak.. would the fclo with butter oil be okay?
    2. Since I’m avoiding fermented foods, would I be able to eat raw unpasteurized sauerkraut?
    Thank you!

  2. Excess vitamin A is only problematic in the presence of vitamin D deficiency. Studies have shown that attaining normal D levels through supplementation raises the toxicity threshold of A to 200,000 IU a day. That’s an incredibly high amount that you won’t get from taking FCLO.

    • chris, thanks for this article and clarification on vit A and D, as well as the fermented cod liver oil. since you recommend not taking a multi, have you written an article on what supplements you do recommend in general?

  3. Chris,
    I have been taking fermented cod liver oil for about a month now. I recently started jucing vegtables, mostly ones high in vit. A. I am concerened about getting too much vit A now. What is your opinion about that? Thanks

  4. Nick: yes. I’m not a huge fan of multi’s, because I think it’s better to selectively supplement with whole-food sources of nutrients we know we need. You’ll be getting A, D, K2 & E in the fermented cod liver oil, so you won’t need those in a multi.

  5. Hi Chris,

    I am new to cod liver oil. I just ordered the cod oil you recomended. My question is with the high content of A and D in the cod oil, should I discontinue my multi. vit which already contains those nutrients? I dont want to take too much. Thanks

  6. Yes, there’s always some oxidation that occurs with heat. But it’s not that we have to avoid it completely. We just need to minimize it, and make sure we have enough anti-oxidant rich foods in the diet to mitigate the potential damage. Fish is very high in selenium, which is a potent anti-oxidant, so although there will be some oxidated PUFA in fish there are also antioxidants.

    • How can you talk about oxidated PUFA in one post and claim fermented clo is ok in another?
      In the studies you referenced on absorption of fish oil over fish – were these studies using triglycerides, ethyl, or rancid fermented clo? Based on the form you’ll have different outcomes. Fermented clo would have the lowest effect on balancing your HUFA, ethyl esters wouldn’t perform much better, while the triglyceride form outperforms by minimally 50%. The Jarrow MaxDHA you reference is an Ethyl Ester fat.
      Just sayin.

  7. Hi Chris,

    Thanks for these amazing articles — it’s so hard to find unbiased information on anything health related.

    I was wondering if you could dispel this seeming paradox that I see after reading this series. You say that oxidized fatty acids are bad. But unless you’re eating raw fish, aren’t you oxidizing (via heat) all those beneficial fatty acids in the fish when you cook them?

    I’m guessing there’s a simple answer to this but I can’t figure it out.

  8. Along the same vein as JBG’s comment, I’m curious to know your opinion on cans and packs of salmon and tuna.  My husband and I eat this several times a week for convenient lunches.

    • Canned salmon is particularly beneficial. Canned tuna is fine, as it doesn’t have more mercury than selenium. I prefer the line-caught, wild tuna and salmon.

  9. Most (all?) canned salmon is wild-caught Alaska salmon.  It is way cheaper than fresh.  Locally (Illinois) it is available at Aldis for $2/14.75 oz can.  Grocery-store canned salmon has nearly a half-gram of sodium per 1/4-can serving, but no-salt-added salmon can be bought (for two-three times as much $$) on the internet.
    Ie, canned salmon is about half the price of sardines, is very tasty, and comes from a well-manged fishery.  It’s a way almost anyone can afford to eat fish.

  10. Great post and excellent blog from what I’ve read so far Chris.
    Just wanted to add that the whole ‘dosage by consensus’ or from ‘anecdotal experience’ with regard to fish oil in new trainees has problems.  We have to remember that most of these people coming from a sedentary, SAD-eating lifestyle into a healthier diet and smart training (which they can definitely get from people like Poliquin, Wolf, and others) are going to see rapid improvements and likely lots of weight loss and reduction in inflammation from their new changes.  It is tempting to attribute this success to the supplements they take while doing this.  But it may be true that they see improvement in SPITE of taking high dose fish oil, not BECAUSE of it.  There are so many confounding factors that can contribute to their good results that it seems impossible to attribute the success to fish oil or any other supp.
    Until we see a solid body of well-designed, peer-reviewed randomized clinical trials looking at high fish oil dosage and some health markers, I prefer to remain skeptical and err on the side of caution- keeping supplement dosages low-to-moderate (no more than 3g of high quality EPA/DHA per day) and emphasizing food sources for these important oils along with elimination of excess N-6 intake.

    • I couldn’t agree more, Preston. I’ve written elsewhere that I think giving 20g/d of fish oil is downright dangerous. The increase in oxidative stress could easily outweigh any potential anti-inflammatory benefits – especially because oxidative stress itself causes inflammation.

      Your point about confounding factors is spot on. A lot of people I know use this type of reasoning to support a vegan or vegetarian diet. They say how much better they felt going from the SAD to the vegan diet. Conclusion: vegan diet is healthy. Um, no. The majority of the improvement there is much more likely to come from what was removed (stopping the SAD) then what was added (tofu, brown rice, veggies).

      • Im right there with you guys! Ive been using carlsons liquid fishoil but thinking why do we need all these supplements? Look around and notice the corruption and $$ maker these products have become! What if we did what our ancestors did and just seek out best quality food? Absorption for digestive health is key or else its wasted. As I begin my coaching/counseling practice im going to help share the “truth” about food/supplements and eliminating the toxic, inflammatory ingredients is job #1.

  11. Christian,
    You’re very welcome.  I’m using this short period of time in between graduation and the licensing exam to get as much research and work done on my blog as I can. Once I get my license and start private practice, I’ll have a lot less time to put into this.

  12. Hi Chris,
    Just wanted to thank you for the feedback on my question.
    Also the fish oil guide is excellent, as is the recent post about why we should eat fish.
    It’s hard to keep up with you! You are so incredibly productive.

  13. Hi Christian,

    I like Robb’s podcast and he seems like a pretty knowledgeable guy.  However, I do have a problem with his recommendation of 1g of EPA/DHA per 10 pounds of body weight, for a couple of reasons.

    First, as you know, n-3 LCFA is highly unsaturated.  Any FAs that are highly unsaturated are susceptible to oxidative damage – regardless of whether they are n-6 or n-3.  Consuming 20g/d of fish oil could lead to a potentially dramatic increase in oxidative damage.  Our ancestors likely never ate more than 3-4% of calories as PUFA, and drinking 20g/d of fish oil is going to exceed that ratio by a mile.

    I understand that he’s not suggesting such a high intake over the long-term, and I get that the point is to push out the n-6 in the tissues and replace it with n-3.  It is true that it can take up to 6 months to shift the fatty acid profile in tissue.  However, I think significantly reducing n-6 intake and moderately increasing n-3 intake (to a maximum of 1.5 – 2g/d) is a more balanced approach that will decrease inflammation but also protect against oxidative damage.

    The other problem I have with that recommendation is that, as far as I’ve heard, Rob never tells people they need to be careful about what fish oil they choose, nor does he tell them how to choose it.  I’m writing an article all about that now that will be published in a couple of days.  Not all fish oils are created alike, and many of them are oxidized and/or made with poor quality ingredients.

    I’m concerned that people hear Robb’s advice and just go down to the store and buy the cheapest fish oil they can find (which I can certainly understand, if they’re going to be taking 20g/d of the stuff!)  Then they’re consuming huge amounts of rancid, oxidized fats and possibly significant amounts of PCBs, dioxins and heavy metals without realizing it.

    Poliquin has a good point and I don’t see a problem with using fish oil in that way, but I don’t see why 1.5-2g of a high quality, highly bioavailable product isn’t enough to produce the desired effect.

    What I’ve seen in several studies is that there’s a diminishing return at doses above 3g/d.  In other words, more is not necessarily better – especially considering the potential for oxidative damage.

    I’m keeping an open mind about this but these are my thoughts.

  14. Hi Chris,

    That’s another excellent article! Especially the discussion about absorption was an eye opener.

    This is about some additional aspects that I’ve been thinking about:

    Some practitioners (e.g., Poliquin and Robb Wolf) recommend a very high intake (such as 0.5 – 1g /EPA, DHA per 10 pounds of body-weight/day) initially in a person transitioning from SAD to an ancestral diet.

    As far as I understand things (I may have got it wrong here and I don’t want to put words in other peoples’ mouths) the rationale has to do with counteracting the inflammatory effects of “legacy” omega 6 present throughout the body, especially if the person is losing weight. (There is also a spectrum of issues related to the metabolic syndrome that fish oil remedies.)

    The practice doesn’t seem to have a large basis in formal scientific studies, but is rather an idea that has been derived from successful clinical applications. People in the transitional stages are generally reported to do very well on higher amounts of fish oil and without any negative side effects. (Though I suspect that in some people high doses aren’t that well tolerated because of gut issues.)

    Poliquin has also mentioned fish oil supplementation as a therapeutic tool that helps kick start a person’s gradual behavioral change into better eating patterns. Fish oil, as it is providing essential brain nutrients, rapidly impacts patients’ mood in a positive manner and thus makes it psychologically easier for them to move forward with further changes in a positive direction. (This vs. immediately prescribing an over-night changes in diet).

    Perhaps you have any comments on these aspects of fish oil supplementation.

  15. Thank you so much for your informative articles! with all the confusion out there you are doing an exellent job to get to the heart of the matter and sort it all out for us.

    I would like to know your opinion on fish roe, is it better than fish? If yes  witch particular fish roe are the best? Thanks in advance.    

    • Wild salmon roe is probably the #1 choice for obtaining DHA. Unfortunately, it’s incredibly expensive. To get a therapeutic dose of DHA, it would cost something like $27/day.

      • Hi Chris!

        I feed my 14mo old daughter spoonfuls of whitefish caviar and salmon caviar, and smoked wild salmon (lox) with her pasture raised scrambled eggs at breakfast to give her healthy sources of EPA/DHA, and she loves it. Should I be concerned at all about the sodium content in those products for my baby? I buy Echo Falls brand caviars and Changing Seas brand lox. Do you think they are providing good sources of EPA/DHA relative to the sodium?

  16. Hi Chris, excellent blog & articles.  I currentlyordered Green Pastures Fermented Cod Liver Oil.  Have you heard of this product? If so, what is your opinion the quality of this product?

    • Shameer,

      Thanks for your feedback! GP FCLO is #1 on my list of product recommendations. The next and final article in this series will be called “The Definitive Guide to Fish Oil”, so stay tuned!

  17. Vitamin A does compete somewhat with absorption of D, but vitamin A is also an important co-factor that stimulates the vitamin D receptor.  The study you referred to showed a correlation between higher amounts of A and decreased protection from D, but did not show causation.  It had several other flaws.  In situations like this, I believe it’s best to go with the evolutionary wisdom of our ancestors, who thrived on foods like organ meats that are naturally high in both A & D.

    I am still uncertain about krill oil myself, so I don’t know how much I have to add to the debate.  There are very few studies supporting its use, and the few studies that do were sponsored by the company that manufactures the krill oil.  I did find one independent study that suggests it is effective, and there are many positive anecdotal reports like yours.  So I’d say it’s probably just fine.  I just wish there were more studies.

  18. This is a good series for readers needing the latest information on Omega 3. One study I read shows cod liver oil isn’t recommended because vitamin A interferes with the absorption of the vitamin D.

    I hope your next post in the series mentions Krill oil. Some nutrionists consider it superior to other fish oil. I can use Krill oil but other fish oil supplements give me nausea, even taken after a meal.

    I’m not fond of fish, so I try to eat it once a week and also take the Krill oil daily.

  19. I agree that fiber should probably be avoided with fish oil.  I don’t recommend fiber supplementation in general.

    It makes perfect sense that liquids are absorbed better than capsules.  One less step for the body to go through to assimilate the oil.  But many people won’t take liquid fish oil.

    The last post in the series will cover how to choose a fish oil, including the toxins issue.

    Thanks for your comment!

  20. Great article as per usual!
    I would also add that any fat soluble supplement (fish oils, vitamin e, etc) should not be taken with fiber.   A wild speculation, but perhaps one possible reason for the lower absorption in the supplement takers, is that they were also supplementing with fiber.
    Also, there is a least one study suggesting that supplementing via capsule form, is not as effective as supplementing via liquid:
    Finally, wouldn’t the presumed lack of mercury /pcb in the distilled supplements be another consideration when choosing?  I recommend brands that has been independently certified by IFOS for purity:

    • I thoroughly enjoyed this article because it confirms fears that pills, to get DHA and EPA, have non-concrete scientific efficacy.

      • Also, I am concerned about vitamin E toxicity to my liver, since medical journals say pills, use vitamin E as a preservative for the Omega fats. Let me tell you just find a nice recipe calling for affordable canned sardines (noteably in spring water, not vegetable oil due to too many calories), but, DON’T DRAIN your canned fish since you will be POURING YOUR OMEGA – 3’s DOWN THE DRAIN.

        Personally I find mayonnaise and sardines mixed up and spiced up with hot peppers and broiled with cheddar cheese on rye toast is quickly satisfying and requires little clean up.