RHR: Should Everyone Supplement with Fish Oil?

RHR: Should Everyone Supplement with Fish Oil?

by Chris Kresser

Published on

revolution health radio

Fish oil may not be all it was cracked up to be, especially in the case of heart disease prevention. In this podcast I'll discuss what the latest research says about fish oil supplementation.

Maybe two or three years ago most patients that came to me were taking some kind of fish oil supplement because the idea was we weren’t getting enough omega-3 in our diets, and there were studies that suggested that fish oil goes a long way toward preventing heart disease. But there have been some chinks in the armor this hypothesis over the past few years and especially so over the past year.

In this episode, we cover:

0:24  My two upcoming London seminars
6:43  The latest research on fish oil supplementation
10:47 Testing for omega-6 and omega-3

Links we discuss


Chris Kresser: Hey, everybody, it’s Chris Kresser from Revolution Health Radio.

My two upcoming London seminars

Today I’m going to answer a listener question, but before I do that, I want to remind you that my two events in London, October 31 and November 1, are coming up, probably only a few days away by the time you hear this.

The Saturday event is geared toward the general public and will cover a broad range of topics in the ancestral nutrition and health and functional medicine world. I like to do those events in a way that’s driven by the interests of people in the room. That one is nearly sold out, I believe, but I think there are still a few spaces. It’s going to be at King’s College, and a paleo lunch will be provided. It’s from 10 a.m. to 4 p.m.

And then the Sunday event is geared more toward clinicians and healthcare practitioners, though all are welcome to attend. I’m going to focus here more on trends that will define the future of medicine, functional medicine, and the crucial role of the exposome in health and disease. I’m going to present a systems model of functional medicine that I’ve developed to guide my own practice and also for my clinician training program. I’m going to talk about how to structure and layer a treatment for maximum efficacy, how to customize nutrition plans for individual needs, and of course, we’ll have a Q&A as well. That’s also from 10 a.m. to 4 p.m., will also include lunch, and is also at King’s College. There are still a few spaces left in that one as well, and this is going to be my first trip to the UK and probably my last trip, at least for a long while. I don’t have any plans to come back in the near future, so if you’re interested, I would love to meet you and see you at the events.

For the public event, you can find more information and register at ChrisKresser.com/UKpublic, and for the practitioner/clinician event, you can go to ChrisKresser.com/UKclinician.

OK, so now let’s dive into the show today. We have a question from Daniel from Sweden, so let’s give it a listen.

Question from Daniel: Hello, Chris. Daniel here from Sweden. In a local paleo forum, we have been discussing supplementation with omega-3 and if it’s needed or not, and there are quite a few people pushing a product from Zinzino, which is called Balance Oil or something like that. They have a test where they test out the ratio between omega-6 and omega-3, and I just wanted to hear your thoughts on it because it seems like their test almost always shows that the ratio is bad, which is in conflict with my own thoughts. I mean, if you eat a varied paleo diet and avoid excessive amounts of nuts and so on and you eat a lot of fatty fish, I think you should be able to have a good ratio without supplementing. It would be great to hear your thoughts on this and maybe get a better understanding if these tests are legit or if you think it’s just bad, bad testing. Thank you. Bye.

Chris Kresser: OK, so, yeah, this is a really good question, and I think a lot has changed in this area over the last even maybe three or four years, but certainly over the past 10 years. I think maybe 10 years ago, the vast majority of people would say, yes, everyone should be taking a fish oil supplement, and in fact, most patients that come to me, maybe not quite so much now, but maybe two or three years ago almost everyone that came to me was taking some kind of fish oil supplement because the idea was we weren’t getting enough omega-3 in our diets, and there were studies that suggested that fish oil goes a long way toward preventing heart disease, so this led to people taking sometimes quite high doses of fish oil capsules, maybe 3 to 5 grams a day or even more, and it became a really large industry and business with a lot of money at stake. But there have been some chinks in the armor this hypothesis over the past few years and especially so over the past year.

I actually recently published an article on this subject called “Should You Really Be Taking Fish Oil?” That was back in June. If you haven’t read that, I would definitely recommend googling it and reading it because I summarize a lot of the more recent evidence that suggests that fish oil may not be all it was cracked up to be, especially in the case of heart disease prevention.

The latest research on fish oil supplementation

Initial studies suggested that fish oil was beneficial for heart disease, particularly over the short term, and for people who had already had a heart attack—so this is secondary prevention, people with pre-existing heart disease—but several studies since then, including large studies and reviews of randomized clinical trials, have found that in adults even with pre-existing heart disease, long-term supplementation over three years with fish oil had no significant impact on cardiovascular endpoints. There were a few other trials that have looked at the effect of short-term fish oil supplementation on atrial fibrillation, and none of those trials—there were three of them—found that fish oil improved patient outcomes.

And then the meta-analysis of randomized clinical trials focusing on cardiovascular endpoints, like heart attack and stroke, found that fish oil did not reduce cardiovascular events or death and concluded that the evidence doesn’t support using fish oil supplements for secondary prevention of heart disease, meaning, again, people who have already had a heart attack. There is not much evidence to support that taking fish oil in that population will really do much of anything. And lest you think it was a problem with that meta-analysis, there were two other meta-analyses that were published right around the same time that came to similar conclusions.

Now, this isn’t to say that there isn’t any research that supports the use of fish oil for cardiovascular health. There was one meta-analysis in 2013 that found a protective effect on fish oil for preventing sudden death and heart attack, and certainly you can find studies that have had positive results, but I would say overall when you look at some very large recent studies and meta-analyses, the evidence supporting fish oil for preventing cardiovascular events is pretty weak.

What about metabolic syndrome? Because it’s obviously possible that fish oil could not be helpful for cardiovascular disease but could be helpful for metabolic problems. It’s another reason that it’s typically prescribed. If somebody, for example, has high triglycerides and low HDL, they might be given a higher dose of fish oil to deal with that. There is a recently published randomized clinical trial that looked at adults with metabolic syndrome, and they found that supplementation of 3 grams a day of fish oil along with 10 mL per day of olive oil for 90 days improved a lot of blood markers that are associated with metabolic syndrome. But it was interesting to note in that study that the fish-oil-plus-olive-oil group had better results than the group that took either fish oil alone or olive oil alone, and one reason for that may be that olive oil is rich in antioxidants and may have protected against the potentially greater risk of oxidative damage that comes from consuming a lot more polyunsaturated fat, which is what’s in the fish oil. So we might be seeing a scenario here where a higher dose of fish oil has some benefits, but because it’s polyunsaturated fat and has the potential to oxidize, there is also harm, and so we see no net change or in some cases even adverse effects when someone takes a high dose of fish oil, but when you add the olive oil, it has antioxidants and kind of cancels out some of that potentially harmful effect that the higher doses of fish oil have.

Testing for omega-6 and omega-3

But let’s bring this back a little bit more to Daniel’s question because he specifically asked about the ratio between omega-6 and omega-3 and some of the tests that are available to determine that ratio. I’ve seen a similar thing, too. I do a really advanced blood panel for patients that has, among other things, the omega-3 index as part of it, so it looks at the ratio of omega-6 fats and omega-3 in the blood, and it creates a scores. And I’m trying to remember if I’ve ever seen anyone that has had a normal score in the green. They rate the score in a kind of like traffic signal fashion with green being normal, yellow being intermediate or caution, and then red being really bad. Almost all of the values that I’ve seen have been in the yellow category, and this is probably a consequence of the fact that there’s so much omega-6 in our diet that it’s really, really difficult to get back to that historical ratio of omega-6 to omega-3, which was about 1:1 in some populations, maybe 2:1 in other populations. But in Western populations these days, the average is probably more like 9:1 or 10:1, and in some cases, on the Standard American Diet, if someone’s eating just tons of processed food with soybean oil—which can comprise up to 9 percent of total calories for some people—the ratio can be as high as 30:1.

Earlier on—and anyone who’s been following my work for a while will know this—I used to put a lot of emphasis on the omega-6-to-omega-3 ratio and it’s importance, but over the past couple of years, I’m changed my mind about that and gradually revised my views, and I’ve been writing about that and speaking about it, so this probably won’t be news to you, but it seems now that there’s less evidence really supporting the importance of the ratio and more evidence just supporting the overall intake of omega-3.

For example, if your intake of omega-3 is really low or nonexistent, you’re going to have problems. Of course, your ratio will be high because you’re almost certainly getting omega-6 from the diet. It’s much harder to avoid than omega-3 is. But if your intake of omega-6 is higher, especially if it comes from real, unprocessed food—which I’ll come back to in a second—let’s say you’re eating avocados and chicken skin and nuts and natural foods that are high in omega-6, but you’re also eating some preformed EPA and DHA from cold-water fatty fish and some other omega-3’s, plant-based omega-3’s from vegetables, walnuts and flaxseeds, etc., from my reading of the research and a lot of discussion with Chris Masterjohn, whose opinion I really respect on this issue—he’s done a ton of research on the polyunsaturated fats—and in my reading of the literature, there’s not a lot of evidence supporting the idea that that person who’s eating real-food-based omega-6 even in substantial amounts and omega-3’s is going to be at increased risk of disease. The omega-3 index was created with this whole ratio in mind, so even someone like that, who’s eating healthy omega-6’s and a fairly substantial amount of omega-3’s, will still probably score in the yellow category on that test, but I don’t really think that you can say that that person is going to be at significantly increased risk of disease.

Now, let’s consider another scenario where someone is eating, again, a Standard American Diet. They’re eating a lot of chips and fried foods, foods that have been fried in omega-6 polyunsaturated seed oils like corn oil, cottonseed oil or soybean oil, sunflower or safflower oil, and they’re eating out in restaurants all the time—unfortunately, restaurants tend to use those oils because they’re so cheap—and then their intake of omega-3 is really low, and they come back with a score of yellow on that test. That person’s going to be in a different position than the person who has a high or even medium-high intake of omega-6 from, like, avocados and nuts and chicken, and also has a pretty substantial intake of omega-3, but the ratio is still putting them in the yellow versus somebody who has a low intake of omega-3 and a pretty high intake of omega-6, all from processed and refined foods. Those people both would show up as yellow on that omega-3 index test, but they’re clearly not going to have the same risk, at least in my opinion, because it matters a lot where these fatty acids are coming from in the diet.

So I think that the ratio should be taken with a grain of salt, and there’s no reason, in my mind—I’m not convinced that it’s necessary to avoid or restrict omega-6 as it occurs in foods like avocados and nuts and seeds and chicken skin, all of which have a lot of health benefits. What’s interesting is that so many studies show that consumption of tree nuts is inversely associated with heart disease, and those are some of the richest sources of omega-6 fats, so I don’t see a need to restrict omega-6 from those foods, but it is important to get enough omega-3, and the recent studies suggest that fish oil is not the way to do that. They suggest that eating cold-water fatty fish and shellfish is consistently still in studies associated with improved outcomes, both cardiovascular and metabolic, and also improvements in overall health, cognitive function, etc., and they’re pretty significant differences, and that may be because fish does not just contain fish oil; it contains a lot of other beneficial nutrients that are important for humans. And then finally, you would want to reduce your intake of industrially processed vegetable and seed oils because they would tend to be oxidized because they’re heated at high temperatures and they don’t provide a lot of nutritional value.

So there are kind of three things there, and I think if you just get a good amount of omega-3 from food, don’t worry about your omega-6 from nutrient-dense real foods, and limit your omega-6 from industrially processed sources, you’ll be in good shape. It all kind of falls into the category of “eat real food!” I think over the past several years we’ve gotten a little too obsessive about some of this stuff. I never personally saw anyone improve symptomatically by minimizing their intake of omega-6 from real foods, and I don’t think that the research is there to support it.

I hope this answers your question, Daniel. As you said, if you eat a varied paleo diet and avoid excessive amounts of nuts—I don’t think the reason, necessarily, to avoid them is because of the omega-6, but if you’re trying to watch your weight, that might be a reason to moderate your intake—but you should be fine even if your ratio is in the yellow range.

All right, so that’s it for today. Again, if you’re interested in seeing me speak in the UK, you can go to ChrisKresser.com/UKpublic for the public event or ChrisKresser.com/UKclinician for the healthcare practitioner/clinician event. That’s it for today. I’ll see you next time.


Join the conversation

  1. I just came across this article, so I’m joining in late, but I appreciated your thoughts. I also liked a lot of the comments. I just want the standard American diet to keep moving toward more fresh food and not worry so much about supplements…or even what hunters and gatherers ate back in the day.

  2. I’ve just listened to this podcast and I’m pleased to find you’ve reached similar conclusions as myself. What are your thoughts on vitamin D supplementation for those of us in less sunny climates like the UK where it’s difficult to get natural sunshine for most of the year?

  3. Hello Chris,

    Before I ask, just wanted to mention that I’m a huge fan of your work. I have both your books, I’ve read all your ebooks, and have enrolled in your 14 Four program which has done wonders for me. You’ve made a true difference in my life, the improvement is unbelievable. Thank you so much.

    My question is, I’m in the process of healing my gut, fish did not appear as one of my allergens on the IGG tes, but every time I eat it, I flare up, so it’s still out of the question. I haven’t eaten any sources of omega-3 in over a year. I also eat cafo meat, because it’s not available where I live, so I can’t really rely on omega 3 in my meat sources. What would you suggest. Any Canadian brands of fish oil you’re familiar with that you could refer me to? Also, what dosage would you suggest?

    I appreciate your time.
    Thanks again for everything,


  4. Fish oil is one of the few supplements that reduces the feeling of pressure I have in my head because of myalgic encephalomyelitis. The others are vitamin D, calcium AEP and colostrum.

  5. A client of mine with prediabetes eats sources of natural Omega 6 including avocados and nuts as well as fatty fish and shellfish for Omega 3. I added an EFA supplement as well because her HDL has been too low and her triglycerides have been too high.

  6. Hi Chris/Staff,

    Related to this article and the general advice of consuming fatty cold water fish, is there any concern with the radioactive material that is still contaminating ocean water and traveling to places like the Pacific Northwest from Fukashima? I see a Health coach/Nutritionist with a background in radioactive materials and cautioned me about consuming seafood like wild salmon from the Pacific Northwest. Are you aware of any risks or any thoughts about this? I’m not sure if this is too far outside of the scope of the conversation but I’ve been curious if any of the Health experts, especially in the Paleo community, such as yourself are following this.

  7. Chris, my rheumatologist started me on fish oil years ago to help dampen the inflammation in my body from Rheumatoid Arthritis. I take at least 3,000 mg daily. Do you consider this a valid reason to keep taking it?

  8. Chris, I wonder whether you have come across the website http://www.brianpeskin.com? Are there any points of agreement, bearing in mind your reservations about the use of fish oil supplements?
    I would also query our individual needs. Reading about the condition Pyroluria, there seems to be a greater need for healthy Omega 6 oils.

    • Although he is controversial, he is also right and the science is hard to dispute. Some of the biggest names in functional medicine that I have talked to personally have assured me of this, though publicly, they are not commenting because of his controversial nature.

  9. Chris, Regarding omega-6 and seed oil intake, I notice that commercial corn, soybean, sunflower and safflower are mentioned as being bad but what about organic, expeller pressed canola oil such as Spectrum brand? Doesn’t that avoid many of the negatives? Doesn’t canola oil have lower omega 6 compared to those others? I understand it has a MUFA content similar to olive oil. I understand your point that it is best to get any omega 6 you are eating from whole foods rather than oils but I have always considered good canola nearly on a par with olive oil.

    • Avoid canola oil, 80% is GMO and it can’t be cold pressed as the myrosinase enzyme in canola has to be heat inactivated before pressing or it will taste like wasabi. The heating damages the Omega content.

  10. I started eating more pumpkin and sunflower seeds and that made a big difference in how I felt. Now I just take fish oil after I binge on parties like Thanksgiving or Christmas, where I indulge in sweets, munchy snacks and other dietary lapses. The one thing that actually made a big difference in my heart heath was oil pulling with coconut oil.

  11. It may not just be the other nutrients in cold-water fish and shellfish that create better outcomes. From what I’ve read, the processing of fish oil for supplements oxidizes it (along with storage at higher temperatures — these are cold-water creatures); the free radicals would negate any benefits.

  12. Chris, I’ve been avoiding all fish in any form due to the high amounts of mercury and other toxins. Occassionally I will eat small fish like anchovy and some wild caught salmon, but it makes me very uncomfortable. Could you comment on the risk versus benefits of eating any fish consideration the high levels of pollution in the oceans now?

    • Janet,
      I think Chris already wrote about that. Maybe you could search his articles to find it. Sorry I don’t have time to do it and provide you with a link.

  13. Dear Chris,
    I wonder what you think of Dr Kruse`s idea of the primordial importance of DHA. He looks at it from a completely different nutritional perspective.

  14. “The Blue Zones” is a book about the five longest-lived groups of people in the world. In reading about their diets, it’s clear that they’re not super-high in omega-3’s, yet these people consistently live into their 80s, 90s, and past 100.

    The Sardinians eat mostly fava beans, zucchini, tomatoes, potatoes, eggplant, pecorino cheese from grass-fed sheep, bread, goat’s milk, occasional meat (maybe twice a month or less), and red wine (their local wine has 3x the flavonoids of other reds). Homemade bread is by far the main food. These people live in the mountains, so fish isn’t part of the diet. The pecorino cheese is high in omega-3 fatty acids, but that’s about it!

    The Okinawans (the old ones, not the modern city dwellers) eat garden-grown veggies year-round (daikon, bitter melon, garlic, onion, peppers, tomatoes), lots of sweet potatoes, some fish, some tofu, some rice (including millet rice), miso soup, seaweed (kelp, etc.), and herbs like mugwort, turmeric, ginger, and fennel. So fish is what’s giving them the omega-3s here, but from what the book says, the old ones don’t eat a ton of fish, mostly veggies and rice. They have pork maybe once a month, if that. They also have their daily sake.

    The Seventh-day Adventists in Loma Linda, CA, are mostly vegetarian. The ones that do eat meat rarely eat it. They eat a lot of nuts, at least 5 times a week. So these people mostly eat fruits, veggies, whole grains, and nuts. The book didn’t say much about dairy, so I’m not sure how much of that they eat, but it didn’t seem like a lot because it just wasn’t mentioned. Not sure where these people are getting their omega-3s, but they’re living into their 90s and beyond.

    The Costa Ricans (Nicoya) eat mostly corn, beans, squash, garden veggies, an abundance of fruit — and high-sugar fruit at that — (papaya, mango, chico zapote, oranges, and more exotic fruits like maranon and anona), eggs, and occasional pork (and pork fat mixed into rice, etc.). The foundation of the Nicoyans’ diet, however, is homemade corn tortillas, beans, squash, and fruit. So where do the omega-3s come from? I have no idea. Eggs? Pork fat? They even routinely have a cup of heavily sweetened coffee in the mornings and afternoons, and still manage to live into their 90s and beyond.

    And, lastly, the Ikarians (Greece) eat lots of olive oil, veggies, low dairy, low meat (for festivals only), bread, potatoes, goat milk, beans, fruit, and daily wine. There are more than 150 varieties of wild greens that grow on the island that are a big part of their diet. They eat very little fish, because they’re mountain people and the hike down to the water is a long one. They also drink lots of different herbal teas including marjoram, mint, olive leaf, dandelion leaves, etc. They use a lot of honey as a sweetener, sometimes starting the day with a spoonful of honey, as medicine. So, no huge source of omega-3s in this diet, either.

    I think this supports Chris Kresser’s idea about how consuming an overabundance of omega-3s isn’t as important as people thought. None of the traditional diets summarized above have an abundance of omega-3s (they do have some, however), yet these people are the longest-lived in the world with a high quality of life into their 80, 90s, and beyond.

    • Useful summary, many thanks. A clear common denominator is low consumption of meat. I think this is important unless you can be completely sure you are buying grass fed meats and also perhaps if you are not APOE type 4. Despite what all the Paleo pushers may say if you are in doubt adopting a veggie lifestyle with one eye on the potential weak points of pure vegitarianism, will do you no harm. I get regular emails from a veggie group here in the UK and they seem to have no idea what a healthy diet is and yet the core principle is healthful

      • Yes, it’s very confusing to me to read so many things showing the benefits of a paleo diet (including many people’s stories saying they feel so much better on paleo, including people I know, and can actually *see* that they’re doing better), and then read things like “The Blue Zones” that prove that people can be healthy and live very long lives on diets that are relatively meat-free and relatively high in grain consumption.

        Of course, there are other factors at work, like the huge amounts of time these people spend outdoors, moving around, working in their gardens, herding their animals, etc. Also, the tight social networks these societies tend to have, and their reverence for their elders. But when I read that the Nicoyans (Costa Rica) thrive on a diet of mostly corn tortillas, beans, and veggies, that just blew my mind, because corn (grains) and beans (high-carb, allergenic) have been kind of demonized in some health-conscious circles in recent years.

        It’s so hard to know what to believe, but I do agree with you that you could do worse than follow a high veg, very low meat diet like the people described above!

    • This is for Karen in ref. of her Oct. 28, 2015 comment.

      Re. the book “The Blue Zone,” you have to consider “when” this book was published. It does not contain a lot of information that
      we know today, for instance, re. our gut’s Microbiom. (See the many books like Dr. David Perlmutter’s currently on the market discussing this).

      Its to a very significant degree responsible for a vigorous immune system, which in turn combats MANY diseases. (Chrs
      has also made ref. to this!)

      My ancesters come from the Caucasus region in southern Russia where many people lived to be well over 100 years old. I’ve always been told it was probably due to the fermented milk products (like Kefir!) they consumed.

      Today we know that this is a very important source of probiotics which contribute to a healthy microbiom in your gut.

      So, its prossible that NOT only the foods these people ate that the “Blue Zone” book mentions contributed to their longevity, but maybe primarily those that helped the health of their guts!

    • James,

      I did not say anywhere in this podcast that fish oil is inappropriate for all people at all times. I still think it can be useful in some situations, for a limited period of time, at moderate doses. The title of this podcast is “Should everyone supplement with fish oil”, not “Should fish oil be avoided by everyone”.

      Furthermore, if you’ve followed my work for any length of time, you would know that I change my mind and recommendations when new research becomes available. Like many, I used to recommend fish oil for secondary prevention of heart disease, which is one (but not the only) reason that it is in my store.

      • Drug companies get a lot of stick and rightly so for conflicts of interest. It also worries me that we now have a spate of medical advisors coming from a no pharma basis who at the same time are selling their own supp’s. Why should we trust these people any more than the drug companies ?. One thing I like about Esseltyn is that he appears to be giving away nothing other than advice unless he is a paid member of the veg’ marketing board,

      • Hi Chris,

        I very much appreciate that you change your recommendations when new research becomes available. It’s one of the things that really makes you stand out from other practitioners.

        Do you no longer think fish oil is good for preventing heart disease? I tend to get queasy if I try to eat much fish, and I do use plenty of extra virgin unrefined olive oil.

      • I’m happy to see that Chris is open minded regarding FO and CLO. I would suggest that his skepticism should have occurred many years ago. Problems with FO and CLO have shown up in the literature for over 30 years. Being a published researcher myself (not in this field) I recognize good research and I would recommend the papers cited in Ray Peat’s article from around 2004,

        It is quite possible that we the people have been the subjects of a massive PR campaign.

          • One cannot avoid naturally occurring PUFAs in food. One can avoid, however, unnecessary addition of such oils/fats to the foods in one’s diet or as supplements, the long term effects of which are uncertain at best…

            • Well the 2 essential fatty acids are PUFA’s, LA and ALA and supplementing with unadulterated sources of these 2 fatty acids are highly advisable to combat the overabundance of the processed forms of these in our diets.

  15. Chris,

    Here in Columbus Ohio I attended a number of lectures by Dr. Glen F. Aukerman with OSU Integrative Medicine and eventually went through his program. Dr. Aukerman tended to mostly treat terminally ill cancer patients (not me). He had researched this topic extensively in his own practice. There are a number of discoveries I’m not seeing others like you talk about. Not all fish oils are the same. The ratios of DHA and EPA matter a lot. Dr. Aukerman only recommend triple strength fish oil where the ratios of DHA and EPA where higher then the other omega 3 fatty acids, else the oil would only contribute to more omega-6 toxicity. The fish oil should be consumed with other food, and all other sources of high omega-6 oils need removed from you diet. Dr. Aukerman recommended the KIM-2 database from NIH to help develop an balanced omega 3/6 diet. I found that after I completely removing all the bad foods from my diets that I still needed to add daily fish oil to get close to that 1:1:1 balance of omega 3:6:9. Other items Dr. Aukerman pointed out, the ALA found in nuts is mostly converted to omega 6 fatty acids in humans. And, the diets feed to chickens, turkey, and farm raised fish matter as when they are feed diets high in omega-6 fatty acids (aka corn and soybeans) those end up stored in their tissues. Beef and pork are less of an issue because they are able to break down the omega-6 oils.

    That’s interesting you found that fish oil taken with olive oil had the highest benefit. But olive oil also goes rancid over time. Has anyone determined (measured) the rate of rancidity change over time with both olive oil and fish oil at specific temperatures? I keep both my fish oil and olive oil in the refrigerator. I’m assuming that rate of rancidity is reduced by more then a factor of 10 in the refrigerator.


    • First of all, olive oil is an Omega-9 and is non-essential. The fish oil is 320 times more unstable than the true 18 carbon, plant-based versions LA and ALA, so keeping it in the fridge to be swallowed and put in a warm, acidic gut makes no sense. The problem is processing which involves heating of these delicate oils and Omega-6 is the most important one (LA). We need lots of it, in its native state for our cells to function correctly, look it up in any biochemistry textbook.

  16. Recently with the Fish Oil pills I have been having fishy belches through out the day. If studies are showing it’s not beneficial maybe I should switch to other supplements. Do you find that any of the other supplements can give people “flavored belches” through out the day.

  17. Hi I use Krill oil mainly because of the Astaxanthin which I am assuming helps to solve the problem of oxidisation of the oil. Any thoughts on this ?.

    • I’d appreciate a reply on this question as well!!

      I’m concerned that Astaxanthin may be too powerful of an antioxidant to take on a daily basis. I suspect that is may alter the baseline oxidative cycles in your body if you take it over the long term. More antioxidants isn’t necessarily better.

      I’ve heard Dr. Rhonda Patrick suggest that it may be helpful to take a low dose of Vitamin E along with fish oil to prevent potential oxidation of the PUFAs. At 5:30min in the video below, she starts to explain that mega-dosing alpha-tocopherol alone can be problematic. “Mega-dosing” can be considered 10-20x RDA, which is around ~400IU. 400IU tends to be a popular dose of alpha-tocopherol in Vit E supplements.


      I think if you could find a balanced Vit E supplement that isn’t just alpha-tocopherol, and it was close to the RDA…that might be ideal to take alongside a low dose (1 capsule) of fish oil.

    • I am not convinced that daily use of antioxidants of any type is beneficial. In fact, some evidence suggests that ongoing supplementation with high-dose antioxidants may be harmful. A little bit of oxidation stimulates hormesis (positive adaptation), which is probably why antioxidant-rich foods (which are actually mild pro-oxidants) are beneficial, but high-dose supplements may not be.

      • Yes, it looks like antioxidants are a double-edged sword, promoting growth of both cancer and non-cancer cells. Supplements should contain no antioxidants or as little as possible to preserve it’s effects, something fish oil and krill oil cannot do because EPA and DHA are too unstable.

      • So, I eat an avacaco and some nuts ever day along with some fish oil. I take high gamma vitamin e 4-5 times per week to help prevent oxidative damage. Now I wonder about the vitamine e?

  18. Thank you Chris,

    That answered my question, really appreciate you taking the time to explain things further. What’s your thoughts on K2 in regard to supplementation with cod liver oil? Especially now since the fermented variations with K2 from butter oil is not an option.

  19. My ophthalmologist has suggested 2000-4000mg of fish oil daily to help with dry eyes. Are there any studies to support fish/krill oil supplementation alleviates dry eye?

    • Pamela, I used to have a severe dry eye problem, then also a dry mouth problem, so bad that I’d wake up with one side of my tongue stuck to my teeth – in time the surface of my tongue on this side actually came off, leaving it bare and shiny!!
      I thought I was having a really good diet – no processed foods, everything fresh and home cooked. And I was taking a balanced Omega supplement from a reputable company. My optician and dentist were both aware of my problems but could suggest nothing more than eyedrops etc. My GP
      suggested Evening Primrose Oil and it’s all cleared up and I have no further problems with the eyes or mouth. Just shows how individual we all are.

  20. I don’t necessarily take fish oil for my heart but I do take it for inflammation because I have muscle and joint pain on a daily basis. I buy a more expensive one (Shaklee) and find that it really helps the pain and stiffness. I take 6 a day along with a magnesium, vitamin D, B-Complex, COQ10, calcium, vitamin C and multi vitamin. My blood work is always really good so at 65 years of age, I’m sticking with my fish oil!!!

    • Shaklee is only expensive because it’s sold within a pyramid scheme… like Avon. One person sells it and has to make a cut of the profit, but so does his manager; his manager; his manager; the regional managers; the national managers, and the corporate heads. A lot of profit must be built into things that are sold by way of pyramid. I wouldn’t buy anything that is sold where so many people have to profit from it. You’re actually likely getting a very poor product.

  21. I have had nearly lifelong heart palpitations diagnosed as PVCs. The fish oil, when taken regularly, has stopped them. If I go off the fish oil for more than a month the palpitations return. I have been on and off fish oil like this for many years and the phenomena always repeats.

    Preferably, I would rather be eating seafood instead of a concentrated oil. But if the omega 3’s are as delicate as everyone says then how do they survive the cooking process? And what about canned salmon- have the omega 3’s survived the processing?

  22. Hi Chris,
    What about the effects on Fish Oil/FCLO on brain health? And do you think it’s needed while breastfeeding?

    • I still like CLO during pregnancy (and otherwise), but I think of it more as a vitamin A/D supplement with some EPA & DHA.

  23. Chris if someone has histamine tolerance(fish) and can’t tolerate fish oil or FCLO how do they get omega 3? Just wait till the gut is healed?

      • Not all Omega-3s are created equal. Plant sources like Flax Seed have ALA in them, while cold water fatty fish like Salmon contain EPA and DHA. The human body needs EPA and DHA, but is exceedingly inefficient at converting ALA to them (about 6% for EPA and 3.8% for DHA in a very low Omega-6, high saturated fat diet).

        This problem is compounded by the fact that higher Omega-6 consumption *decreases* these already low ALA conversion rates. A 15 gram daily increase (from 15g to 30g) was found in a study to lower the conversion rates by 40 to 50% (which would take EPA down to about 3% and DHA down to about 2%). [1]

        That means, to get the 1.5 grams of DHA per day that you would get from eating 2-3 portions of cold water fatty fish per week, one would need to eat a whopping 75 grams of ALA (which is 675 calories alone). There are roughly 23 grams of ALA per 100g of flax seed, so you’d need to eat about 320 grams of flax seed to get 75 grams of ALA.

        Why did I use the reduced ALA to DHA conversion rate here? Well, because flaxseed has a 1:5 ratio of Omega 6 to Omega 3, which means 320 grams of flax seed also provides 15 grams of Omega 6. As coincidence would have it, a 15 gram increase in Omega 6 was *exactly* what was used in the study I cited above ([1]) that identified the ALA conversion rate decrease caused by higher Omega 6 consumption.

        So how much is 320 grams of flaxseed? Well, that’s 0.7 POUNDS of food and over 1700 calories.

        So, unfortunately, flax seed (or really, ALA in general) is not a viable source of Omega 3s (EPA and DHA) for humans.

        [1] http://www.ncbi.nlm.nih.gov/pubmed/9637947

    • You can get omega-3 from fresh grass fed meats, fresh fish or fish frozen at sea within 30 minutes of being caught (only fish that has not been stored properly will be high in histamine), the fat from grass fed animals’ milk, and butter from grass fed cows. you just don’t want to eat leftover meat (you can freeze it however). I don’t know why fish oil would be an issue.

    • Can you not tolerate EVCLO (non-fermented)? Usually the histamine is produced from protein fraction, not the fat, so I’m surprised if you can’t tolerate the non-fermented EVCLO.

      If you can’t tolerate any fish products at all, you’ll have to use plant-based sources or try an algae supplement (which has pre-formed DHA; that’s where the fish get it).

      • Thanks for the supplements you listed. I will give both of those a try. I really value all your work and I’m slowly overcoming my dysbiosis issues along with SIBO.

  24. A lot of geeky stuff going on here, thank goodness! It still depends on what the source food is fed. Farmed fish fed grains and feedlot animals fed grains will still produce upsets in n3:n6 ratios that carry over to humans, and, potentially, cause health problems, over the long term. Not to mention, of course, those caused by refined, rancid vegetable oils. Chris, keep up the thoughtful and discerning dialogue!

  25. Chris,

    I respect your research, I’ll loosen up on my ratios and look into Chris Masterjohn.

    I will eat a fresh avocado or egg yolk out of the shell before I eat de-shelled nuts but let’s just say I’ve gone extreme with avoiding PUFAs.

    What do you think? I try to avoid nuts because of oxidization and mold.

    • I don’t think the evidence supports extreme avoidance of n-6 PUFA in whole foods. Nor have I seen anyone benefit from avoiding n-6 in whole foods if they were already avoiding n-6 in industrially processed plant/seed oils. Have you seen any difference?

      • I haven’t seen any negative side effects, but I cannot say if I feel significantly better from this one lifestyle change – as I’ve had many in the last few years.

        • The only N-6 PUFA you need is LA. You really can’t avoid it unless you eat a totally processed diet (so it is all adulterated and by now you would be dead). It makes up 33-40% of all cell membranes. It is essential for just this reason. You cannot survive without it.

  26. Dear Chris
    Can everyone agree that the research on omega 3 supplementation is patchy? I would like to put forward one explanation based on biochemistry for people then to apply to studies for themselves.
    Firstly I tried to look at the 5 studies which you mentioned in your June Article about heart health (not atrial fibrillation), but could only get details on the three of them, numbers 2,3,and 7. (Personally for atrial fibrillation, papers 4,5,6, I would look to free glutamate research, a neurotransmitter). The three papers just add to the patchy nature and the conclusions do not stand up well. Number 2 had only 600mg of EPA and DHA and no other diet or medication information (important as you will see from the biochemistry facts later). The number 3 was margarine supplementation and only 376 mg of EPA and DHA and again no diet info (could assume bread or toast probably consumed) and no info on trans fats. Study 7 was correctly criticised by the Journal of the American Medical Association for example, for 10 of 14 studies being only 2 years or less which is when the survival curve started to diverge in the GISSI study. Also interestingly 5 of the trials used olive oil instead of a true placebo. Etc.

    Now the biochemistry. 1) The conversion enzyme, delta 5-desaturase, is competed for by omega 3 (EPA) and omega 6 (DGLA) to produce hormones. However that conversion enzyme is also affected by high insulin levels. Omega 3 (EPA) limits the amount of Arachidonic Acid (AA) that this conversion enzyme produces. AA is an omega 6 responsible for the pro-inflammatory eicosanoid hormones (as well as a few good ones). High insulin boosts this conversion enzyme and hence it pushes the conversion in favour of AA. So it is not just the ratio of EPA and DGLA in isolation if insulin is not balanced.
    Hormones act in interconnected systems, insulin also boosts an enzyme (HMGR) which produces cholesterol. So by having controlled insulin levels it helps to balance both the Eicosanoid hormones (made from omega 3 & 6) and cholesterol.
    2) The hormone production from long chained omega 3 and omega 6 is also messed up by trans fats and by some medication. The last point is relevant here as far as statins are concerned. Statins reduce the enzyme HMGR lowering cholesterol, but this is largely irrelevant as they actually work in a very complex fashion including via the eicosanoid system decreasing inflammation. Other drugs designed to work on the eicosanoid system are corticosteroids and NSAID pain killers, temporarily blocking the pro-inflammatory ones (but also blocking the good ones, hence the side effects).

    Now apply this biochemical knowledge to mass clinical trials. You will see from the classic highly successful Lyon diet heart study. Initially everyone thought the magic bullet was the 3 times increase in omega 3 in the Mediterranean diet trial group. But reassessing it (see http://www.slideshare.net/pronutritionist/lyon-heart-study ) you will find that actually the omega 6 was also reduced such that the ratio changed by 4.4 times (from 19.6 to 4.4). Also the omega 3 population group only gained 1kg verses 3kg in the standard French diet control group which to me indicates better insulin control. Interestingly the oils for salads for the Mediterranean diet group were exclusively olive oil or rapeseed oil. (You mentioned anti-oxidants etc. and there is hunger control via the CCK hormone). Finally no one in the study was on statins.

    Omega 3 is essential as the hormones called Resolvins (and Protectin and Maresin) can only be made from long chained omega 3 and these bring inflammation to an end (just google Harvard and Resolvins). I believe that long chained omega 3 does need to be assessed relative to omega 6 intake, but without understanding a person’s insulin levels you will get highly variable results. Then add trans fats, statins (and most pain killers and asthma drugs) and you get greater variety as these impact on the same system. Given these biochemical facts then you can only predict that omega 3 studies not incorporating these factors will be patchy. The reason that the Lyon diet heart study worked so well was that it was changing more than just fish oils.
    A final comment, quality of ingredient is important, added omega 3 in foods will often be poor quality short chained omega 3. The ratio is probably fine up to around 6:1 if insulin is ok and not on certain medication, hence walnuts are fine etc. Also as the omega 3 and 6’s are stored in membranes it can be assessed in total consumption over day or more, hence I regularly build in almonds to my diet. Where omega 3 intake is high more omega 6 can be consumed as well. The real key to the omega 3 / 6 debate is all about a low inflammatory diet, and that is a combination of omega 3 /6 control, not damaging omega 3 (storage & high temps), plus insulin control (e.g. Dr Barry Sears), and not antagonising the body e.g. with gluten (Dr Pulmutter ) or free glutamate (Dr Katherine Reid) if you are sensitive. Control insulin, the eicosanoid system, the master detox and anti-oxidant system (Gluthathione) avoid your personal allergic foods for a good gut, then add exercise and seek low stress and you have a powerful answer. Difficult – no, we were born that way, and if we eat normal food and behave how we used to it works! Thanks to Chris for making the enormous effort to pull this all together for readers. I just wish I could make your appearances here in London.

    • I completely agree Paul. Starting our research from a product base with a high risk of oxidation http://www.nature.com/articles/srep07928 and ignoring previously explored dose and ratio dependencies makes for bad science. It is also interesting that you mention the relationship with insulin and eicosanoid system. In Sweden we use omega-3 (in high polyphenol olive oil) in working with sugar additions because of the the effects on specifically the endocannabinoid system (an eicosanoid) and leptin.

  27. Hi Chris,

    whenever I tried to supplement fish oil, I ended up with nose bleed and bursted blood vessels in my toes after a certain amount of time (weeks).

    I’m done with fish oil. I think it’s even risky for me.


  28. Forget about fish oil, think about Linseed oil (cold pressed raw)
    contains 10x more Omega 3, you would have to eat five 8oz
    fish per day, to one tsp of Linseed oil, and it’s great for the skin
    / hair and digestive system! I give it to my horse and I take it my-
    self every day and neither of us looks their age!!

    You may respond to this comment if you so wish.

  29. In regards to omega 3’s, I have always wondered how traditional human populations that had no access to cold water fish and shellfish got their dose of omega 3’s. I’m thinking Australian Aborigines living in inland arid environments, native Americans and inland dwellers of the African continent. Any thoughts?

    • In her book, “The Jungle Effect”, Daphne Miller discusses a land-locked area where the inhabitants had OK levels of Omega-3s. It was discovered they were eating pasture-raised lamb and getting them this way.

    • I’ve always wondered about this, too. I wrote a related post (the really long one, closer to the top of the comments 🙂 talking about the five longest-lived groups of people in the world (according to a National Geographic study). Only one of them (Okinawans) regularly ate seafood. Several of these groups don’t have high omega-3 consumption, yet they are healthy enough to live into their 80s, 90s, and beyond with a high quality of life (ie; still working, living independently, etc.).

  30. Omega six from your natural diet is fine, but the omega six processed oils is out of balance particularly here in New Zealand and has created inflammation in a number of clients but there have certainly been major improvements when restricting this with inflamed joints and connective tissue, increasing omega three also appears to assist recovery.

  31. What about someone who can’t handle eating much fish (it tends to make me queasy)?

    I’ve been taking about 4 g of fish oil. I don’t eat any processed foods, nuts, or seeds, and I do use extra virgin unrefined olive oil.

  32. Hi Chris, I always want to seek for the truth and I have to say that you arose a very good point among the paleo community. I love chicken skin and let’s be honest, it’s the most delicious part, instead of the rubbery dry breast. To be honest I was worried to get too many omega 6 but at the same time I’ve been wondering why so tasty real foods that as hunter gatherers we were likely to eat a lot in the wild could be so harmful for our health. Now I’m happy to hear again the same lesson, that it’s much more about food than a single nutrient. In cold fish you don’t find only omega3, but a ton of synergistic molecules that play together as a band. You can’t isolate a single member of a band, make him play alone and expect to have the same result. Isolated fish oil tend to oxidize and you lose the benefits of eating real food. Ironically enough, it’s odd to hear from paleo advocates such great amounts of supplements, from people whose purpose is exactly the opposite, i.e. advocating the importance of real stuff you could find in nature, real living food instead of pills. Food is much more than the sum of its molecules like living beings are much more than some pieces of flesh put together in some way.

  33. re: There is not much evidence to support that taking fish oil in that population will really do much of anything.

    In the context of what diet(s)?

    I suspect that most if not all available population data is based on SAD (or the diet is unknown, and may be presumed to be SAD), and that detail is also lacking on genetic factors (like FH) and confounders like microbiome status. Fish oil for SAD? I would have guessed neutral or negative.

    What would be really valuable is outcome data, at 0, 1, 3 and 6 grams/day DHA&EPA, for people doing paleo-style diets (ideally grain-free, VLC, and high specific fats – no added inflammatory industrial oils). I don’t frankly expect to see such data soon. In the meantime, we all need to place our personal bets, and keep an eye on labwork.

    • Jeff,

      For the record, I still do think 1/2 tsp of cod liver oils is a good choice for those that aren’t eating organ meats or getting enough vitamin D.

      Other than that, I’ve never really recommended standard fish oil as a supplement for most people.

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