How Too Much Omega-6 and Not Enough Omega-3 Is Making Us Sick

How Too Much Omega-6 and Not Enough Omega-3 Is Making Us Sick


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In the last article we discussed the problems humans have converting omega-3 (n-3) fats from plant sources, such as flax seeds and walnuts, to the longer chain derivatives EPA and DHA. Since EPA and DHA (especially DHA) are responsible for the benefits omega-3 fats provide, and since EPA and DHA are only available in significant amounts in seafood, it follows that we should be consuming seafood on a regular basis.

But how much is enough? What does the research literature tell us about the levels of EPA and DHA needed to prevent disease and ensure proper physiological function?

I’m going to answer this question in detail in the next article. But before I do that, I need to make a crucial point: the question of how much omega-3 to eat depends in large part on how much omega-6 we eat.

Over the course of human evolution there has been a dramatic change in the ratio of omega-6 and omega-3 fats consumed in the diet. This change, perhaps more than any other dietary factor, has contributed to the epidemic of modern disease.

The historical ratio of omega-6 to omega-3

Throughout 4-5 million years of hominid evolution, diets were abundant in seafood and other sources of omega-3 long chain fatty acids (EPA & DHA), but relatively low in omega-6 seed oils.

Anthropological research suggests that our hunter-gatherer ancestors consumed omega-6 and omega-3 fats in a ratio of roughly 1:1. It also indicates that both ancient and modern hunter-gatherers were free of the modern inflammatory diseases, like heart disease, cancer, and diabetes, that are the primary causes of death and morbidity today.

At the onset of the industrial revolution (about 140 years ago), there was a marked shift in the ratio of n-6 to n-3 fatty acids in the diet. Consumption of n-6 fats increased at the expense of n-3 fats. This change was due to both the advent of the modern vegetable oil industry and the increased use of cereal grains as feed for domestic livestock (which in turn altered the fatty acid profile of meat that humans consumed).

The following chart lists the omega-6 and omega-3 content of various vegetable oils and foods:

efa content of oils

Vegetable oil consumption rose dramatically between the beginning and end of the 20th century, and this had an entirely predictable effect on the ratio of omega-6 to omega-3 fats in the American diet. Between 1935 and 1939, the ratio of n-6 to n-3 fatty acids was reported to be 8.4:1. From 1935 to 1985, this ratio increased to 10.3:1 (a 23% increase). Other calculations put the ratio as high as 12.4:1 in 1985. Today, estimates of the ratio range from an average of 10:1 to 20:1, with a ratio as high as 25:1 in some individuals.

In fact, Americans now get almost 20% of their calories from a single food source – soybean oil – with almost 9% of all calories from the omega-6 fat linoleic acid (LA) alone! (PDF)

This reveals that our average intake of n-6 fatty acids is between 10 and 25 times higher than evolutionary norms. The consequences of this dramatic shift cannot be overestimated.

Omega-6 competes with omega-3, and vice versa

As you may recall from the last article, n-6 and n-3 fatty acids compete for the same conversion enzymes. This means that the quantity of n-6 in the diet directly affects the conversion of n-3 ALA, found in plant foods, to long-chain n-3 EPA and DHA, which protect us from disease.

Several studies have shown that the biological availability and activity of n-6 fatty acids are inversely related to the concentration of of n-3 fatty acids in tissue. Studies have also shown that greater composition of EPA & DHA in membranes reduces the availability of AA for eicosanoid production. This is illustrated on the following graph, from a 1992 paper by Dr. William Landis:

percentage of n-6 and n-3 in tissue associated with

The graph shows the predicted concentration of n-6 in the tissue based on dietary intake of n-3. In the U.S. the average person’s tissue concentration of highly unsaturated n-6 fat is 75%.

Since we get close to 10% of our calories from n-6, our tissue contains about as much n-6 as it possibly could. This creates a very inflammatory environment and goes a long way towards explaining why 4 in 10 people who die in the U.S. each year die of heart disease.

(Note: the ratio of omega-6 to omega-3 matters, but so does the total amount of each.)

In plain english, what this means is that the more omega-3 fat you eat, the less omega-6 will be available to the tissues to produce inflammation. Omega-6 is pro-inflammatory, while omega-3 is neutral. A diet with a lot of omega-6 and not much omega-3 will increase inflammation. A diet of a lot of omega-3 and not much omega-6 will reduce inflammation.

Big Pharma is well aware of the effect of n-6 on inflammation. In fact, the way over-the-counter and prescription NSAIDs (ibuprofen, aspirin, Celebres, etc.) work is by reducing the formation of inflammatory compounds derived from n-6 fatty acids. (The same effect could be achieved by simply limiting dietary intake of n-6, as we will discuss below, but of course the drug companies don’t want you to know that. Less profit for them.)

As we discussed in the previous article, conversion of the short-chain n-3 alpha-linolenic acid (ALA), found in plant foods like flax and walnut, to DHA is extremely poor in most people. Part of the reason for that is that diets high in n-6 LA inhibit conversion of ALA to DHA. For example, one study demonstrated that an increase of LA consumption from 15g/d to 30g/d decreases ALA to DHA conversion by 40%.

Death by vegetable oil

So what are the consequences to human health of an n-6:n-3 ratio that is up to 25 times higher than it should be?

The short answer is that elevated n-6 intakes are associated with an increase in all inflammatory diseases – which is to say virtually all diseases. The list includes (but isn’t limited to):

  • cardiovascular disease
  • type 2 diabetes
  • obesity
  • metabolic syndrome
  • irritable bowel syndrome & inflammatory bowel disease
  • macular degeneration
  • rheumatoid arthritis
  • asthma
  • cancer
  • psychiatric disorders
  • autoimmune diseases

The relationship between intake n-6 fats and cardiovascular mortality is particularly striking. The following chart, from an article entitled Eicosanoids and Ischemic Heart Disease by Stephan Guyenet, clearly illustrates the correlation between a rising intake of n-6 and increased mortality from heart disease:

landis graph of hufa and mortality

As you can see, the USA is right up there at the top with the highest intake of n-6 fat and the greatest risk of death from heart disease.

On the other hand, several clinical studies have shown that decreasing the n-6:n-3 ratio protects against chronic, degenerative diseases. One study showed that replacing corn oil with olive oil and canola oil to reach an n-6:n-3 ratio of 4:1 led to a 70% decrease in total mortality. That is no small difference.

Joseph Hibbeln, a researcher at the National Institute of Health (NIH) who has published several papers on n-3 and n-6 intakes, didn’t mince words when he commented on the rising intake of n-6 in a recent paper:

The increases in world LA consumption over the past century may be considered a very large uncontrolled experiment that may have contributed to increased societal burdens of aggression, depression and cardiovascular mortality.

And those are just the conditions we have the strongest evidence for. It’s likely that the increase in n-6 consumption has played an equally significant role in the rise of nearly every inflammatory disease. Since it is now known that inflammation is involved in nearly all diseases, including obesity and metabolic syndrome, it’s hard to overstate the negative effects of too much omega-6 fat.

In the next article we’ll discuss three different methods for determining healthy intakes of n-3 that take background intake of n-6 into account.


Join the conversation

  1. Get your facts straight. You are spewing complete misinformation. EPA and DHA are not essential fatty acids.

    The only essental fatty acids are ALA and LA. We need more PARENT omega 6 . Look into Brian Peskin. SCIENCE , NOT opinion.

    • Read the articles and the studies I cited. I’ve read Peskin. I’ve also read hundreds of studies that contradict his view. The entire point of this series of articles is that the FAs considered to be essential are not essential. You might want to actually read an article before you leave a comment on it.

  2. Roger,

    Below is a response from a communication I had with Stephan Guyenet from Whole Health Source about this study:

    Regarding omega-6. There are a few issues here. One is the studies that show that the people who eat the most n-6 “have the least inflammation”. IIRC, he’s talking about observational studies showing that people with the highest n-6 intake have lower levels of circulating markers of inflammation. First of all, it’s highly susceptible to “healthy user bias”; as I’m pretty sure if you looked at those studies most of the smokers would be in the low n-6 category. These studies are typically conducted in populations in which nearly everyone has an excessive n-6 intake and a poor n-6:3 balance, so it’s hard to make any broad conclusions. But also, circulating markers of inflammation (CRP, IL-6 etc) really are a poor surrogate for tissue inflammation, which is much more complex and difficult to measure.

    He mentions that some n-6 eicosanoids are involved in resolving inflammation, which is true. However, n-3 are involved in it as well. The more n-6 you eat, the more it blocks EPA and DHA production from ALA, which you need to make inflammation-resolving n-3 eicosanoids. So even though you still have the resolving n-6 eicosanoids, that’s only half the puzzle.

    By the way, I think there are also likely to be negative effects of excess n-6, and particularly veg oils, on health that don’t depend on eicosanoids.

  3. He kindly sent me a PDF of the article.  It says “Author’s Personal Copy” on it, so I don’t think I should post it, but send me an e-mail address and I will forward it.

  4. I couldn’t find the full article anywhere either!     But according to WorldCat / ScienceDirect , it’s available for library use only at a nearby University.  Hopefully, they have a copy machine!
    Incidentally, that author, Kevin Fritsche, seems to have published other worthwhile  articles:
    The adverse effects of an in vivo inflammatory challenge on the vitamin E status of rats is accentuated by fish oil feeding:
    Omega-3 polyunsaturated fatty acids impair in vivo interferon- gamma responsiveness via diminished receptor signaling:

  5. Looks interesting, but without access to the full text I can’t comment on it.  I can say that there is a large body of evidence supporting the pro-inflammatory role of LA, both in vitro and in vivo.

  6. My opinion is that you do not need much poly-unsaturated fatty acids at all. When you consume somewhere between 0.5 and 3 grams per day it’s more than enough. You easily get that out of real foods. So you don’t need sead oils or fish oils. I made a little video on the subject:

  7. Can you say something about the n-6 / n-3 ratio of pastured beef, pork, lamb, chicken, and goat, as well as pastured eggs?

    Your site is FANTASTIC!

    Thank you,

    • Kevin,

      Glad you like the site! Check out this chart comparing fatty acid profiles of grass-fed and grain-fed beef. Also see this study. Most of the evidence shows a higher concentration of n-3 and a lower concentration of n-6 in grass fed meat. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries.

      Hope that helps,

    • Lots of the smaller fish have undetectable levels of Mercury and other toxins.

      These low-level fish have short life spans and do not consume things that have high levels of toxins.

    • Krill is low on the food chain and doesn’t contain mercury or PCBs. And it’s more potent than regular fish oil. Try it as a supplement.

  8. Grass-fed meat has more n-3 than factory-farmed meat.  The difference is very small, but it’s there.

    Our ancestors likely got EPA & DHA from seafood and consuming the brains of ruminants.

  9. I ignored it on purpose.  I don’t believe they’re anywhere near as important as the n-3 and n-6, and not at all as common in the diet.

  10. Your point on Omega-3s, -6s, and -9s ignores the Omega-7s.  I don’t know much about them, as they have only come to my attention recently, but they are there…

  11. The article only mentioned fats from oils, and neglected fats from animal tissue.  Mammals and birds are also 100% deficient in Omega-3.  The primary fatty acid in beef is Arachidonic Acid, an Omega-6.  It has been found that many vegetarian societies are actually deficient in this fatty acid, yet most Americans are flooded with it.  As with most substances, too much is as bad or worse than too little.

  12. The more unsaturated an oil is, the more easily it oxidizes.  Flax is omega-3, which is very unsaturated.  That’s why it’s imperative never to cook with it.  In fact, it must be stored in the refrigerator in opaque containers to prevent oxidation from light and heat.  There’s no reason to consume flax oil anyways, as I stated before.

    The best fats to cook with are saturated, because they’re relatively protected against oxidation.  Coconut oil, butter, ghee, and animal fats like tallow are all good choices.

    Olive oil is less inflammatory than omega-6 oils, but still has a significant amount of omega-6 so should be used in moderation.

    • “There’s no reason to consume flax oil anyways, as I stated before.”

      Have you heard of or studied the work of Johanna Budwig? Her whole life’s work was spent on this topic and she no doubt, and many others, myself included, take exception to such a profound pronouncement. Check it out sometime.

      • This doctor needs to meet doctor Michael Gregor…who speaks extensively on flaxseed.. It sounds like this site is against plant based diet which makes it quite one sided

  13. Just to add to the list,  Olive oil is mostly Omega-9, with only about 10% omega-6.     Grape Seed Oil  (popular in Chile),  is mostly (~75%) omega-6.
    So what about Omega-9s?   How does it relate to Omega-3s?   Is it also pro-inflammation?
    Due to the lower omega-6 content, I would think Olive or Flaxseed oil (or even Canola) would be the ideal cooking oil, yet I don’t often hear it touted for cooking.. why?    The relatively low smoke temperature (200’s F)?

    • I am learning that oils with low smoke temp can be used at lower heats on stove to saute vegetables and do cooking. It is new for me as I have always done stir frys at high temperatures. Learning how to use oils and stove more effectively, even at my age. Hope this creates awareness and thinking. Open to comments.

    • The some point of extra virgin olive oil is 200 celsius/centigrade and NOT 200 Farenheit
      Olive oil has one of the highest smoke points (avocado is higher).
      All refined vegetable oils have a higher smoke point compared to their corresponding cold pressed.
      To compare, butter has ca 150 centigrade.

    • When cooking with oils at high temps it is tuned into rancid inflammatory oxidized poison. Look into avocado oil for it’s high temp resistance.
      Who recommends canola, that is some old tech people? that stuff is so bad highly refined and rancid as it sits on the shelf. My joints hurt just thinking about it.
      Soy? xenoestrogens, phytoestrogens. Man boobs and early puberty for girls- hormone disrupters.
      Antibiotics used in dairy cows by the gallons, are helpful in creating multi drug resistant organisms that are rampant now, thanks for that. and everything is fed with GMO corn. Cows, chickens, fish. If you don’t eat organic grass fed and finished, free range, and wild caught, who knows what you’re eating? And now all the oceans are poisoned and radioactive? Now what? Oh our lovely flouridated chlorinated drinking water yeah.

    • I would avoid canola oil since most are GMO. I doubt if they are labeled so it is Russian Roulette to use them.

  14. Jeff,

    I’m not sure what the asterisk means.  I pulled that graphic from a website a while back and now I can’t find it.

    Olive oil is between 55 and 83% omega-9 (monounsaturated), and 3.5 and 21% omega-6 (polyunsaturated).  The fatty acid content varies by the region where it’s produced.

    On average, according to Wikipedia, olive oil contains 11% omega-6 LA.  That is still quite high, which is why I only recommend olive oil in moderation.

    The best fats to consume and cook with are those that are the most saturated: butter, coconut oil, ghee, tallow, duck & goose fat.  Pretty much the opposite of what we’ve been told.

    • I would assume the asterisk is meant to clarify that fish oil is high in n-3 when it is caught in the wild instead of farmed. 🙂

      • Why is farm-raised fish missing omega 3?
        What ocean fish, sourced from what countries, do you recommend?

        • I take Laminine Omega. LPGN sources its fish oil from Engraulis Ringens, a member of the anchovy family, found in the Humboldt Current off the coast of South America near Peru, where the waters are clean and clear. Phytoplankton that the Engraulis Ringens species consumes in this region is rich in DHA and EPA, giving the fish the highest naturally occurring ratios of DHA and EPA of any other fish species. The fish oil also undergoes molecular distillation, and is tested before and after the process to remove gunk and toxins and ensure the safety of the oil.

          It is patented and has Omega fatty Acids 3 (EPA and DHA),CoQ10(Extended Release), Vitamin K2… It is made in USA; head office is in California. That’s why delivery and handling is free in the States and to me it is convenient. Delivery varies from 3 to 8 days. I found this online and have been ordering it online as well . You click Join if you want to be a member and get the member’s price Or click retail order if you don’t want to be a member.

          So far, I’m very satisfied with this product.

        • sandi lampiris asked:
          “Why is farm-raised fish missing omega-3?”

          That all depends what the fish are fed. If they are fed grain (e.g. corn) based feed, then it will be high in omega-6. If they are fed fish meal from fish that ate omega-3-rich algae, then they will have the expected omega-3’s but still be likely to consume a lot of antibiotics, growth hormones, effluents, and local land-based pollutants. (Does anybody have solid data on fish feeds???)

          • Commercial fish feed
            The first 10 ingredients of Skretting’s “Winter Plus 3500″ salmon feed lists these as the first nine ingredients:
            Poultry Meal, Fish Meal, Poultry Fat, Fish Oil, Whole Wheat, Soybean Meal, Corn Gluten Meal, Feather Meal, Rapeseed Oil.
            The whole label is here:

            Note the chicken products. According to a doctor (Who did not give any references) the avian flue in migrating birds that arrived on US shore, was from birds who’s rout took them over areas where they farm fish. The fish had been fed the farmed chickens that got it and were disposed of that way.
            This could be just a conspiracy story.

    • Clearly that graph is a bit misleading, fish most certainly has omega-6 PUFAs, although yes usually in pretty high 3 to 6 ratios. Just look on or or somewhere, not hard.

    • I would believe that the asterisk means only wild caught fish, since farmed fish are being fed diets similar to grain-fed cattle and pigs, thus the ratio of their fat will lean more towards omega 6. Another thing of note is that animals eating a more natural diet (rotational grazing) have fat much higher in omega 3.

    • Hi Chris,
      When I live din south-western France, I was a big fan of goose and duck fat — until I realized that modern ducks and geese are fed corn! (Which has no omega-3 and is high in omega-6).
      As for ghee, I’m concerned by reports that modern dairy fat contains high concentrations of estrogens because dairy cows are milked while pregnant (when their estrogen levels are 13 times higher than when they’re not…). One study published last year found that breast cancer survivors consuming high-fat cows’ milk foods had a higher risk of dying from breast cancer than women eating little to no high-fat dairy. (I wrote about this here: What do you make of this?
      Thanks & best, Conner

    • Hi, I’m trying to figure out why I’m getting more ill with Autoimmune disease. Type 1 diabetes, lupus, Hashimotos….I try to eat right but am getting worse. I think either our food or the meds I take are poisoning me…making my body attack itself. I’m having problems with toxic levels of triglycerides…over 1200 last month. I’m a nurse no longer working due to my conditions….spend much time trying to figure out what is going on with me. I have just found this site and hope you could help me. I try to eat a “healthy” diet with lots of whole grains, only use olive oil, rarely eat meat but do use dairy…my go to for protein is cheese. I also love to snack on pumpkin seeds with the shell…fiber? Anyway, I’m having increasing triglycerides….could it be the liberal use of olive oil. They are trying me on high dose fish oil but I just realized my horrible abdominal pain is being caused by this. Crestor and the other statins cause my already overwhelming muscle pain to become unbearable. I’m running out of options. Feel like I need to go somewhere and live in a health “rehab” type environment to figure it out. Help?!

      • I lowered my triglyceride levels ( from 300 to 89 in 6 months) by cutting out all white foods except cauliflower. No grains, sugar ( which is highly inflamatory) or white potatoes. I have lost 25lbs over that six months and lowered my HgA1C from 9.6 to 6.6. Try it and see if that helps. Eat lots of veggies, cheese, eggs, and grass fed meat if at all possible. I know it is more expensive but you can eat less and eat well. The fats help with satiaty.

      • Hi Pam,
        Your symptoms sound very similar to the documentary I just watched, and the guy cured all his autoimmune, inflammation, and obesity issues by drinking nothing but vegetable juice. It’s on Netflix: Fat, Sick, and Nearly Dead (sorry for the title). I’m personally more a proponent of eating lots of veggies, rather than juicing, but it worked for him. Also I just read that pumpkin seeds are ultra high in n-6, so inflammatory. Good luck and hope you feel better!

      • If you will read Dr Esselstyn’s book called preventing and reversing heart disease and follow his diet exactly your triglycerides and total chlolesterol will drop like a rock and many of your health problems will go away over time. He has saved many people with major heart disease only by following his diet. Google his name and listen to his presentations on Youtube. I wish you the best.

      • You will do better to get the grains/starches completely out of your diet. I also have autoimmune issues, Hashimoto’s among them. I was having terrible intestinal issues, came close to losing part of my colon from infection. I have seen a dramatic improvement in my situation by going completely grain-free. Joint pain gone, blood pressure normalized, sleep greatly improved.

        Modified “primal” eating has been a god-send.

      • Excellent article. To help Pam Butler I suggest reading The OmegaRx Zone by Dr Barry Sears. To get the real maximum from the omega3 you need to control insulin levels first. It explains that you can take the guess work out by measuring your AA to EPA ratio (maintain 1.5 to 3 but note this is of plasma not cells). It sounds like you could have too many carbohydrates. Secondly check for gluten sensitivity (not the same as full blown coeliacs ) and read The Grain Brain by David Perlmutter. As Chris kresser says, the inflammation affects many diseases. I came at it from cancer research, the first author Dr Sears from cardiac disease and the second author from neurology. Thanks again Chris, I hope this helps.

      • Hi Pam, there’s a clue in your comment to what may be wrong. You mention taking statin drugs, and then say that your health is getting worse and worse. Could the statins be causing your problems? Specifically, statin drugs interfere with CoQ10, which is absolutely essential for health. If I were on statins, or had been on them in the past, I would immediately start dosing with CoQ10 and its activated form, ubiquinol.

        Also, unless your cholesterol levels are ten times higher than normal, are you absolutely sure you need statins? They are often overprescribed, and can do a great deal of damage.

        Apart from that, if I were in your situation, just speaking personally not professionally, I would do these things:

        • take organic non-hydrogenated coconut oil every day
        • stop using the olive oil for a couple of months
        • switch to liquid fish oil from Carlson (the purest)
        • add chia seeds soaked in water to my diet (for chia oil)

        Good luck, I hope you experience improvement.

      • Hi Pam-
        I don’t know if you’ll see this, but if you’re anywhere near the state of Oklahoma, there is a phenomenal doctor in Tulsa that may be able to help you. His name is Dr. Roadhouse. Hope you feel better soon!

      • Pam I would try it without the grains for a week and look into the fodmap diet. a lot of different types of healthy fiber cause problems for some people. The healthier they go the sicker they feel. I’m not medically trained just a possibility for you to look at.
        Also Lyme disease does a lot of weird things and is often misdiagnosed.
        Good luck!

    • Thank you for the great articles. For optimal Omega-3, would you recommend avocado oil or coconut oil for cooking. I’ve been cooking on ghee and avocado oil, and was wondering if coconut oil is even better than avocado. thank you

  15. Chris,
    What is the asterisk (on fish oil) indicating in the table?  Also, I would love to see more discussion on olive oil.
    I don’t use vegetable/corn oil in my home cooking at all, although I haven’t checked how much I am exposed through buying processed/restaurant food.

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