How Much Omega-3 Is Enough? That Depends on Omega-6. | Chris Kresser
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How Much Omega-3 Is Enough? That Depends on Omega-6.

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In the first article of this series, 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. In the second article, we discussed how excess omega-6 (n-6) in the diet can block absorption of omega-3, and showed that the modern, Western diet contains between 10 and 25 times the optimal level of n-6.

In this article we’ll discuss strategies for bringing the n-6 to n-3 ratio back into balance. There are two obvious ways to to do this: increase intake of n-3, and decrease intake of n-6.

Many recommendations have been made for increasing n-3 intake. The important thing to remember is that any recommendation for n-3 intake that does not take the background n-6 intake into account is completely inadequate.

It’s likely that the success and failure of different clinical trials using similar doses of EPA and DHA were influenced by differing background intakes of the n-6 fatty acids. In the case of the Lyon Diet Heart Study, for example, positive outcomes attributed to ALA may be related in part to a lower n-6 intake (which would enhance conversion of ALA to EPA and DHA).

This explains why simply increasing intake of n-3 without simultaneously decreasing intake of n-6 is not enough.

Bringing n-3 and n-6 back into balance: easier said than done!

Let’s examine what would happen if we followed the proposed recommendation of increasing EPA & DHA intake from 0.1 to 0.65g/d. This represents going from eating virtually no fish to eating a 4-oz. serving of oily fish like salmon or mackerel three times a week.

The average intake of fatty acids (not including EPA & DHA) in the U.S. has been estimated as follows:

  • N-6 linoleic acid (LA): 8.91%
  • N-6 arachidonic acid (AA): 0.08%
  • N-3 alpha-linolenic acid (ALA): 1.06%

Keep in mind from the last article that the optimal ratio of omega-6 to omega-3 is estimated to be between 1:1 and 2.3:1. Assuming a median intake of n-6 (ALA + LA) at 8.99% of total calories in a 2,000 calorie diet, that would mean a daily intake of 19.9g of n-6. If we also assume the recommended intake of 0.65g/d of EPA and DHA, plus an average of 2.35g/d of ALA (1.06% of calories), that’s a total of 3g/d of n-3 fatty acid intake.

This yields an n-6:n-3 ratio of 6.6:1, which although improved, is still more than six times higher than the historical ratio (i.e. 1:1), and three times higher than the ratio recently recommended as optimal (i.e. 2.3:1).

On the other hand, if we increased our intake of EPA and DHA to the recommended 0.65g/d (0.3% of total calories) and maintained ALA intake at 2.35g/d, but reduced our intake of LA to roughly 7g/d (3.2% of total calories), the ratio would be 2.3:1 – identical to the optimal ratio.

Further reducing intake of n-6 to less than 2% of calories would in turn further reduce the requirement for n-3. But limiting n-6 to less than 2% of calories is difficult to do even when vegetable oils are eliminated entirely. Poultry, pork, nuts, avocados and eggs are all significant sources of n-6. I’ve listed the n-6 content per 100g of these foods below:

  • Walnuts: 38.1g
  • Chicken, with skin: 2.9g
  • Avocado: 1.7g
  • Pork, with fat: 1.3g
  • Eggs: 1.3g

It’s not too hard to imagine a day where you eat 200g of chicken (5.8g n-6), half an avocado (1.1g n-6) and a handful of walnuts (10g of n-6). Without a drop of industrial seed oils (like safflower, sunflower, cottonseed, soybean, corn, etc.) you’ve consumed 16.9g of n-6, which is 7.6% of calories and far above the limit needed to maintain an optimal n:6 to n:3 ratio.

Check the chart below for a listing of the n-6 and n-3 content of several common foods.

Click the thumbnail for a larger version

Ditch the processed foods and cut back on eating out

Of course, if you’re eating any industrial seed oils you’ll be way, way over the optimal ratio in no time at all. Check out these n-6 numbers (again, per 100g):

  • Sunflower oil: 65.7g
  • Cottonseed oil: 51.5g
  • Soybean oil: 51g
  • Sesame oil: 41.3g
  • Canola oil: 20.3g

Holy moly! The good news is that few people these days still cook with corn, cottonseed or soybean oil at home. The bad news is that nearly all processed and packaged foods contain these oils. And you can bet that most restaurant foods are cooked in them as well, because they’re so cheap.

So chances are, if you’re eating foods that come out of a package or box on a regular basis, and you eat out at restaurants a few times a week, you are most likely significantly exceeding the recommended intake of n-6.

Two other methods of determining healthy n-3 intakes

Tissue concentration of EPA & DHA

Hibbeln et al have proposed another method of determining healthy intakes of n-6 and n-3. Studies show that the risk of coronary heart disease (CHD) is 87% lower in Japan than it is in the U.S, despite much higher rates of smoking and high blood pressure.

When researchers examined the concentration of n-3 fatty acids in the tissues of Japanese subjects, they found n-3 tissue compositions of approximately 60%. Further modeling of available data suggests that a 60% tissue concentration of n-3 fatty acid would protect 98.6% of the worldwide risk of cardiovascular mortality potentially attributable to n-3 deficiency.

Of course, as I’ve described above, the amount of n-3 needed to attain 60% tissue concentration is dependent upon the amount of n-6 in the diet. In the Phillipines, where n-6 intake is less than 1% of total calories, only 278mg/d of EPA & DHA (0.125% of calories) is needed to achieve 60% tissue concentration.

In the U.S., where n-6 intake is 9% of calories, a whopping 3.67g/d of EPA & DHA would be needed to achieve 60% tissue concentration. To put that in perspective, you’d have to eat 11 ounces of salmon or take 1 tablespoon (yuk!) of a high-potency fish oil every day to get that much EPA & DHA.

This amount could be reduced 10 times if intake of n-6 were limited to 2% of calories. At n-6 intake of 4% of calories, roughly 2g/d of EPA and DHA would be needed to achieve 60% tissue concentration.

The Omega-3 Index

Finally, Harris and von Schacky have proposed a method of determining healthy intakes called the omega-3 index. The omega-3 index measures red blood cell EPA and DHA as a percentage of total red blood cell fatty acids.

Values of >8% are associated with greater decreases in cardiovascular disease risk. (Note that n-6 intake was not considered in Harris and von Shacky’s analysis.) However, 60% tissue concentration of EPA & DHA in tissue is associated with an omega-3 index of between 12-15% in Japan, so that is the number we should likely be shooting for to achieve the greatest reduction in CVD mortality.

The omega-3 index is a relatively new test and is not commonly ordered by doctors. But if you want to get this test, you can order a finger stick testing kit from Dr. William Davis’ Track Your Plaque website here. It’ll cost you $150 bucks, though.

What does it all mean to you?

These targets for reducing n-6 and increasing n-3 may seem excessive to you, given current dietary intakes in the U.S.. Consider, however, that these targets may not be high enough. Morbidity and mortality rates for nearly all diseases are even lower for Iceland and Greenland, populations with greater intakes of EPA & DHA than in Japan.

All three methods of calculating healthy n-3 and n-6 intakes (targeting an n-6:n-3 ratio of 2.3:1, 60% EPA & DHA tissue concentration, or 12-15% omega-3 index) lead to the same conclusion: for most people, reducing n-6 intake and increasing EPA & DHA intake is necessary to achieved the desired result.

To summarize, for someone who eats approximately 2,000 calories a day, the proper n-6 to n-3 ratio could be achieved by:

  1. Making no changes to n-6 intake and increasing intake of EPA & DHA to 3.67g/d (11-oz. of oily fish every day!)
  2. Reducing n-6 intake to approximately 3% of calories, and following the current recommendation of consuming 0.65g/d (three 4-oz. portions of oily fish per week) of EPA & DHA.
  3. Limiting n-6 intake to less than 2% of calories, and consuming approximately 0.35g/d of EPA & DHA (two 4-oz. portions of oily fish per week).

Although option #1 yields 60% tissue concentration of EPA & DHA, I don’t recommend it as a strategy. All polyunsaturated fat, whether n-6 or n-3, is susceptible to oxidative damage. Oxidative damage is a risk factor for several modern diseases, including heart disease. Increasing n-3 intake while making no reduction in n-6 intake raises the total amount of polyunsaturated fat in the diet, thus increasing the risk of oxidative damage.

This is why the best approach is to limit n-6 intake as much as possible, ideally to less than 2% of calories, and moderately increase n-3 intake. 0.35g/d of DHA and EPA can easily be obtained by eating a 4 oz. portion of salmon twice a week.

Check out my Update on Omega-6 PUFAs here.

194 Comments

Join the conversation

  1. I’d like to know what Dan asked also, but I would also like to point out or ask I should say did you take into consideration with Avocados and Nuts, well because omega-6 linoleic acid from plants (such as avocado and nuts ) does not convert at a high rate to arachidonic acid (aka one of the bad guys) that is found in meats?

    Like for example pigs I have read converted linoleic acid to arachidonic acid for us, whereas the above is not the same case?

  2. Hi Chris,

    You calculated the content of half an avocado, some chicken and walnuts to 7.6% of energy intake. Did you take into account the omega 3 in these three foods?

    Thanks,
    Dan

  3. Dear Chris Kresser,

    Thanks a lot for your articles as I totally agree with you.
    But could you please write me in few words what is better to have and eat especially for woman because its very hard for me to understand totally what you are writing as my native lang is not english.

    • Chris,
      Yes plz, I’d like to see a chart of foods with omega 6 and with omega 3.
      I’d especially like to know: do certain foods contain both? What are they?

  4. Future tests will conclude that their previous conclusions were incorrect and you don’t actually need a “Maths Degree” to eat healthy.
    As for me, I plan to continue eating all whole foods in a balanced diet and let Mother Nature worry about the rest.

    • Kimberly
      I agree with your attitude of acceptance and trust in nature, but would add that your choices as a conscious being are part of nature too. For myself, and I suspect for many other people here, the main reason we need to do the “maths” is to defend ourselves from all the misinformation that plagues us and reaches into our pocketbooks at every opportunity.

      Someday you might find yourself with a “disease” that seriously effects the quality of your life but refuses to just kill you outright… even if you tried your best to “eat whole foods in a balanced diet.” Will you allow your trust or fatalism then to disempower you? Will you become passive, depressed, and suicidal as a non-participant in your own life… or will you do the math?

  5. Thanks for the article!

    Question:

    Does your body WEIGHT matter also in determining how much Omega-3 to take?

    I understand the Omega-6 intake is crucial, but how about your body weight? Should a person who is 132lbs take as much as someone who’s 264lbs? Is there something like a factor to multiply based on your body weight or similar…??

    Your help is much appreciated.

    Thank you!

    • It’s a possible step but not really much to talk about.
      “Conclusions: Substantial differences in intakes and in sources of n−3 PUFAs existed between the dietary-habit groups, but the differences in status were smaller than expected, possibly because the precursor-product ratio was greater in non-fish-eaters than in fish-eaters, potentially indicating increased estimated conversion of ALA. If intervention studies were to confirm these findings, it could have implications for fish requirements. ”

      Difference was smaller than expected but still “Substantial”

  6. There are far too many flaws in your recommendations in most of your articles (or at least in the many I’ve read). This one especially – the tiny amount of total fat intake your recommending is not enough for a healthy metabolism or necessary fat soluble vitamin absorption. Also walnuts have more omega 3 than 6, not to mention 100grams of which is a huge “handful”… I doubt you’ll even reply to this

  7. Hi,friends. Are 10grams per day (counting only epa plus dha) of fish-oils with vitamin E,safe to take with prozac sixty mgs daily? Many thanks. Best regards. Marcus

  8. Hi Chris,

    Thanks for all the education thus far. Quick question…

    What is your take on supplement Coenzyme Q10? Does it help the heart?

    Thx

    • Check with your doctor to see if you are sensitive to neuromins. They are an Omega 3 made from Algae. Best of luck.

  9. Chris,

    What about grass/insect fed pasture eggs vs farm eggs? The omega-6/omega-3 ratio for the two will be significantly different too right? Any article you can point me to?

    Ninad.

  10. zinzino’s balance product are the one you guys are searching for:
    http://www.youtube.com/watch?v=sf8xyd5be7M

    I can hook you up if interested, just sayin’.
    Best product in 2013, feel so fine after starting, and i can prove it to myself that its not something placebo feeling, by the test taken at the Norwegian Hospital: St.Olavs, that my balancerato omega 3:6.

    Thank you for now, and have a good year.

    Regards,
    Henning
    [email protected]

    • Henning N. Troe- I second that post. I’ve been taking balance oil from Zinzino and you are 100% correct!
      Visit balance321.com for more information.

  11. We fry with grapeseed, (small amounts) and use extra virgin olive oil for low and no heat dressing. We use butter for baking (rare) and sauces (occasional). We take three caps of cold pressed flax and wild salmon each daily plus sylimarin, turmeric, and ubiquinol. We also never have wine without cheese (drunken mouse diet ;>P )
    Our question: is any component lethal or severely deleterious? Thanks
    PS great detailed examination of fats in diet!

  12. I’m referring to this article’s recommendations. I agree with what you say. I’ve read that 4:1 is a good ratio and this is what I currently consume. But this article says the optimal is 2.3:1 or less. On the other hand I see by calculating the recommended omega 3 amounts (pasted below) that are based on a 12.6:1 ratio if I’m not wrong!

    “To summarize, for someone who eats approximately 2,000 calories a day, the proper n-6 to n-3 ratio could be achieved by:

    Limiting n-6 intake to less than 2% of calories, and consuming approximately 0.35g/d of EPA & DHA (two 4-oz. portions of oily fish per week).”

  13. 2% of Omega 6 intake in a 2000 calories diet is 40 calories. 40/9 (fat calories) is 4.4 grams of omega 6. The recommended Omega 3 is 0.35 grams. So we have a ratio of 4.4 : 0.35 (12.6 : 1). I thought that the optimal ratio is below 2.3 : 1. Could you please help me understand this? Thank you.

    • Are you sure you didn’t mean 3500mg or 3.5g? 900mg is what most health authority institutions recommend as a daily minimum. Omega-6 is very hard to avoid — it is even in fish oil. Eating nothing but saturated fat and fatty fish / fish oil within the context of a safe carb diet is the only way to minimize Omega-6 intake.

  14. I have to eat 20% fat from my total 2600 calories. How can I limit my Omega 6 intake to 2%? It seems impossible!

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