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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.

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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.

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194 Comments

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  1. Dear Chris

    Some questions regarding cooking with vegetable oil. I saw in the diagram provided that Palm oil or Palm Kernel Oil where significantly lower in N-6 acids than the majority of vegetable oils, even lower than olive oil and only superceded by Coconut oil. Where I live, in Thailand the least expensive vegetable oil is Palm Oil from Pericarp. For cooking purposes, would you suggest choosing Palm Oil from Pericarp as a healthier alternative than other vegetable oils like ricebran, canola or sunflower oils as the N-6 content is lower.

    Do you know of any other drawbacks to health ingesting palm oil? It would make sense using palm oil for cooking as it is the less expensive than for example rice bran, canola or sunflower and at the same time according to the charts contain lesser N-6 acids.

    With best regards, Stefan Stolt

  2. All super interesting information.
    Why, on most websites/blogs where the Omega 3/6 ratio is discussed, very few are talking about the Omega 3 rich vegetables that have low Omega 6, and that if you eat a diet rich in veggies and moderate fats and oils, that you are likely getting a healthy ratio? I read so many of these sites, and now on Paleo sites, and this vegetable portion seems to be ignored.

  3. According to the Nutrition and Food Information Center, the daily recommended intake for omega-3 for example for a 45 year old male is 1.6 grams a day, and it is 17 grams a day for omega-6. This gives us a ratio of omega-6 : omega-3 over 10:1. If we want to satisfy this requirement and also satisfy the ratio of 1:1, then a 45 year old male need to take 17 grams of omega-6 and also 17 grams of omega-3 daily (assuming he’s on a 2000 calorie a day diet)

    However I see, you are recommending to lower the omega-6 intake as much as possible, in order to satisfy the ideal ratio. I wonder if you could please explain this in more detail. In other words, is it okay to ignore that 17 grams daily omega-6 requirement? I am a fruitarian, and my omega-6 consumption is close to zero, and the ratio of 1:1 easily is satisfied. Would that be OK, or is there a certain minimum requirement for omega-6 and omega-3 besides the ratio? I appreciate your response in advance.

    • I believe you will find the 17g LA DRI being considered essential from the IOM is flawed, as only AA is actually essential, but not all LA is converted into AA. Similarly with ALA & DHA.

      Also, a 2011 review published in Nutrition & Metabolism entitled “Increasing dietary linoleic acid does not increase tissue arachidonic acid content in adults consuming Western-type diets: a systematic review”, concluded that there is “no evidence to suggest that changes in dietary linoleic will modify tissue arachidonic acid content in an adult population consuming a Western-type diet.”

  4. Hello Chris,
    Great information. dicussion and site. I’m following this thread closely as I have active Ovarian Cancer, Autoimmune Diabetes Type 1 and Hashimoto’s. I used to used olive oil, now most of my oil consumption, cooking etc., is coconut. I have had liver pain, likely inflammation, from lots of meds used to battle diseases, (both traditional and alternative meds.) I just began taking Nigella Sativa oil and am concerned about dosages. It is reputed to have anti-inflammatory impacts internally, and ingredients that help some cancers, especially pancreatic. It is roughly 25% omega-9, 46% omega-6 and .5% omega-3 in composition. Probably I am safe taking 1 tblsp. per day. I would like to gain from its anti-cancer and anti-inflamm properties w/out OD’ing on the omega-6’s. When I take this oil, my liver pain decreases significantly. It seems that I should be OK if I up my cold water fish intake to 2 or 3 4 oz. servings per week to offset the omega-6 consumption. I think the Nigella Sativa oil is by far my most significant source of omega-6’s. I don’t eat that many eggs or that much chicken. Glad to hear that the jury is reconsidering how much is too much omega-6! Any thoughts, comments or suggestions from you, Chris, or readers of this site would be most welcome! Thank you!

  5. Awesome post. Thank you for taking the time to write this out.

    Question: does it matter how the fish oil doses are divided? For example, if I had an aversion to fish, and wanted to replace 16 oz of salmon per week with Vital Choice brand, is there any benefit/disadvantage to taking fish oil 2x per week vs. taking fish oil every day?

    When I looked over the nutritional info on Vital Choice’s salmon oil, 3 caps = 600 mg of o3. Nutritiondata says that 1 oz of salmon has 600 mg o3. It works out to 48 fish oil caps from VC, 24, 2x a week or 6 per day. Either way it’s a lot of fish pills, but about the only way I can stomach fish (plus, I discovered VC has a lot of Vit A and D which is good since liver is another weak link for me).

    Thoughts?

  6. Chris, I’m just exploring your site for the first time and I’m wondering why no one suggests replacing these vegetable based cooking oils with something as simple as lard? You can get inexpensive skin and fat from pigs that were *actually* raised free-range on pasture, and render it yourself very easily. It won’t give you the omega 3/6 profile of fish, but is probably far better than anything plant-based.

  7. I am eating an 80-10-10 vegan diet and tracking my nutrition with a computer program called Chronometer. On the diet I meet or exceed all nutritional requirements except Omega 6. The targets for omega 6 = 17g. (I’m 46 years old) and omega 3 = 1.6g. seem impossible to attain without adding oils to meals. My situation is unusual because I get 1.0g. ALA and 3.6g. LA in my daily diet. When I add 2g. of cold pressed flax oil to my salad in the evening, the numbers change to ALA 2.0 & LA 3.9. The ratio is excellent (1.922:1) but the amount of LA is far from what is recommended. Is the diet safe with LA so low? Does my body need all of that LA or are the numbers set high to deal with the typical American diet? I hope it’s safe to eat this way ’cause i’ve never felt better.

  8. Hi Chris,

    I wondered if you could help me with a question about Omega 3 and Omega 6 balance?

    According to the USDA, I should aim for at least 17g of Omega 6 a day. Therefore, to get the 1:1 ratio with Omega 3, I need to eat something like 1.5 kilograms (over 3 pounds) of salmon A DAY.

    Are you suggesting I eat all that fish, or is the Omega 6 requirement off?

  9. Actually, the optimal ratio of omega 6 and omega 3 essential fats is more dependent on the types or form (natural cis- or artificial trans-) of the omega 6 fatty acids. Type refers to whether the n-6 essential fatty acid is arachidonic acid which is converted to prostaglandin PG E2 (an inflammatory PG); higher up on the metabolic chain such as linoleic acid (LA) (which is easily blocked by n-3 fats); or gamma-linolenic acid (GLA) which is converted 20%/80% to the highly anti-inflammatory PGE1 and inflammatory PGE2).

    The n-3 essential fatty acids can do more harm acting as metabolic blockers of n-6 metabolism then any competitive absorption issue between n-6 and n-3. Furthermore, recommending eating fish without specifying the type and quality of fish (deep ocean cold saltwater fish is much better than others, especially farm-raised); how to avoid toxicity from heavy metals and oil soluble pesticides and excess vitamin A/D; and preparetion of the fish (frying or cooking fish at high temperatures causes the formation of trans-fats which are metabolic poisons) is naïve if not unhealthy.

    Please point out that most of the US studies which have been conducted blindly lumping all omega-6 fatty acids (both inflammatory and anti-inflammatory) into the same bucket and totally ignored the cis- / trans- ratio of the essential fats—therefore these studies are not worth the electrons which are used to store them.

    If you would please go back to the original literature—metabolic and clinical studies which first elucidated the essential fatty acid/prostaglandin metabolism—you will find much higher quality studies, more sophisticated analyses and better understanding of what is actually happening.

    The Best,

    Bob Deschner

  10. Dear Chris,

    the frozen wild salmon (Northwest Pacific) I’m able to get (here in Germany) contains 10,5g (0,37oz.) of fat in 100g (3,5oz.), of which 2,5g (0,088oz.) are saturated. Now I don’t have any idea how much Omega 3 I am getting there (it’s not listed).

    You said that 12-18oz. of fish a week are fine, but I was wondering how that would translate with these values. If I may ask, how high is the fat content in the wild salmon you recommend?

    Another brand for instance, only lists 2g fat (0,07oz.) in 100g (3,5oz.) of their wild salmon.

    How much fat in total should these servings you recommended contain? I’m not sure how to translate this to the 0.65g/day of EPA/DHA you specified.

    Thank you so much
    Chris

  11. Hi, I too am a fan of chia seeds. I’ve noticed that my hair and nails are stronger and grow faster. Also, they help me stay hydrated and alcohol intake has little or no effect on me the next day. They are also a fantastic source of fiber. Pls, Chris, address the Chia question above when you get a chance. Thank you!

  12. In your previous article, you discussed the low conversion of ALA to DHA/EPA. But, in this article you take full credit for ALA in determining the O6/O3 ratio. In your example, you add 2.35 g/d ALA to .65 g/d DHA/EPA to get a 2.3/1 ratio based on 7 g/d O6. If I am consuming 7 g/d O6, why wouldn’t I want to consume (via fish or fish oil capsules) 3 g/d DHA/EPA? Unless I am consuming large quantities of flax, seems like I should ignore dietary ALA. Thanks.

  13. When I eat only fruit and veg , my omega 6:3 ration is usually around 1:1. On these days get around 1 g of omega 3, at least cronometer says so.

  14. Hey Chris,
    You said that many vegetarians and vegans have low EPA and DHA intakes due to poor conversion from plant-based sources. However, they also probably have low Omega-6 in their diets (assuming they don’t eat a lot of omega-6 nuts), so the ratio is probably close to ideal, right? Is there a minimum amount of polyunsaturates you need, and is the 4% of total calories a good estimate? What do you say the average intake of polyunsaturates is in disease free civilizations (i’m curious to the quantity consumed by those who do not typically live near coastal areas).
    Thanks!

  15. Yes, it’s better than flax. Flax (or hemp seed oil) has ALA, which slowly, inefficiently can be converted to DHA or EPA. There is still some question which of the long-chain n-3s is more important — Chris leans to DHA. The algae supplement is already DHA. No, I haven’t tried it, as I do find with regular fish oil, but I get asked this question a lot.

  16. Help !! I’m vegan and do not eat fish. How can I best reverse the n-6 : n-3 ratio in my diet back to optimum levels?

    • The only option you have to increase your DHA levels is algae. I think Dr. Furhman sells some. This is one of many reasons why a vegan diet is not optimal.

    • I’m eating a vegan diet too and according to my logs I easily achieve a n-6 of under 2% of my calories. The n-3 part comes easily too but I guess I’ve got to depend on my body to convert that into EPA and DHA. So hopefully with such small amounts to work with my body can get er done.

      • The best way to find out is an omega-3 index test. You can order directly from OmegaQuant. I have no relationship with them, but Dr. Bill Harris who has done a lot of research on EFAs is behind that lab.

  17. Err, proper form to ‘digest’ isn’t right, is it? Basically is the omega 3 in those eggs going to be useful or not useful.