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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. I remember a teacher telling me about studies about toxicity (probably only specific toxins, but I forget which ones) in fish being exceptionally bad where I live, New Brunswick Canada. (Of course, we also have a massive cancer rate which is currently being studied, they think it’s the arsenic in the soil…damned no matter what I eat!) Anyways, is there more of a concern for eating too much seafood depending on where it’s caught? Why is farmed fish worse for toxins? Wouldn’t it be better seeing as where it’s farmed, especially if in a man-made area separate from regular waterways, there’s virtually no worry of the dumping of toxins into the water?

    More on topic, I see that eggs are pretty high in omega 6. But currently I usually buy the free range, omega 3 eggs from a local farmer. How much extra omega 3 is in these eggs? Is it enough to perhaps counter unhealthy levels of omega 6? Is it even in a proper form for people to digest, seeing as it’s originally from flax? I certainly notice a taste difference, and I can’t say I like the fishiness, but I buy them because they’re a good price for eggs that I feel are ethical to the chickens.
    And what about organic eggs? Everywhere online says organic eggs aren’t any better health-wise than regular, battery eggs, but organic chickens would eat a lot of grubs and not so much grain, right? If there’s a noticeable difference in grass-fed vs grain-fed cows, and if a chicken’s diet of flaxmeal can create omega 3 eggs, it seems likely the nutritional content would change if they’re eating bugs…

  2. Hi Chris,

    Thanks for your work. I have read a few of your articles re: omega 3&6 including this one and aren’t seen Chia seeds mentioned. I would rather get my fatty acids from whole foods rather than taking a supplement but I have yet to acquire a taste for sardines (if you know of a palatable way of taking them, please share!) I have heard that Chia seeds have a favorable FA profile but am having a difficult time confirming this. What are your thoughts?

  3. Hi, Great article.
    Obviously I understand eating fish is best but ive always also supplmemented with a good source fish oil (nordic naturals) I did take the omega 3 one but then switched to an omega 3/6 balance thinking it was best. I have hasimotos. Now im thinking prob best to stick with supplmenting just omega 3 again, whilst trying to eat balanced and healthy too? I have a lot of olive oil so im prob getting too much omega 6 already so adding it in a supplement perhaps not a good idea? Thanks Carly

  4. Chris, if you consider walnuts to be okay, what about the oil made from it or sees like sesame? I do like a drizzle added to a stir gry or salad…!

    Cheers

  5. I am glad you did change your view Chris, because most studies that found omega 6 are harmfull, are done with damaged omega 6, which are added to various foods, spreads etc. These omega 6 are heated , partially hydrogenized, so no wonder their consumption is associated is with diseases. However, omega 6 in their natural state most often are found beneficial. e.g. look at the studies with nuts , almost every study finds benefits of nut consumption, and most nuts are much higher in omega 6 than omega 3.

    And I am afraid the same is with the fructose, people see studies with purified or HFCS and then start telling not to eat even fruits.

  6. Chris–great article (and love your site).

    I noticed the mention of Walnuts in your article as being high in n-6. Unrelated, I recently read the study in the american journal of cardiology which found that the addition of daily walnuts to meals increased artery flexibility by 24%.

    Weighing the arterial benefits against the n-6 downside, what is your general feeling on daily walnuts?

    • I’ve changed my view somewhat on omega-6 from natural sources since writing this article. I think it’s somewhat unlikely that n-6 from walnuts would cause harm, and of course nuts and seeds have health benefits as you pointed out. Walnuts are also quite high in n-3, which probably explains their effect on arterial flexibility.

    • Yes, there is quite a bit of conflicting research on the n-6:n-3 ratio. I may need to revise this article based on what I’ve been reading lately, but the jury is still out.

  7. Hi Chris,
    Was wondering if you had heard of sacha inchi oil and what you thought of it…I have been supplementing with it because you can get 10 grams of omega 3 in 1 tsp a day.
    Thanks

  8. a full and supervised elimination diet is what you need to do, anything less will only keep you as sick as you are now. You cannot just reduce gluten and lactose… you need to eliminate them completely. Suppose you are casein intol, how will you know unless you give up all dairy?

    I speak from experience having been down a similar road like you.

    • justmeint, thanks for your reply. i have completely cut down gluten and lactose from my diet.
      chris, would appreciate your thoughts and links for me to follow pls. i have read all the hashimoto link of yours it was very helpful for me. thank you so much chris to give in detail the information.

  9. chris,
    I am 31 and suffer from hashimoto thryroditis but my T3 T4 TSH reports are normal and i am taking the synthroid 25 mg. I have a nodule present in the left. I have gastritis, heaviness in left abdomen after eating food,
    disturbed sleep, burning sensation on the left side of neck area after eating some kind of food and left knee throbbing in the night and pulse in the nodule which wakes me up..no idea when and what food triggers.. tired of noting down the food diary is exhausted now. Difficulty in conceiving. My left side remains inflammed. Have cut down gluten and lactose for last 4 months. the abdomen symptoms have reduced lot like the bloating and gas. but inflammation in the neck remains. have been following and avoiding all goitregenic foods. can you suggest what is the main culprit behind all this problem. what type of oil i should use for cooking. at present i use canola and olive oil. pls provide some dietary guideliness which will help me.

    • Rati, the main culprit behind your problem is bacteria. So here’s your best solution: Astragalus, Pau D’Arco, Artichoke Extract, Oregano Oil, Mastic gum, Pure Cranberry Juice, Cranberry tea, Vitamin A, Chickweed, Milk Thistle/Dandelion, and Align. Through no fault of your own, your immune system is lopsided, and it is constantly fighting the craftier, BAD bacteria that dominates. You basically have a systemic bacterial infection. Your not alone on this. There’s millions of us with this problem and the principal symptom is inflammation. Everything that I put in that arsenal of herbs, vitamins, and pro-biotics fights bacteria. Not permanently, but you can repeatedly create an opportunity for your body to push back and allow for the proper absorption of nutrients and the utilization of the Omega 3’s by taking them throughout the day. Before bed, Astragalus, Pau D’Arco, Artichoke Extract, Oregano Oil, Chickweed and Vitamin A and you’ll be able to sleep. We need greater amounts of Omega 3’s and Vitamin A when our body is fighting a systemic infection. In particular, Vitamin A which can get devoured very quickly by too much Vitamin D, found in fish, so be aware of that. Very important, otherwise you’ll be affected by depression and get overall poor results. I don’t believe doctors have even begun to understand this problem with bacteria. You should research “Quorum Sensing.” It’s quite eye-opening to discover that bacteria can behave like a communicating flash mob. Of course, you still have to keep the Omega 6’s at a bare minimum because, until science figures out a way to permanently fortify our immune systems, the bacteria isn’t going anywhere. It’s a part of us. You have to become your own external immune system, so to speak, and help your internal immune system to constantly beat back the BAD bacteria because it simply can’t do it on its own. This is why many of us are spinning our wheels. Don’t fret, the depression and the fog will lift with just the first round of this protocol and you will realize the healthy body that you thought was gone is still there. Just be smart. Don’t get sloppy with your diet when you start feeling better because that bacteria will come back fast and furious. Really fast. Then the fog and depression will come back and you’ll have to dig yourself out again. P.S. That thyroid problem of yours is being caused by bacteria too.

  10. Chris,
    Excellent articles on fish oils and the omega 3 supplementation, but you left out the problems with increased strokes and colon cancer at high dose levels. In studies of two populations, South Pacific Islanders and Aleutian natives, who had diets with high levels of raw fish, heart disease was dramatically reduced but they had five times the incidence of stokes and colon cancer. Those results were collaborated in clinical studies with pigs at Vanderbilt in the mid-1990s.

    Also, it would help if you would specify which essential fatty acids you (and the researchers) are calling omega 6 fatty acids. Some of the omega 6 fatty acids also make PGE1 which is a powerful ANTI-inflammatory prostaglandin.
    In fact, like the delta-6-desaturase, the delta-5-desaturase is easily blocked by EPA, caffeine, tobacco, alcohol, stress, age, etc. so that further favors the formation of the powerful anti-inflammatory PGE1 from DGLA.
    If you want to suppliment with Evening Primrose Oil (EPO) to enhance GLA/DGLA be sure that you use a supplement with real EPO (like Efamol) instead of diluted black currant oil or borage…those oils do not demonstrate benefits in clinical studies.

    The Best,

    Bob Deschner

  11. at a GP visit yeaterday she told me she had recently attended a conference where it was told that certain patients should limit their intake of fish oil capsules to 1000mg per day. the reason this came up – I have a bleed behind one eye….. she asked how much supplemental fish oil I was taking, and the told me to reduce it to 1000mg per day because I maybe a sussceptible (?sp) bleeder.

    I have stents in and refuse statins. I take the fish oil as an anti inflam medication inseat of the statins….

    Would appreciate your thoughts and any links for me to follow please

    • Most studies I’ve seen suggest that fish oil doesn’t cause or worsen bleeding even at fairly high doses.

  12. Thanks for the informative series. I’ve been working on changes to reflect the info here. I have a question. If it has already been answered, please forgive me and point me to the right place.

    I was wondering about ALA. In the example you provided, you say,”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.”

    How do you maintain ALA at about 2.35g/d, especially if you reduce LA sources likes nuts and seeds? I tend to eat mostly meats, eggs, raw dairy, veggies (including roots/tubers), some fruit, and limited amounts of nuts/grains/legumes. I have recently started to add 2-3 servings of fish a week (mostly salmon, halibut, and ecofish tuna).

    • You don’t have to worry too much about ALA. Just increase fish intake to 3 servings per week (6-7 oz. each) and reduce LA and that will do it.

      • Thanks. That makes total sense. I’m still wrapping my head around eating fish 3x/week (4oz each), so I think I was worried about bumping it up even more (I cut fish from my diet 5 years ago when I was pregnant due to mercury concerns. Ack.) My family is from coastal Ecuador, so fish was a huge part of my diet when I was younger. Nice to know about selenium’s affinity for mercury.

  13. …And one follow up question: I feel like I have seen a lot of claims that scientific studies found many health benefits of nut-consumption. Sorry I’m so obsessed with nuts.

    Thanks!
    Max

  14. Hello and thanks for al the great information!

    I was wondering if you would have different recommendations for a competitive endurance athlete (x-c skiing) training multiple times per day. Does this change anything concerning limits on omega-6 consumption? I eat very close to your recommendations except that it is hard to get enough energy so I like to eat a lot of nuts. I am 22 and generally fit and healthy though I have some trouble with eczema.

    Thanks!
    Max

  15. Hi Chris,

    I heard you briefly mention borage oil once on your podcast. My integrative doctor has me take 1,000 mg twice a day. She did a functional test which tested all of my levels. My omega 3s were great, but I have low levels of DGLA and GLA. Is that something to be concerned about? Isn’t it better to have more omega 3?

    What are your thoughts on borage oil? My omega 6 level overall is pretty low. (no seed oils, nuts etc)
    Amanda

  16. I avoid all seed oils and nuts except macadamia nuts, and I usually eat canned sardines or wild caught salmon four to five times a week, is this going to be too much EPA in light of what Chris Masterjohn has said: “Providing high doses of EPA that interfere with arachidonic acid metabolism, however, is a pharmacological approach, and it is likely to have many adverse consequences.”

  17. OK, I assume you mean Cod Liver Oil, which is rich in Omega-3s (also A and D).

    It is hard to find doctors who listen to their patients, or listen to anything other than what they remembered from medical school. Harder still to find good doctors who take insurance, especially things like Medicare and Medicaid. If you find a good doctor, you will also be dealing with his (or her) pet theories. None of the “alternative medicine” concepts have been rigorously tested (except with the intent to discredit them), and so you will always have trouble getting the right balance for you. Western medicine has never been interested in the individual, only in general treatments (and promoting those treatments as much more universal than they are).

    OK, now that I’ve dug myself into that hole, I hope you will reject the partial thyroidectomy — that makes as much sense as “curing” mental illness with a lobotomy (or electro-convulsive “therapy”). I would suggest you consider lithium orotate — it’s cheap, readily available, and safe. (The only research showing it to be unsafe used thousands of times per body weight over suggested amounts, proving only that minerals are toxic when taken at toxic levels.) I can’t show you any research on lithium (at proper levels) and thyroid, but have several members of my ALT-therpaies4bipolar group who have greatly reduced or eliminated their thyroid meds, often with concurrence from their doctor.

    But this is Chris’ group, and I have no intention of taking over either the group or the conversation. Feel free to contact me off-list, or just think about what I’ve said and accept or reject it as you will.

  18. ahhhhh the other oil I forgot to mention that I consume daily is CLO. Doc said my D levels were fine, so I decided to take a daily CLO capsule to keep them that way. I am photosensitive, so do not spend much time out in the sun, it causes me that wretched butterfly rash on my face.

    NO I have not been prescribed any prescription thyroid meds….. only suggested I take selinium which I had to find without brewers yeast (not suitable for my diet) and aswaganda (?sp) to perhaps help my thyroid and won’t hurt my other autoimmune issues. I am diagnosed SLE with vasculitis.

    Doc is considering a partial thyroidectomy….. I want more information first and a closer look at what my alternatives may well be. I have found this site very informative and helpful. Gut issues do so much damage to the entire body and yet I have not found a GP yet who appreciates that fact.

    Cheer’s

    It is important to me that I provide the right balance of ‘ingredients’ for my system. I work hard at that.

  19. I’ve heard a lot of negative stuff about krill oil… the only positive info comes from Dr. Mercola, who owns most of the company. How much fish are you eating? Three servings per week of dark muscle meat fish are said to be sufficient. But nothing else you are eating has any Omega-3s in it. The nuts are mostly 6 and 9.

    You don’t talk about medications you may be taking… there are a lot of things you can do for the thyroid issues, but the best (and least known) may be lithium orotate. The low levels of lithium in this product appear to be ideal for thyroid issues. Most people see lithium as being damaging to the thyroid, but that is in the light of the toxic levels of lithium carbonate given to many people. Lithium orotate is available over the counter if you can find it, and over the Internet.

    And now we are officially off topic. LOL Hope it helps anyhow.