Fish oil versus flaxseed oil

Since we started practicing nutrition-based medicine 20 years or so ago we have been advocates of fish oil. The modern diet of today simply doesn’t provide enough of the omega-3 long-chain polyunsaturated fats (LCPUFA) that we need for optimal health. In Paleolithic days early humans probably got as much omega-3 fats as we did the more inflammatory omega-6 fats; today the standard American diet, thanks to the addition of vegetable oils, provides about 10-20 times more omega-6 than omega-3. We advise our patients to both avoid the high omega-6 fatty acid vegetable oils and take fish oil to increase omega-3 fats.

We are always asked our opinion of flaxseed oil as a source of good omega-3 fatty acids. We always respond that it is okay, but that taking fish oil is a much better way to increase the levels of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), the LCPUFA that we really need.

Flaxseed oil has high levels of alpha-linolenic acid (ALA), an omega-3 fat. When consumed ALA enters the fatty acid pipeline and is desaturated and elongated by the appropriate enzymes until it is partially converted to EPA then to DHA. So flaxseed oil does increase the levels of EPA and DHA, but, we think, not nearly as much as does fish oil, which already contains the preformed EPA and DHA we need.

Over the years we’ve taken a lot of flack (flax?) from various people and companies that sell flax oil. We’ve been inundated with testimonials from people who have been healed of—it seems—every disease known to man simply by taking flax oil. I don’t know why, but it seems that flaxseed oil lovers have an almost religious affinity for the stuff. Despite it all, we’ve hung tough and stuck with out recommendations for fish oil instead of flaxseed oil simply because a) it makes more sense biochemically, and b) our patients seemed to do better on fish oil.

A recent paper from the British cardiology journal Atherosclerosis bears us out.

Subjects who had fish oil added to their high omega-6 diet had much higher levels of EPA and DHA in their cell membranes after a few weeks of supplementation than did those who had added flaxseed oil. The study showed that in all lipid parameters evaluated the fish oil won out handily over the flaxseed oil. Those taking fish oil had lower levels of small dense LDL, lower levels of triglycerides, and higher levels of HDL. All this lipid lowering is fine and dandy, but since the whole idea that lipids are somehow involved in the development of cardiovascular disease is hypothetical at best, I don’t know how much importance I would attach to the lipid findings.

The critical factor is the increased levels of LCPUFA in the cell membrane. Elevated levels of LCPUFA do many good things, chief among them is protecting against cardiac arrhythmias. Heart disease is the number one killer of people in America and one third of all heart attacks have sudden death as their first symptom. That means just what it says. The very first symptom one third of the people who have a heart attack experience is sudden death, a symptom it’s difficult to recover from.

What happens is this: a blockage in the coronary artery (arteries) reduces blood flow to an area of the heart. If the area with the reduced or absent blood flow contains conductive fibers critical to the transmission of the electrical impulse that triggers the coordinated, rhythmic pumping of the heart, these fibers may be compromised and cut off the conduction of the impulse or they may conduct it aberrantly. If the impulse stops, so does the heart. When the heart stops for any length of time, so do you. LCPUFA stabilize the membranes so that they are not so prone to malfunction in the presence of lowered oxygen levels.

For my money, I would much rather have my membranes protected by the much higher levels of LCPUFA found in fish oil.

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10 thoughts on “Fish oil versus flaxseed oil

  1. Dr Mike – Thanks for this post. It capsulizes what I’ve been trying to get a friend with rheumatoid arthritis to take now for some time.
    I hope this comment ‘flies’; It’s my 3rd attempt. Twice before my comments to your 9/13/06, and 9/19/06 posts, upon the decode and ‘submit’ click! just vaporized? They were on ‘IF’; I’m 72, in week 2 of getting down to my high school 175lbs. (6′ even, was 6′- 2″ even, then!), 25 to go after 260 to a 200 lb plateau for several years, using ‘low carb’, to get there. – Jim C.

    Hi Jim–

    Sorry about all the trouble you’ve had getting your comments through. Thanks for being persistent. I would suggest that your friend try the krill oil regimen (krill oil, fish oil, circumin) that I wrote about a couple of months ago.  It may take a couple of weeks before real benefit is seen, but most people have reported terrific results.

    I’m glad to hear the IF is going so well for you.  How much weight have you lost since you started?

    Thanks again for keeping on trying to get through.  I think we’ve got most of the bugs worked out.  Keep your fingers crossed.

    Cheers–

    MRE

  2. Dr. Mike –

    How would you interpret the findings (here, here, here) that strongly link the level of saturation of cell-membrane omega-3 phospholipids (ie short-chain ALA) to maximum lifespan in various vertebrates? The reasoning goes that while more carbon-carbon bonds in a lipid gives it more versatility, it also increases (exponentially, apparently) the lipid’s risk of peroxidation by free radicals, meaning that a high ratio of EPA and DHA in the body will grease it up and get it running fast, sure, but will also quickly speed up the aging process as well and potentially cause all sorts of deleterious diseases in the long run.

    There seems to be a law of diminishing returns for added double-bonds in a lipid (since subsequent bonds are placed closer to the ends of the chain which contribute less to its overall “flexibility”) and also an exponentially increased risk of oxidation as well. It would also seem that the organ in the body most needful of quick-acting DHA, the brain, is insensitive to dietary DHA as far as its composition is concerned.

    It seems to be that EPA and DHA are being recommended based on the findings of scads of very short-term studies that find immediate, fast-acting results – which is great, but might not reflect the increased long-term dangers inherent in longer-chain PUFAs.

    I know there are a lot of strange variables here – exercise is known to increase DHA levels in the muscle, which seems to make little sense since exercise is well-known to improve quality and length of life. And of course long-lived cultures seem to have a track history of high fish consumption, but then again there are no societies I know of that have a history of high flax/ALA consumption either, so a comparison between lifelong ALA and LCPUFAs and life span/quality really can’t be made there as far as I can tell.

    Based on all this, it would seem prudent to take flax instead. Increased benefits of fish oil over flax seem (or should be, theoretically) minimal, especially compared to the increased risk of peroxidation involved. There’s such a craze over fish oil that I haven’t found very many studies that directly compare LCPUFAs to SCPUFAs; most of them just compare the LCPUFAs to omega-6s and call the former the victors.

    Thoughts? This is a strange topic with conflicting evidence from my point of view, and I’d like to hear any clarifications you might have.

    -G Goodrich

    Hi Glen–

    I’ve read all the papers you referenced along with a lot of others on the topic. I love all the papers by Pamplona and Barja; they are doing a lot of interesting research. The paper by Hulbert is a classic.  I’ve thought about the information in these, and other, papers for a long time and haven’t really come to a complete conclusion.  But, I do have some thoughts.

    First, (and I’m not going to quote from specific papers right now because I don’t have them in front of me–this response is based on memory, which is always dangerous) it’s apparent that the unsaturation index can be lowered by consuming more saturated fats (by that I don’t necessarily mean saturated fats, but fats that are less unsaturated).  A lowered unsaturation index means that the fat acids (primarily in the cell and mitochondrial membranes) are less prone to peroxidation.  Less prone to peroxidation means longer lived.

    Evidence shows that dietary restriction reduces the unsaturation index, making the membranes less prone to peroxidation, meaning that (probably) a reduced unsaturation index does indeed lead to greater longevity.

    A couple of papers I’ve come across seem to indicate that insulin increases the activity of desaturation enzymes, meaning that elevated insulin levels would lead to more desaturation, i.e. fats that are more unsaturated, and, consequently, a higher unsaturation index.  If a lower unsaturation index leads to a longer life, one would assume that a higher unsaturation index would imply membranes more susceptible to peroxidation and a shorter life.

    ALA (again, according to a lot of reading I’ve done) is burned preferentially as a fuel source instead of being incorporated into membranes or shunted down the elongase-desaturase pathway.  ALA is also converted to ketone bodies easily because of its propensity for being rapidly oxidized.

    The sum total of these sort of random thoughts is that (to me, at least) the amounts of EPA/DHA consumed as fish oil are minuscule in terms of overall fat consumption and are (in my opinion) not major players in establishing the unsaturation index.  Consuming more saturated fats while keeping insulin levels low will maximally decrease the unsaturation index (but not to the point where membrane rigidity becomes a problem), providing membranes much less prone to free radical attack, and, consequently, increase longevity.  And since ALA doesn’t really enter the pipeline much to speak of, I’ve never considered it as a replacement for fish oil.

    I don’t know if this answers your question or not, but it’s the best I can do on short notice.

    Cheers–

    MRE

  3. Cordain strongly recommends eating fish/fish oil, so I wonder about his rationale for also recommending using flax oil in salads and rubbed on meats after cooking.

    Hi athelstan–

    I haven’t a clue.

    MRE

  4. Hi, What about people allergic to fish? Will taking flaxseed oil help or is there another way to get our omega’s?
    Help!

    Hi Laura–

    Flaxseed oil will help if that’s the only omega-3 source available because of allergy.  (I’ll admit that I’ve never seen someone who is allergic to fish across the board, though.)

    Flaxseed oil helps in another way besides providing omega-3 fats, which it doesn’t really do all that well.  Flaxseed oil is preferentially converted to ketone bodies, which are also good for one’s health.  So, you get a little of the good omega-3’s and a lot of ketone bodies.

    Cheers–

    MRE 

  5. I TAKE 2 CAPSULES OF KYOLIC GARLIC SUPPLEMENTS WITH ENZYMATIC AND IMMUNE FORMULAS, PER DAY. ALSO, 1 CAP. OF 500MG. ESTER-C/W BIOFLAVANOIDS & GRAPESEED EXTRACT,IN CAP, PLUS 25000 UNIT OF BETA CAROTENE IN A GELCAP. WOULD ADDING 1 GELCAP OF 1000MG OF FISH OIL BE TOO MUCH? I AM 63, AND HAVE SEVERAL MEDICAL PROBLEMS.A GENETIC CONDITION CALLED LYMPHEDEMA OF THE LOWER EXTREMETIES,(FOR WHICH I HAVE BEEN RECEIVING TREATMENTS)HYPERPLASIA OF THE UTEROUS(ALSO, RECEIVING NATURAL HORMONE TREATMENTS ) AND INCONTINENCE, (STILL TRYING TO FIND HELP WITH)ALSO, OBESITY, SUPPOSEDLY PARTIALLY ATTRIBUTED TO HIGH ESTROGEN,CONSIDERED POST MENOPAUSAL, FOR WHICH I AM PRESCRIBED, 10MG OF PROGESTERONE CREAM 2X A DAY I TAKE THE SUPPLEMENTS TO TRY AND REDUCE MY CHANCE OF DEVELOPING CANCER,BLOOD CLOTS, AND REDUCTION OF HIGH CHOLESTEROL AND TRIGLYCERIDES. DO YOU THINK I CAN ADD A 1000 MG. FISH OIL TO MY REGIMEN, OR IS THAT TOO MUCH, OR WOULD THAT BE IN CONFLICT WITH ANY OF THE ABOVE SUPPLEMENTS.? I AM INTERESTED IN THE FISH OIL DUE TO SOME EYE PROBLEMS.DRY EYE, AND BLURRINESS,– EVEN WITH MY GLASSES. YOUR PROFESSIONAL INPUT WOULD BE GREATLY APPRECIATED.

    Hi Barbara–

    I can’t give specific medical advice over the internet to patients I’ve never examined.  But, I don’t see any reason anyone can’t take 1000 mg of fish oil unless that person doesn’t have physician approval for such due to specific conditions I’m not aware of.

    Cheers–

    MRE 

  6. Hi – after much reading about flaxseed/oil and fish oil, I want to take both. I really could use the fiber available in the flaxseed. Would both be too much of a good thing?

    Lil

    I don’t think they would be too much.  Flaxseed oil has a good property – it converts to ketones easily – that I should post on sometime.

    MRE 

  7. I know this is an old post, but I’m interested in your take on something called “oil pumpkin” which is apparently grown in Austria. The seeds are hull-less and “high in polyunsaturated oils” and supposedly a “good source of omega-3” – we LOVE squash/pumpkin seeds as a snack, and I’d order these by the pound if I knew they weren’t too high in the omega-6 fatty acids – any opinions??

    I love to take raw squash/pumpkin seeds, wash and dry, toss with a bit of olive oil and sprinkle with smoked sea salt and roast at 400* for 10 minutes, or til they are just turning golden brown. They taste a lot like popcorn and make a nice portable snack, but I’m just unsure as to the health aspect of the little crunchers!

    Thanks!

    Hi Char–

    The squash/pumpkin seed crunchies sound pretty good. I don’t have my reference book with me that lists all the fatty acid contents of everything, but as I recall pumpkin seed oil contains a fair amount of omega-6 fat, which I’m not real crazy about. The whole seeds are a different story because they have the antioxidants within them to stabilize the oils.

    Cheers–

    MRE

  8. In Protein Power (1996) in the section on eicosanoids, you urged readers to avoid ALA containing oils, especially flaxseed oil, because they suppressed both Type I and Type II eicosanoids.

    Does this information still hold or has subsequent research changed the picture?

    Help! I have been taking 2-3 Tablespoons of flax oil (as salad dressing) and 1 tsp. lemon-flavored cod liver oil every day for several weeks and have not noticed any improvements over taking just fish oil alone.

    I updated the flax oil/fish oil info in the Protein Power LifePlan. I would stick with the fish oil (and/or krill oil) because the fatty acids you really want to get are EPA and DHA, both of which are in fish oil. The fish have done all the work for you of converting other fats into these two. Although flax oil is an omega-3 oil, it doesn’t contain EPA and DHA – you have to make the conversion yourself, which isn’t very efficient. If you take the fish oil that work is already done.

    Cheers–

    MRE

  9. Which will work better – fish oil or fish oil caps? Is there any difference in the way cap versus oil works?

    Not much difference now days. I always keep both capsules and oil in the fridge after I bring them home to keep them fresh and unoxidized longer.

  10. Hi, Mike: My holistic doctor recommended taking fish oil over flaxseed oil; however, I noticed that the fish oil has 45mg of chholesterol, and I can not find any listing of cholesterol on flaxseed oil; number two, as I do have moderate atherosclerosis, and I am trying to determine a treatment modality ( such as aspirin vs. fish oil or flaxseed oil) nattokinase and Vit. K 2 versus pravotatin, and the Dean Ornish diet recommends no more than 5 mg of cholesterol per day ( which is a diet that I am trying to incorporate), I am somewhat confused as to which way to go.

    Fish oil is a much better supplement than flax oil (and krill oil is better than both) because fish oil contains the fats EPA and DHA in large amounts. Flax oil contains the precursors for these fats, but your body has to do the job of conversion to EPA and DHA. To my mind it’s a lot better to get those fats already made and not worry about having to convert them.

    I wouldn’t worry about the tiny bit of cholesterol in the fish oil. But I also wouldn’t go on the Dean Ornish diet on a dare. So there you have it.

    Cheers–

    MRE