Omega-3 Supplementation: Not For Everyone

William Harris, MD, a vegan of 40 years, recently told me about his experiences with taking omega-3s, both ALA and DHA. He said that after taking ALA by way of ground up flaxseeds, 1-2 tsp per day for about 5 years, he started to bruise very easily, and on one occasion in December 2000 the bursa over his left knee spontaneously filled with blood without any previous injury. Thinking this might be due to excess synthesis of EPA from the ALA in the flax, he searched the literature and was able to find one supporting reference from a plastic surgeon, who was advising his face lift patients to stop the flax seed prior to facial surgery.

Harris decided to stop taking flax seeds and the easy bruising went away after 4 weeks. Four years later, after reading about DHA shortage in vegans, he started taking DHA supplements. After taking them for only 4 weeks, the bruising returned. He stopped taking the DHA and the bruising, once again, ceased.

It might be that Dr. Harris is an anomaly, but if anyone finds that they are having easy bruising, it might be best to stop taking or drastically cut back on any omega-3 supplementation.

A talk Dr. Harris gave to the Hawaiian Vegetarian Society last year, in which he goes into more detail about his thoughts on omega-3s, can be found here. The omega-3 discussion starts at 32:00.

In the video, Dr. Harris says that I think vegans need to take DHA. I am not so sure that vegans need to take DHA – the research is far from conclusive. But I would say that it is prudent (assuming they have no reason to think they are getting too much omega-3, as Dr. Harris was). Also note that Dr. Harris eats a very unprocessed diet, low in omega-6’s compared to the average vegan, and that could explain why he converts ALA into EPA more efficiently than your average vegan.

You can read more on omega-3’s in the vegan diet in Omega-3 Fatty Acid Recommendations for Vegetarians.

18 Responses to “Omega-3 Supplementation: Not For Everyone”

  1. Heather Katcher Says:

    Not to be confused with William Harris, Ph.D., the distinguished omega 3 researcher. I would have been surprised to hear that he was vegan! 🙂

  2. dragonfly mama Says:

    Thanks for the information. As important and Omega 3s are, I believe they may be overhyped like many “trendy” supplements. I made the mistake of overdoing flaxseed oil at first, and would bleed profusely from even the tiniest scratches inflicted by kittens I was fostering at the time!

    However, As a vegan long-distance runner it’s been my experience that (moderate) supplementation with algae DHA enhanced flaxseed oil has helped keep me injury-free due to its anti-inflammatory properties. Perhaps recommendations for vegan athletes are in order?

  3. WholeFoodsVeganMomma Says:

    No one seems to talk about the fact that the RDA for most people is 1.1 g, and that you can easily achieve this with a variety of plant foods. Greens, walnuts, soy foods, even grains and legumes contain this essential fat. It’s not just flax. So over the course of the day, if one is eating optimally (a lot of varied whole plant foods) the omega-3 requirement can easily be met without supplementation with flax. Perhaps supplementation is something a vegan would consider if they don’t daily consume many greens, beans, soy, ect.? Personally, although I know about omega-3’s being in many more plant foods other than flax (although in smaller amounts, but if you get a little bit from all of the food you eat, over the course of the day it adds up, right?) I have been doing 1 tsp. ground flax a day (for reasons other than the omega-3’s–good source of lignans, for example), but this post has caused me to rethink this choice, or at least look into it a bit more. Thanks for the info :).

  4. Jack Norris RD Says:

    > No one seems to talk about the fact that the RDA for most people is 1.1 g, and that you can easily achieve this with a variety of plant foods.

    It’s because 1.1 grams of short-chain omega-3s is generally not enough to provide a conversion of very much into DHA. The research to date indicates that the average person needs about 3 gram of alpha-linolenic acid to see an increase in DHA levels. You can read more about that here.

  5. Amelia Says:

    I am a new vegan and prior to my switch I was taking omega3’s via fish oil and was having no problem with bruising. My diet was not very nutrient dense all of the time, although I did try to eat a somewhat balanced diet. Now, I am a vegan 100% and I have started using Flax seed oil for my omega3s but I have been bruising at the slightest touch of anything on my body…my friends are asking if i’ve been beaten! Anyways, if this is true, and because my diet is so rich in the omega3s, should I consider stopping the supplement? I also have been thinking of taking an iron supplement, because it’s almost summer time and I cannot stand looking like a battered wives club member! I am sorry, no offense, I just need some help and answers to this weird issue!!!

  6. Jack Norris RD Says:


    I would suggest cutting way back on the flaxseed oil and seeing if that helps. If you can get your iron levels tested, that would be a good idea just to make sure you’re not deficient. The best way to increase iron absorption is to eat vitamin C with meals:

    Not getting enough zinc is also a possibility.

  7. Sue Says:

    My father and my grandfather both had burst brain aneurism type strokes. I bruise easily when taking advil and, since becoming a vegan about a year ago, when I supplement my food with ground flax and hemp seeds. I also add walnuts to many meals. Is it just flax, or is it all omegas? Are there foods that will “thicken” my blood? My son and husband do not have this problem. Thanks, very helpful info.

  8. Jack Norris RD Says:


    If you notice that you bruise easily when supplementing with flax, hemp, or walnuts then you shouldn’t do it, or significantly minimize it. You might also want to make sure your iron levels are healthy and that you get enough zinc.

  9. Brandon Becker Says:

    I started getting bruises after just a few weeks of DHA/EPA supplementation. It did it with a higher amount (400mg DHA + 200 EPA a day) and middle amount (200mg DHA + 100 EPA a day) and a slightly lower amount (200mg DHA + 50 EPA a day). I stopped taking the DHA/EPA supplements after I started getting bruises after a few weeks and I rarely ever bruise when not supplementing with DHA/EPA. This last time I took DHA/EPA supplements, it was at the level of 320mg DHA + 130 EPA and I also took iron supplements every other day along with increasing my vitamin C consumption with meals and it’s been almost two months now without any bruising.

    I should also note that my iron levels were really good before I even started any DHA/EPA supplementation so I’m hoping the iron supplementation won’t bring my iron levels up too high but I won’t know until my annual blood test in a few months. The only alternative to this plan seems to just eat high omega-3 foods like flax or chia seeds and assume my body is doing the conversion work from ALA to DHA/EPA. My wife is in the same predicament.

  10. Jack Norris RD Says:


    Why don’t you try a DHA supplement with no EPA? The EPA is to “thin” the blood and it sounds like that is not a problem for you.

  11. Brandon Becker Says:

    Is DHA-only as effective as DHA+EPA? If it works and I can avoid bruises taking DHA-only, that would be great. I would also keep eating ALA to go along with the DHA supplement.

  12. Jack Norris RD Says:


    I recommend omega-3 supplement for DHA, not EPA. That’s the important molecule that vegans have much less of and that can’t reliably be gotten from more ALA. In general, EPA is for heart disease, which I’m not so worried about for vegans, whereas DHA is for cognition. EPA is what would be causing your bleeding (though because DHA can be converted into EPA at a low rate, supplementing with DHA can increase EPA levels, but not as much as taking an EPA supplement).

  13. Brandon Becker Says:

    Thanks for the informative explanation. I’ll definitely switch to DHA-only when my current bottle runs out. I appreciate your help!

  14. Brandon Becker Says:

    After a few weeks of not supplementing DHA/EPA, I’ve decided that I’m not going to take DHA/EPA supplements anymore. DHA/EPA supplements are really expensive, I’ve never felt any different taking them (even at high doses of 500mg/day), and I always end up bruising (even with DHA-only and I rarely bruise otherwise). Until there is solid evidence that vegans need DHA/EPA supplements rather than just speculation, B12 will be the only supplement I’ll regularly take.

  15. Susan Michael Says:

    For the last two months as I have become a vegetarian I decided to take Omega-3 flax seed oil & Vitamin E supplements daily together with Vitamin B12. I have noticed a lot of painful bruises on me over the past week and wondered what was causing them because I’ve never experienced them before without any justifiable injury. I was very worried and I was blaming Vitamin B12. I like to thank you for this information and I feel much better knowing that perhaps the culprit of my new problem is the Omega- 3 rather than the Vitamin B12. I will stop supplementing with flax seed oil at once and keep a watchful eye from now on.

  16. Rosita Says:

    I think I am experiencing this the past few weeks. Can anyone explain the science behind it? I injured myself in what should have been a minor fall, and I’ve had some bruising in odd places. Also, which of the following would do this?: flax, chia, nuts, seeds…? I did have more flax/chia before this started happening. What about garlic? Would it have an effect?

  17. Jack Norris RD Says:


    If someone starts consuming large amounts of omega-3 fatty acids and they notice they are starting to bruise more than usual, it could be due to the omega-3. Flax, chia, and walnuts will have a lot of omega-3, but other nuts don’t.

  18. CZ Says:

    SO glad I found this article. I’ve been taking flaxseed oil for over a month and just started noticing big deep dark purple bruises in areas where I have barely bumped into anything and I have NEVER bruised easily. I’m definitely stopping it!

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