More on Omega-3 Fats in Vegan Diets

Based on some emails I received about my blog post from November 17, I realize that there is a little bit of confusion about the different types of omega-3 fats. I want to clear that up so that readers can make the best informed decision about meeting needs for these compounds.
There are two different type of omega-3 fats in foods. We definitely need one of these and may need the other.
Alpha-linolenic acid (ALA) is a short-chain omega-3 fatty acid that is an essential nutrient. We absolutely need to have some in our diet. It’s provided by just a few plant foods but requirements are so small that it’s easy to get enough. You can meet your entire needs for the day by consuming a teaspoon of flaxseed oil or a tablespoon of canola oil or 3 to 4 walnut halves.
DHA and EPA are the long-chain omega-3 fats that are found in fish oils. Although there is a little bit of EPA in sea vegetables, vegans generally don’t consume these fats at all. While DHA and EPA are not considered essential nutrients (there is no RDA for them), they are linked to some health benefits including reduced risk for heart disease. Low levels of DHA may raise risk for depression and, in older people, cognitive decline.
Even though vegans don’t consume these fats, we do have some in our blood because the body can make DHA and EPA from the essential fat ALA. The problem is that it takes a lot of ALA–maybe more than is actually healthy–and the conversion doesn’t seem to be very efficient. There is some evidence, including the findings from the EPIC-Norfolk study I wrote about, that the conversion is more efficient in vegetarians than in meat-eaters. But even so, vegetarians’ blood levels of EPA and DHA are generally lower than those of people who consume fish.
So, everyone needs to consume some source of ALA no matter what; it’s an essential nutrient. Even if you are taking DHA supplements, you still need ALA in your diet because it has its own set of functions.
And consuming ALA from flaxseed or hemp oil or other foods does not necessarily mean that you’ll end up with optimal DHA levels. Taking DHA supplements from algae is effective in raising levels of both DHA and EPA in the blood (some of the DHA converts back to EPA). But whether or not vegetarians benefit from those higher levels isn’t known.
If you want to know everything in the world about omega-3 fats in vegetarian diets, I recommend the section covering this topic on veganhealth.org.

8 Responses to More on Omega-3 Fats in Vegan Diets

  1. Mark November 19, 2010 at 7:14 pm #

    Hi Ginny,
    Thanks for your wonderful blog. As far as ALA goes, do you think Jack Norris's veganhealth.org recommendation of 1 tsp ground flaxseed per day is enough? Or would you suggest more?
    Just wanted to get your opinion.
    Mark

    • Ginny Messina November 21, 2010 at 11:57 am #

       I think that Jack's recommendation is based on the idea that people will be getting ALA from some foods but maybe not meeting needs unless they make a concerted effort to eat at least one good source per day. So his recommendation is meant to give your ALA intake a good boost but not necessarily provide the total amount that you need. So if this were your only source of ALA, I'd recommend more.

  2. Mork December 6, 2010 at 7:35 pm #

    I've tried very hard to find a high DHA suppliment that is not fish oil and have failed.  I thought they didn't exist.  Can you give me some recommendations on where to find this?  Is the alge version of DHA alone or is it a part of Omega-3 with EPA like fish oil?
    Just as a side note, I used to rely on high DHA fish oil suppliments to help keep my mood stable.  (I was never diagnosed as bi-polar but I had serious mood swings and probably would have been eventually.)  The fish oil kept me stable, but not completely.  When my doctor discovered that I was vit D deficiant and prescribed D2 pills, I experienced a radial change in my mood issues.  I feel so much better now.   I know if I've been slacking too much with the supplimentation because my moodiness comes back.  I wonder if these two substances work together somehow.

  3. Shannon January 21, 2011 at 2:13 pm #

    Hi Mork!
    Here are links to two vegan DHA/EPA supplements:
    http://store.veganessentials.com/deva-omega-3-dha-supplement-p1327.aspx
    http://www.v-pure.com
    :)

  4. Chris Dove January 30, 2011 at 7:22 pm #

    In response of the human capability of ALA to DHA conversion, John McDougall puts it in perspective with this statement:
    The possibility of brain damage, especially to the unborn or young children, strokes the emotional cords of our hearts.2 A number of writers claim that only a diet based on seafoods can provide the necessary quantity of essential fat (docosahexaenoic acid) to support the human brain and that a switch to such a diet early in human evolution was critical to human brain evolution.2,3 However, a critical review of this claim by John Langdon of the departments of Biology and Anthropology of the University of Indianapolis came to this conclusion, “There is no evidence that human diets based on terrestrial food chains with traditional nursing practices fail to provide adequate levels of DHA or other n-3 fatty acids. Consequently, the hypothesis that DHA has been a limiting resource in human brain evolution must be considered to be unsupported.”3  
    Only plants can make the omega-3 fats—fish don’t; nor do cows or people.  Alpha linolenic acid (ALA) is made by plants and converted into DHA by infants and adults in sufficient amounts to supply all of our needs including those for brain function and development.  After all, the African elephant with a brain volume of 3000 to 4000 cm3, compared to the human brain of 1400 cm3, has no trouble making all the essential fats its brain, and the rest of its huge body, needs from plant foods.3 You can safely assume a comparatively puny human being can do the same.

  5. Derek April 16, 2012 at 1:53 pm #

    DHA vs EPA – it seems if one takes only alga-derived DHA pills the body will make enough EPA? Is this true? I’m having a hard time learning if there a need for EPA in addition to DHA (most alga-derived omega 3 pills are DHA-only.) DHA is often marketed as pre-natal and better for body growth than EPA which seems more important for maintenance etc. Thoughts? Thanks!

Trackbacks/Pingbacks

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    [...] There are two types of healthy fats known as omega-3′s: short-chain alpha-linolenic acids (ALA), and long-chain omega-3 fats known as DHA and EPA. Humans definitely need ALA: it’s an essential nutrient, contained in just a few plant foods like flaxseed, chia seed, hempseed, canola oil, full-fat soy foods, and walnuts. Daily requirements are small, though, so that you can get all you need in just ‘a teaspoon of flaxseed oil or a tablespoon of canola oil or 3 to 4 walnut halves.’ [...]

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    [...] There are two types of healthy fats known as omega-3s: short-chain alpha-linolenic acids (ALA), and long-chain omega-3 fats known as DHA and EPA. Humans definitely need ALA: it’s an essential nutrient, contained in just a few plant foods like flaxseed, chia seed, hempseed, canola oil, full-fat soy foods, and walnuts. Daily requirements are small, though, so that you can get all you need in just “a teaspoon of flaxseed oil or a tablespoon of canola oil or 3 to 4 walnut halves.” [...]

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