Why Fish Stomps Flax as a Source of Omega-3 | Chris Kresser
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Why Fish Stomps Flax as a Source of Omega-3

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I want to thank everyone for sending in their questions and voting on the next topic. The good news is that there’s a lot of interest in all of the topics I’m researching right now. The bad news is that there was no clear winner.

I’ve decided to go ahead with the series on fish and fish oil, but I may write about thyroid and diabetes simultaneously. I’m also going to experiment with shorter (although I’m clearly breaking that rule here), but more frequent, articles. Hopefully these will be easier for me to write and for you to read.

Finally, stay tuned for the first episode of The Healthy Skeptic audio podcast, coming up next week. I’ll be interviewing Stephan Guyenet, Ph.D, on the subject of obesity and weight regulation. Stephan is a senior fellow at the University of Washington studying the neurobiology of body fat regulation. He’s also the author of Whole Health Source, which is one of my favorite health related blogs.

Before we get into talking about the benefits of fish consumption, or how how much fish or fish oil you should eat, it’s probably a good idea to start with a basic review of the omega-3 fatty acids.

Essential Fatty Acids 101

A fatty acid is a chain of carbon, oxygen and hydrogen atoms with a carboxyl group on one end. Fatty acids are classified on the basis of how many carbon atoms are in the chain, as well as how many double bonds exist within the molecule.

Fish contain a variety of fatty acids, but the ones that are believed to confer the majority of the benefits are the long-chain omega-3 fats eicosapentanaenoic acid (EPA) and docosahexaenoic acid (DHA). These omega-3 fats are found exclusively in seafood and marine algae.

As you can see from the chart below, it is also possible for the body to synthesize EPA and DHA from the short-chain omega-3 alpha-linolenic acid (ALA). ALA is found in plant foods such as flax, hemp and pumpkin seeds and walnuts.

Click thumbnail for a larger version

However, research clearly indicates that the conversion of ALA to EPA and DHA is extremely limited. Less than 5% of ALA gets converted to EPA, and less than 0.5% (one-half of one percent) of ALA is converted to DHA.

A common misconception, especially amongst vegetarians and vegans, is that our need for EPA and DHA can be met by consuming flax oil and other plant sources of ALA. But the conversion numbers above clearly indicate that this isn’t the case.

Studies have shown that ALA supplements (like flax oil) are unable to raise plasma DHA levels in vegans, despite low DHA levels at baseline. (ref) So unless they are supplementing with an algae-derived source of DHA, it is likely that most vegetarians and vegans are deficient.

This is significant because researchers now believe that the majority of the health benefits we get from dietary omega-3 fats come from the longer chain derivatives (especially DHA, as I will explain below).

Is DHA essential?

In fact, some researchers have proposed that DHA is essential. When scientists label a nutrient as “essential”, they they’re not just saying that it’s “very important”. In the context of nutrition essential means that the nutrient cannot be synthesized in the human body, and must be derived from dietary sources.

According to today’s nutrition textbooks, there are only two essential fatty acids, omega-6 linoleic acid (LA) and omega-3 alpha-linolenic acid (ALA). It is believed that as long as these fats are present in the diet, all of the longer-chain omega-3 and omega-6 derivatives can be synthesized in the body.

As I pointed out above, while this is theoretically possible, in reality the conversion doesn’t work well. This is true even for healthy people, but it’s especially true for those with nutrient deficiencies, because the conversion of ALA to DHA depends on zinc, iron and pyridoxine.

The bioavailability of iron in plant sources is poor compared to animal sources, so iron deficiency is common in vegans and vegetarians. This is another reason why they tend to be poor converters of ALA to DHA.

Several other observations support the hypothesis that DHA is essential:

  • DHA content in the tissues of all mammals is very similar despite widely varying intakes of omega-3 fatty acids. 1
  • DHA and AA, but not other omega-3 or omega-6 fatty acids, are selectively transferred across the placenta (PDF).
  • 60% of the dry matter of the brain is lipid, and DHA and AA are the most abundant fatty acids of brain phospholipids (PDF)
  • DHA status in newborns is much lower in those receiving formula with LA and ALA, than in those receiving milk or formula with pre-formed DHA (PDF)

It is possible that the primarily carnivorous diet of our ancestors, which ensured a consistently high dietary intake of DHA and AA, precluded the need to evolve efficient conversion mechanisms.

In other words, since we were eating a lot of meat and fish with pre-formed DHA and AA, our bodies didn’t need to be experts at converting ALA and LA in plants to DHA and AA. It is far easier for the body to assimilate pre-formed DHA and AA than it is to synthesize them from precursors.

What about EPA? Isn’t it essential too?

EPA is another long-chain omega-3 fatty acid that is conventionally believed to be responsible for the benefits of fish consumption.

EPA is often referred to as “anti-inflammatory”. However, according to this report on essential fatty acids by Masterjohn, EPA’s effect seems to be more of an interference with the metabolism of omega-6 arachidonic acid (AA) than the performance of any essential role itself.

Take a look at the chart again that I linked to in the beginning of the post. The fatty acids in blue boxes are less inflammatory, and those in pink boxes are more inflammatory. The chart shows that AA is used to synthesize prostaglandins that cause inflammation (indicated by the pink box on the chart). Because it has the same number of carbon atoms, EPA competes with AA for the enzymes that metabolize it. Since the prostaglandins made by EPA are less inflammatory than those made by AA (indicated by the blue box), EPA is often referred to as “anti-inflammatory”.

But while EPA is certainly less inflammatory than AA, it doesn’t make sense that the body would require an essential fatty acid just to block the inflammatory effects of of another fatty acid.

By contrast, DHA is used to synthesize compounds that play an active role in resolving inflammation. EPA only makes these compounds in the presence of aspirin (PDF). EPA is thus likely to simply be a byproduct of compromised DHA synthesis.

What does this mean to you?

Putting all of this information together yields the following conclusions:

  1. DHA is the most important of the omega-3 fatty acids, and is primarily responsible for the benefits we get from consuming them.
  2. DHA is likely to be essential, which means that you must consume it in the diet to prevent disease and ensure optimal function.
  3. The conversion of plant sources of ALA, such as flax seed oil, to DHA is poor in healthy people and even worse in people deficient in certain nutrients. Vegans and vegetarians are especially prone to be poor converters of ALA to DHA.
  4. If you’ve been buying flax oil in the hopes that it will help, you’d be far better off putting that money towards some fish or fish oil capsules.
Dietary changes over the past century have lowered the DHA status to a state of subclinical deficiency in many people. Countless studies show that this deficiency is at least in part to blame for the rising incidence of cardiovascular disease, inflammatory disease, mental and psychiatric disorders and suboptimal neurodevelopment.

DHA is not the only reason to eat fish, which is also rich in selenium and vitamin D. However, DHA is likely to be the primary reason why populations that eat fish on a regular basis have consistently been shown to healthier than those that don’t. We’ll discuss this further in the next article.

  1. Jones PJH, Kubow S. Lipids, Sterols, and their Metabolites. In: Shils ME, et al., eds. Modern Nutrition in Health and Disease: Tenth Edition. Baltimore, MD; Philadelphia, PA: Lippincott Williams & Wilkins (2006) pp. 92-122.

248 Comments

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  1. I’m not sure about that (farmed fish containing EFAs that aren’t useful).  I haven’t seen any mention of it in the literature.  But there are several other reasons to avoid farmed salmon, as you probably know.

    If fresh wild salmon is hard to come by, you might try ordering canned wild salmon from Vital Choice.

    • It’s irresponsible and selFISHly to encourage people to consume wild fish! Of course depletion of oceans and rivers and lakes is no concern of yours!

  2. Thanks Chris. I had read somewhere that farmed fish did not contain an omega 3 that was useful to the body, but didn’t know what to make of it. Have you ever heard of this? Or, is the quality of n-3 the same, and the only difference is the quantity? It’s rather difficult to source wild salmon and tuna and salmon are the only fish I really enjoy eating.

  3. Great article (as always) Chris. Question: Have you found any differences between algae containing DHA vs. just eating fish? Also, Do you know of any differences between farmed fish (i.e. farmed salmon) vs. wild salmon in regards to DHA levels?

    • Whole fish has selenium, vitamin D (in some cases) and protein. It’s a more complete food, and absorption of the EFAs is better than it is in oils or capsules as I explained in another article. Wild salmon often has more DHA than farmed from what I’ve seen.

  4. Thanks so much for writing this series of articles on fats and fish oils, I recently converted to a paleo diet and eating too many nuts and not enough fish has been my major downfall, this has given me the motivational kick up the arse I needed to get it together and sort it out. I love your site, keep up the great work, it’s very much appreciated!
    Take care,
    Khrystyna

    http://foodfloraandfelines.blogspot.com/

  5. Hi, great post and podcast.
    I know fish oil stomps flax, but I have two questions:
    Do plant-based n-3 oils “count” in our caloric balancing act of n-3 and n-6, even if 99%  of it doesn’t get converted?
    Is it possible that the unconverted 99% is valuable and healthy in some other way besides simple conversion to DHA and EPA?
    Thanks for your work.
     

    • N-3 still counts in the ratio, but you’d want to emphasize EPA & DHA. And yes, it’s possible that ALA has some benefit but studies definitely suggest that the bulk of the benefit comes from EPA & DHA.

  6. Hi Tracee,

    Thanks for sharing your experience.  Yes, there is still much we don’t know – especially about the relative importance of EPA and DHA.  It’s interesting to hear that EPA is more effective for your son.

  7. I love your series.  Adding omega-3 supplementation while decreasing omega-6 in our diets was our first diet change that my son’s autism made big improvements on (the SCD was the other drastic improvement). For some reason, the research points to autistics doing better with a higher EPA to DHA ratio (the reverse for ADHD). My son is more bright-eyed  with a higher EPA blend. I had also found  a journal article that showed EPA seemed to be protective against LPS. So maybe there’s more to the EPA thing than we can tell?

  8. @Robert Jacobs – I know that fish oil has been one of the most significant contributors to my remaining relatively mentally healthy without all the psychiatric drugs my doctors had me on a merry-go-round of.  As Dr. Stoll suggests that EPA is the major reason for this, I am thankful.  Note that Dr. Stoll convinced his wife so much of his studies that she started a company producing OmegaBrite, a product with a 10:1 ratio of EPA:DHA, even though Dr. Stoll’s studies said nothing about other than a 3:2 ratio of them.
     
    @Chris Kresser — Thanks for more articles.  I’m going over there to read them now.

  9. Moss,

    I agree with you on that.  I’ve seen some interesting evidence which contradicts the “savannah hypothesis”, and suggests instead that hominids evolved along the edges of lakes as Dr. Stoll reports.

    We won’t see any sources from SN.  There aren’t any.

    • Of course there aren’t any, Chris. We all know that meat was available to many of our ancestors. What our bodies are biologically best suited to is an unrelated matter. Someone 1,000 years from now could look at us and conclude that fast food is healthy because our average life expectancy is well over 70.

      I’ve been trying to figure out a few things: if most mammals have omega-3’s in their tissues despite varying intakes, then where are they getting them from? Couldn’t one use that argument to say “hey, humans consuming healthy diets don’t need omega-3’s because their bodies will make it.” This makes me wonder if blood levels of DHA are really telling the story. If most of the DHA is taken up into tissue, then blood samples wouldn’t tell us much. I’m just wondering because I’ve recently started taking fish oil supplements, and now I’m wondering whether it’s really worth it. Sure, people that have heart disease probably need them, but they weren’t healthy to begin with.

      • There is some compelling information in the book entitled “Catching Fire: How Cooking Made Us Human” by Richard Wrangham. He paints a detailed picture of our evolution and brain growth and describes exactly what our bodies are designed–by evolution–to digest. Whether fish or meat or vegetables, the fact of the matter is, we are a cooking ape, and it is this advancement that has brought us into the modern world.

    • There had to be a clean water supply inland as well as on the coast where many fished for food. Since animals lived on the Savannah as well, then one could suppose that ancient hominids had the same water supply, but this would have been fairly dangerous. It is bizarre to me how some people like Welsh writer Elaine Morgan, who wrote a series of books on the topic, think that they are correct by expanding the idea to where we were walking around in the water most of the time, therefore losing our hair.

      From Wikipedia:

      The aquatic ape hypothesis (AAH), often also referred to as aquatic ape theory (AAT) is a proposal that the evolutionary ancestors of modern humans spent a period of time adapting to a semiaquatic existence. The hypothesis was first proposed by German pathologist Max Westenhöfer in 1942, and then independently by English marine biologist Alister Hardy in 1960.

      Extant scientific consensus is that humans first evolved during a period of rapid climate fluctuation between wet and dry, and that most of the adaptations that distinguish humans from the great apes are adaptations to a terrestrial, as opposed to an earlier, arboreal environment. Few paleoanthropologists have explicitly evaluated AAH in scientific journals, and those that have reviewed the idea have been critical. The AAH is one of many hypotheses attempting to explain human evolution through a single causal mechanism, but the evolutionary fossil record does not support any such proposal. The proposal itself has been criticized by experts as being internally inconsistent, having less explanatory power than its proponents claim, and suffering from the feature that alternative terrestrial hypotheses are much better supported. The attractiveness of believing in simplistic single-cause explanations over the much more complex, but better-supported models with multiple causality has been cited as a primary reason for the popularity of the idea with non-experts.

  10. Ditto, SN.  Show me your sources.
     
    The anthropologists who talked with Dr. Stoll for his book indicated that, at some point in our evolution, there were several hominid species competing, and the tribes that lived along the lake (spearing and eating fish) were the ones whose brains grew, enabling them to out-compete the other tribes and causing the final step in Homo sapiens.

    • Eskimos eat tons of fish for thousands of years. Yet they don’t appear to be so intelligent otherwise they would not have been living in ice cubes all this time. They would have invented electricity way before Farraday. Fact is it doesn’t make you smart at all.

      • The term is Inuit and their way of life is what it is. Invention is derived out of necessity. Their life style didn’t need it. On another note Inuit people have a significantly lower rate of heart disease and cancer. All of that from seal blubber and arctic char.

        Four year old article by the way

      • What an interesting interpretation how to measure intelligence. I suppose I could counter that modern man must not be very intelligent with our high rates of obesity, CVD, diabetes, atherosclerosis, arthritis, osteoporosis, alzheimer’s, etc., etc., etc. Ajith: I would love to see how well you would fare if you were placed in a village of a pre-historic tribe, or even a more modern village, and forced to fend for yourself. Trust me: you would not feel very “intelligent”.

  11. Our ancestors were never primarily carnivorous. Animal based foods were few and far between until modern humans … and even then animal based foods were few and far between for all but the most wealthy until very recently in our history. When there’s such a glaring mistake, it’s hard to take any of your other “facts” seriously.

    • SN,

      Show me one study published in a reputable journal that supports your viewpoint. The idea that animal foods were “few and far between” is absurd.

      • No use in commenting about human diet million years ago, they were eating meat, for sure, but if somebody gave them the knowledge of planting, manipulating and multiplying plants…

        The world is not America solely! Some 100,150 years ago, in Europe, many populations depended on potatoes or grains or beans, eating meat was a rare occasion for many rural and urban populations back then, once a week or even rarer!

      • Your statement that our Paleolithic ancestors were primarily carnivorous isn’t supported by the research either (and it takes more than just “one study” to prove a hypothesis)

        We simply don’t know the proportions of meat to plant foods, and it likely varied from area to area (e.g more meat in cold climes)

        Wikipedia has a good summary of the research: http://en.wikipedia.org/wiki/Paleolithic#Diet_and_nutrition

    • If we were never primarily carnivorous, or if our diet never contained significant amounts of meat, I’d suggest evolution shouldn’t have ensured we each possessed 8 incisor and four canine teeth, and I’d also suggest you are a Vegetarian or Vegan yourself, and if this is the case it would explain your views which are based not on any evidence whatsoever.

      Stating that animal based foods weren’t available in any quantity to anyone except the most wealthy until recently is ludicrous in the extreme, as it is only relatively recently that ‘the most wealthy’ even existed; what did native Americans eat before Columbus for instance, and what do the most primitive tribes eat now? I think you’ll find it’s a similar diet to the great apes – meats, fruits and vegetables, the definition of omnivorous.

      • Great apes don’t eat meat though… Chimps are the only ones that eat some, and it’s less than 2% of their diet… And did you see the canines on those guys?

    • This is incorrect. Just look at the work of Dr. Weston A Price. http://www.westonaprice.org/about-the-foundation/dr-price-movie

      Dr. Weston A. Price (1870-1948), a Cleveland dentist, has been called the “Isaac Newton of Nutrition.

      He has proven that the reason tribes were so healthy was because they ate meat and thereby received the necessary nutrients for health. Sugar and white flour were unknown to them at this time in history. Please read and be informed.

  12. Is it true that all polyunsaturated fats have omega-6 and omega-3s?
    Similarly, would all monounsaturated fats contain omega-9s?

    • Not exactly. A polyunsaturated fat is a fatty acid with more than one double-bond. Omega-6 and Omega-3 are different types of polyunsaturated fatty acids. It is true that many foods have a range of fats in them, including polyunsaturated (omega-3 and omega-6), monounsaturated (n-9 and n-7) and saturated. When we refer to a “saturated fat”, like coconut oil, we’re referring to a fat that is primarily made up of saturated fatty acids. Coconut oil is 92.1% saturated fat, 6.2% monounsaturated, and 1.6% polyunsaturated. Most fats have a more even distribution of fatty acids. All monounsaturated fats will contain at least some omega-9.

  13. Chris,
    I’d like to thank you for inspiring me to actually take my algal oil. The capsules are so big that I hadn’t been able to swallow them before tonight. It’s so much more pleasant to swallow them than to break them open and mix them into my oatmeal.
     
    Also, what exactly does DHA DO? What happens if we don’t get enough?

  14. @Chris Kesser – EPA content in the body could easily be overestimated, but brain content is quite high.  Dr. Stoll’s tests, and others, show that DHA has less effect on mental processes, specifically aiding proper firing of neurons, than EPA does.  Almost beside the point – fish oil is better than flax, hemp, etc.
     
    We could use some studies on GLA.  There are a few positive indications in mental health, but I have yet to see verifiable studies.

  15. Chris   —
    Right. I know you have done so, by the comments you have made and your writings.  I look forward to your next piece.  Keep up the good work.

  16. Could you please comment as to the amount of fish, and what types we should be consuming? Salmon and sardines are my favorites, but are there others high in omega 3’s? thank you

  17. Thanks for a good piece on Omega 3’s.  I agree that fish is healthy, and, if one wants Omega 3’s (I still remain skeptical that this is true), fish is probably the best source.
    It has long been a primary belief of mine that whatever is commonly promoted and sold to consumers is probably not healthy, or that the kernel of truth regarding the issue is seriously misunderstood.  That makes me a skeptic of nearly everything.  However, from my previous readings (these are sources cited by others, not me, I am just a layman trying to figure things out) some research seems to have doubts about DHA and all Omega 3’s.  Just thought I send some of their references:

    Free Radic Res. 2001 Apr;34(4): 427-35. DHA supplementation increases oxidative damage in bone marrow DNA in rats and the relation to antioxidant vitamins. Umegaki, et al.
    J Physiol. Feb 15;475(1):83-93. Facilitatory effect of DHA on N-methyl-d-aspartate response in pyramidal neurons of rats’ cerebral cortex. Nishikawa, et al.
    [ I think this entire piece is worth a read ] : http://raypeat.com/articles/articles/fishoil.shtml

    Am J Clin Nutr. 2004 Nov;80(5):1167-74. Docosahexaenoic acid concentrations are higher in women than in men because of estrogenic effects. Giltay EJ, Gooren LJ, Toorians AW, Katan MB, Zock PL. “The proportion of DHA was 15 +/- 4% (x +/- SEM; P < 0.0005) higher in the women than in the men. Among the women, those taking oral contraceptives had 10 +/- 4% (P = 0.08) higher DHA concentrations than did those not taking oral contraceptives. Administration of oral ethinyl estradiol, but not transdermal 17beta-estradiol, increased DHA by 42 +/- 8% (P < 0.0005), whereas the antiandrogen cyproterone acetate did not affect DHA. Parenteral testosterone decreased DHA by 22 +/- 4% (P < 0.0005) in female-to-male transsexual subjects. Anastrozole decreased estradiol concentrations significantly and DHA concentrations nonsignificantly (9 +/- 6%; P = 0.09). CONCLUSION: Estrogens cause higher DHA concentrations in women than in men, probably by upregulating synthesis of DHA from vegetable precursors.
    Neurobiol Aging. 1982 Fall;3(3):173-8. Lipid peroxides in brain during aging and vitamin E deficiency: possible relations to changes in neurotransmitter indices. Noda Y, McGeer PL, McGeer EG. “Lipid peroxide levels, were found to be significantly higher in brains of 18 month old as compared to 4 month old rats, with particularly large increases occurring in the olfactory bulb, globus pallidus, cerebral cortex and caudate-putamen (CP). Eighteen month old rats fed a vitamin E deficient diet for 9 months before sacrifice had lipid peroxide levels significantly higher than age-matched controls in the cerebral cortex, hippocampus and hypothalamus.” “Age-related decreases were seen in choline acetyltransferase, acetylcholinesterase and 3H-QNB binding in some but not all brain regions, while GABA transaminase and MAO showed age-related increases.” “As compared with controls, vitamin E deficient rats showed decreases of 38% in cortical 3H-DHA binding, of 33% in 3H-QNB binding in the CP and of 23% and 12% in choline acetyltransferase in the CP and cerebellum, respectively.”

    Naunyn Schmiedebergs Arch Pharmacol. 2005 Mar;371(3):202-11. Epub 2005 Apr 15. Antiarrhythmic and electrophysiological effects of long-chain omega-3 polyunsaturated fatty acids. Dhein S, Michaelis B, Mohr FW. “Atrioventricular conduction time was slowed only by DHA and EPA.” “Regarding antiarrhythmic activity we found that the threshold for elicitation of a ventricular extrasystole was concentration-dependently enhanced by DHA and EPA, but not by ALA. DHA dose-dependently reduced longitudinal propagation velocity V(L) and to a lower extent transverse velocity V(T).”
    J Biol Chem. 2002 Oct 18;277(42):39368-78. The mechanism of docosahexaenoic acid-induced phospholipase D activation inhuman lymphocytes involves exclusion of the enzyme from lipid rafts. Diaz O, Berquand A, Dubois M, Di Agostino S, Sette C, Bourgoin S, Lagarde M, Nemoz G, Prigent AF. “Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid that inhibits T lymphocyte activation, has been shown to stimulate phospholipase D (PLD) activity in stimulated human peripheral blood mononuclear cells (PBMC).” “This PLD activation might be responsible for the immunosuppressive effect of DHA because it is known to transmit antiproliferative signals in lymphoid cells.”
    J Nutr 2000 Dec;130(12):3028-33. Polyunsaturated (n-3) fatty acids susceptible to peroxidation are increased in plasma and tissue lipids of rats fed docosahexaenoic acid-containing oils. Song JH, Fujimoto K, Miyazawa T.. “Thus, high incorporation of (n-3) fatty acids (mainly DHA) into plasma and tissue lipids due to DHA-containing oil ingestion may undesirably affect tissues by enhancing susceptibility of membranes to lipid peroxidation and by disrupting the antioxidant system.”

    • Robert,

      I’ve read a lot of Ray Peat’s stuff, as well as other research suggesting n-3s aren’t essential. Overall, I believe the epidemiological and clinical evidence supports the hypothesis that DHA reduces CVD mortality and improves other outcomes. I’ll be covering this in more detail in subsequent posts in this series.

    • but im wondering if tests on mice are even relevant at all, because our need and efficient use of DHA probably comes from being a species that ate alot of fish during our evolution, we always lived near rivers because of the fresh water and fish.

  18. The studies on mental health benefits all point to EPA, not DHA, as the primary agent.  See also The Omega-3 Connection by Andrew Stoll, M.D., of Harvard Medical School.  Nonetheless, fish oil is the almost-sole direct source of EPA.  Good article.

    • Many studies suggesting EPA provides the greatest benefit are flawed. They are conducted in humans consuming a massive excess of linoleate; they have used very small amounts of ALA; they measure blood levels instead of tissue levels; and they don’t take into account vitamin B6 status or any of the other variables that affect desaturase activity.

      The standard American diet is excessively high in LA (at least fifteen times the required amount). LA depresses the production of DHA, especially if the intake of ALA is low (as it often is in the U.S.) Since DHA, but not EPA, is preferentially incorporated into tissues, measuring blood levels probably overestimates EPA and underestimates DHA.

      The EPA content of terrestrial animal products, even those rich in DHA, is minimal. While DHA content in tissues is very similar across all mammals, the same is not true for EPA.

      For these reasons I believe the role of EPA has been overestimated.

      • It is fascinating to me how studies conducted on unhealthy subjects can throw off results and lead scientists to totally irrelevant and incorrect conclusions. How much of our current research is flawed due to these “hidden” variables.

        • Peggy, I find it equally distressing, if not more so, that they test drugs for treating diagnoses on healthy patients, not on patients with the disorder they aim to treat. How can they find out the efficacy of a medication by testing it on someone who does not have the problem?

        • Moss,

          I agree. The gravity of that reality is that as populations become sicker, the data becomes more skewed. I’ve really gotten to the point where I hesitate to believe much of what I read in general medicine. I have D.O. who is very holistic, but is a vegan, and sometimes getting through to her on issues of cholesterol levels (particularly particle counts and HDL/LDL talk) and sources (eggs are bad she says…. not) is tough. We live in a country where one of the top three killers is admittance into a hospital for care. Is that a sign of where we’re at, or am I being too judgemental?

      • Not sure about the comment on vegetable sources of iron. Actually anemia is as common and if not more so amongst meat eaters than many vegetarians. There are plenty of vegetarian foods with available iron. The problem with vegetarians is usually one of gut flora.

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