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What's are the conversion rates for omega-3 to DHA?

Discussion in 'The Epi-Paleo Diet' started by Glenn A, Nov 29, 2018.

  1. Glenn A

    Glenn A New Member

    Digging into this subject, I find that the conversion rate to DHA from the parent omega-3, alpha-linolenic acid (ALA), varies widely. After study, I'm lead to believe that on an Epi-Paleo Diet, with minimal external stressors that raise requirements, pushing to ingest preformed DHA as via supplements or food fortification may not be necessary.

    See below the listed points for some amplification on these points:
    1. Yes, DHA is vital for health and to avoid degeneration, especially of the nervous system and eyes.
    2. Dr. Kruse has great proof that DHA, once in the system, recycles nicely (SN-2) avoiding the need for replacement.
    3. Therefore, minimal additional DHA is needed during adult life compared to infancy.
    4. All but about 23% of DHA is already installed in SN-2 position by the time a child becomes 3 years of age.
    5. Preformed, exogenous DHA is usable by the body, though sometimes not as well as endogenously derived.
    6. Derivation of DHA from the parent ALA in the liver's endoplasmic reticulum occurs at different rates.
    7. The amount of omega-6 consumed affects the amount of DHA derived from ALA.
    8. A scarcity of preformed, dietary DHA will raise the conversion rate, by up to 50% or more (eg, in vegetarians).
    9. Women, and especially those of child-bearing age, have up to triple the conversion rate of adult men.
    10. Pregnant women may have even higher rates as they must provide DHA to the placenta.
    11. The placenta does no ALA to DHA conversion, though the fetal liver may in the third trimester.
    12. The percent of DHA derived in the mother's liver that passes to the placenta is limited, sparing some for self.
    13. Supplemental DHA given to infants shows in blood cell content, but IQ is not significantly improved to age 7.
    14. DHA level in breast milk varies widely, based on the mother's diet.
    See Dr. Jack Kruse's article for an explanation of some terms (SN-2) and how the light spectrum we expose ourselves to affects our health, including how our DHA performs, once installed.


    Regarding 7 -- Either based on a ratio between, or on absolute quantities of, omega-6 and omega-3, there is a limitation on the conversion rate of ALA to both EPA and DHA. See pp 11-12.

    Regarding 8 -- Low dietary DHA may raise the conversion rate of ALA to DHA to such a degree that non-fish-eaters maintain as high a level of DHA in the plasma as fish eaters, and in the case of vegans, the DHA may be higher than in fish eaters.

    Regarding 9 -- Higher conversion rates for women than men, and regarding women of child bearing age -- While young men show EPA and DHA conversion rates of 8% and 4%, young women show rates of 21% and 9.2% (first cite figures)

    Regarding 10 -- Pregnant women provide more than 860 mg/week of umbilical DHA during late gestation, as this much has been measured to accumulate just in the infant brain, liver and adipose tissue but does not reflect accumulation in other tissue, even the eyes.

    Regarding 12 -- Though the mother's physiology selects the amount of DHA to pass to the placenta, the only fatty acids that are vary according to the mother's intake are EPA and total omega-6. See page 28 of the link. DHA that is endogenously derived by the mother does not vary the umbilical transfer according to the mother's intake of ALA. See page 12 of the link. That is, partitioning of DHA to the fetus is controlled, not proportional to ALA intake. Ingested and preformed DHA however may go to the fetus. There is some possibility that if there is insufficient circulating DHA in the mother, regardless of source, some DHA may be derived from organ or fat recycling.

    Regarding 13 -- Effect on IQ from DHA supplements in childhood -- often not significant

    Regarding 14 -- Breast milk DHA based on diet
    Ryan Mitovator, recoen and JanSz like this.
  2. Jack Kruse

    Jack Kruse Administrator

    1-3 % based on the literature.
  3. Jack Kruse

    Jack Kruse Administrator

  4. JanSz

    JanSz Gold

    Take into consideration half life of DHA

    supposedly it is very long

    Similarly EPA, if high, hard to get rid of it.

  5. Glenn A

    Glenn A New Member

    Thanks Dr. Kruse! Some amazing things in the Jama Opthamology Oct. 2016 Spanish study cited in your Medicalxpress article.

    Weaknesses in the study actually point to the fact that the effect of DHA (and not just ALA in total) from the sea food might actually be stronger than indicated in this substudy. Here's why:

    The study broke the results into just 2 categories: those eating greater than, versus those eating less than 500 mg/day of almost any kind of whole fish. This was a computed average based on 2 full servings of oily fish per week, not a daily fish intake. They might easily have had a more significant and glaring reduction in the incidence of sight-threatening diabetic retinopathy (DR) than the 48% they showed if they had had more separation in the amount of seafood ingested between the two groups of tested individuals that were selected to be reported on. Say, instead of just "less than a 500 mg/day average vs 500 mg or more per day average" they had compared "less than 300 mg/day average vs 500 mg/day average".

    Also, though the study covered individuals broken into 3 different diet groups, "Mediterranean diet + olive oil", "Mediterranean diet + nuts", and "control", the fact remains that the "control" diet was also a Mediterranean diet (taking place in Spain), thought to be higher in certain foods such as vegetables and fresh caught fish than diets in other countries in other areas that still happen to have patients routinely treated for DR. Since this study was looking at only one relationship, that of fish ingestion to DR, the fact that it was based on slight modifications to an essentially healthy diet may have diluted the effect of the fish on reducing DR. Such a study done in, say Memphis Tennessee might have shown a more substantial reduction in sight-threatening DR in diabetics who were on the fish-heavy diet.

    Another weakness of the study, this time not necessarily implying that the effect of seafood may be stronger than found in this study, is that the seafood that qualified by their criteria was not at all specified as omega-3 rich seafood, such as that from cold waters where fish content of ALA is much higher than Meditarranean seafood. Using only cold-water fish might have produced a better reduction in DR, but if there are factors in seafood, aside from the PUFA, that affect eye health (such as astaxanthin), then results may vary in either direction.

    So in spite of my complete agreement with the study which seems to prove that seafood may be an important part of diet that can have a great health benefit in terms of maintain eye health, I would love to see if other sources of ALA, in the same amounts as demonstrated effective in this study, can't be just as effective at reducing DR as is seafood. Specifically foods such as spinach, purslane, and walnuts which are rich in omega-3, but not excessive in omega-6. One thing this study did not consider is the known competition of omega-6 with omega-3 for enzymes and catalysts. Limiting excessive intake of omega-6 PUFA could, by itself, provide supplies of EPA and DHA from many diets that would exceed that amounts provided by an average of 500 mg of fish PUFA per day.

    Further, but along the same line, the study stopped at measuring only the omega-3 total in the fish, the ALA. Though it said "intake of at least 500 mg/d of eicosapentaenoic acid + DHA" (don't ask me why it abbreviated one and not the other), implying that each acid would be derived in total by the human body, you and I both know that only a fraction of each, (and less DHA than EPA) will be realized from the 500 mg/d average ingested from mediterranean fish. This brings up the point I made in the original post, that age matters. I believe their cohort averaged 67 years of age. From my studies, a 60 year old man (they used men in the study) derives a very small percent of the DHA present in fish, or even what is present in any vegetable's total ALA. Compared to a 60 year old, young men can derive twice as much DHA from ALA, and young women of child baring age can derive over 4 times as much DHA. Newborns may derive 10 times the DHA from the same foods as do aged men.

    So there's more in this study that is not clear than what is very clear. But the fact remains that fish (at least) due to (probably) PUFA content, helps a lot to prevent eye deterioration in aged, diabetic men. And the good news is, this report was merely a SUBSTUDY emphasizing part of the results obtained from the PREDIMED Trial, therefore, all the data is still there to make correlations of many other kinds. More may be gained from other substudies.
  6. Katie Durham

    Katie Durham New Member

    Very long under what conditions and in what locations? The way you phrase it DHA has a static half life. But we're taught here that blue light toxicity lowers DHA and the ability to regenerate through the Bazan effect, so the more blue light we're dealing with, the more seafood we should eat.
    Glenn A likes this.
  7. JanSz

    JanSz Gold

    When you eat seafood you are getting what it contains.
    It contains EPA and DHA.
    EPA content in any seafood is multiple times higher than in humans.
    Those who bother to do fatty acids analysis are finding excess of EPA and often excess of DHA in their blood.

    Many sick people,
    sick with neolithic diseases,
    are finding excess of DHA in their blood.
    Often extremely high excess.

    I posted some of those analyses in my earlier posts.

    Glenn A likes this.
  8. Glenn A

    Glenn A New Member

    True - What conditions? And I think JanSz is referring to short loop DHA when he says the half-life is supposedly very long. But as Jack says in


    if you get excess blue light hitting the retina, you are going to ruin the DHA that is in that long-life cycle SHORT LOOP, and need more introduced via the long loop, from the diet and via the liver.

    So yes, the more blue light you deal with, the more dietary omega-3 you need. I won't say it has to be fish, but I certainly won't say it should be supplements, for as JanSz says, people are often raising their DHA and EPA to pharmacologically damaging levels in the blood from blindly taking supplemental omega-3 oils.

    Another way to advise, instead of "the more blue light, the greater need for seafood", would be, "just always block nnEMF, especially the blues." I like this better because it doesn't give the impression that, say, eating fish, is a solution to subjecting oneself to high levels of non-native EMF. There's really no safe solution to that puzzle it seems to me. It's better to block man-made EMF and worry less about raising one's dose of DHA, especially if you are not testing for your levels. Right?

    I almost want to paraphrase Jack and say "Block the blue OR eat your seafood." I lean that way, but won't preach that yet.
  9. JanSz

    JanSz Gold

    For now,
    all I am saying
    address EPA when advising eating seafood for its DHA content.

    It is not only about excessive EPA
    it is also that
    excessive EPA or really excessive Omega-3 is highly suppressive of Omega-6, and (highly valuable) AA in particular.

    We need everything
    in right amounts.

    Last edited: Feb 7, 2019
    Glenn A likes this.
  10. Glenn A

    Glenn A New Member

    Oh, good points! Thanks.

    I am very used to hearing about the reverse, excess omega-6 restricting derivation of the omega-3's. I wasn't aware that the reverse could also happen, as most people ignorant of even the usefulness of PUFA are overdosing on omega-6 withtheir SAD diets. But yes, as you point out, when people start restricting their omega-6 input back to "naturally derived" proportions by changing to free-range or wild animal products and totally limiting consumption of commercial omega-6 oils found in junk food, pastries and PUFA cooking oils (as I've done of course). In that situation, all it might take would be to start an omega-3 supplement and one has the excess of omega-3 derivatives you are advising to avoid.

    So yes, just eat real food. The epi-paleo diet works.
    JanSz likes this.

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