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Thread: B12 intake for non-vegans

  1. #1
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    Question B12 intake for non-vegans

    From this ( http://www.alliance-natural-health.o...siteDoc_26.pdf ) pdf:

    "Detailed intake data on vitamin B12 in EU countries are scarce. Recently, average intakes of 4.9 and 3.9 g/day were reported for adult men and women, respectively, from a representative household survey in The Netherlands, using a two-day dietary record method
    (Blokdijk et al., 2000). The mean vitamin B12 intake in Dutch elderly subjects was about 5 g/day, with a range of 0.5-16.9 g/day from dietary intake, and up to 32 g/day for the total
    intake (including supplements) (van Asselt et al., 1998).
    Data from Ireland (IUNA, 2000) indicate a mean vitamin B12 intake from all sources (food + supplements) of 5.4 and 4.1 g/day for men and women, respectively. The upper 97.5th
    percentiles were 15.0 and 15.1 g/day, respectively. Mean intakes from food sources only were 5.2 and 3.6 g/day, for males and females, with upper 97.5th percentiles of 13.1 and 11.8 g/day, respectively.
    Data from the United Kingdom (HMSO, 1990) indicate a mean vitamin B12 intake from all sources (food + supplements) of 7.3 and 5.4 g/day for men and women, respectively. The upper 97.5th percentiles were 23.0 and 18.2 g/day, respectively. Mean intakes from food sources only were 7.2 and 5.2 g/day, for males and females, with upper 97.5th percentiles of
    22.9 and 17.8 g/day, respectively. Data from the Boston Nutritional Status Survey on vitamin B12 supplement use among elderly show that the median (percentile 50) intake from supplements is 5 g/day for males and 6 g/day for females (total intake from diet + supplement: 9.7 and 9.0g/day, respectively); the percentile 95 intake from supplements was 77 g/day in men and 100 g/day in women, and the corresponding values for total intake were 83 g/day in men and 106 g/day in women,
    respectively. Data from NHANES III (USA) give a highest mean intake from diet + supplements for males (31-50 years) of 17 g/day, the percentile 95 intake in pregnant females was 37 g/day (data taken from FNB DRI Report, IOM, 1998)."

    This study showed that the mean intake of B12 among female Japanese college students were v4.4. (+-.4.1) MU.g.

  2. #2
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    Two of my meat eating friends are suffering from b12 deficiency, and are having injections. But they are still eating meat!
    Eve

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    From http://www.nap.edu/openbook/0309065542/html/306.html:

    "Vitamin B12 (cobalamin) functions as a coenzyme for a critical methyl transfer reaction that converts homocysteine to methionine and for a separate reaction that converts L-methylmalonyl-coenzyme A (CoA) to succinyl-CoA. The Recommended Dietary Allowance (RDA) for vitamin B12 is based on the amount needed for the maintenance of hematological status and normal serum vitamin B12 values. An assumed absorption of 50 percent is included in the recommended intake. The RDA for adults is 2.4 g/ day of vitamin B12. Because 10 to 30 percent of older people may be unable to absorb naturally occurring vitamin B12, it is advisable for those older than 50 years to meet their RDA mainly by consuming foods fortified with vitamin B12 or a vitamin B12-containing supplement. Individuals with vitamin B12 deficiency caused by a lack of intrinsic factor require medical treatment. The median intake of vitamin B12 from food in the United States was estimated to be approximately 5 g/day for men and 3.5 g/day for women. The ninety-fifth percentile of vitamin B12 intake from both food and supplements was approximately 27 g/day. In one Canadian province the mean dietary intake was estimated to be approximately 7 g/day for men and 4 g/day for women. There is not sufficient scientific evidence to set a Tolerable Upper Intake Level (UL) for vitamin B12 at this time."
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

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    Default Re: What is the intake of B12 for non-vegans?

    According to www.food.gov.uk/multimedia/pdfs/EVM0020P.pdf :

    UK
    Average daily intakes from food and supplements for adults aged 16-64 years were 7.3 g for men and 5.4g for women in 1986/87. The contribution of dietary supplements to average intakes was small in all age groups.

    US
    13. The average dietary intake of vitamin B12 in adult men in the US in 1985 was 7.84 g/day. Corresponding intakes for adult women and children (1-5 years) were 4.85 and 3.80 g/day, respectively. However, reported levels of vitamin B12 in foods may have included 5-30% microbically active non-Cbl corrinoids (NRC, 1989)
    There's also some detailed info on average B12 levels in various age grouos here.

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    Default Re: What is the intake of B12 for non-vegans?

    When reading information about B12 intake among non-evgans (and vegans), remember that these number are normally based on measuring B12 levels in blood, and do not include tests of MMA and homocysteine levels, which is currently considered an effective way to check if the B12 measured in the body actually is active b12.

    I saw a study recently claiming that if MMA and homocysteine levels should be taken into consideration as well (when looking at serum B12 level), the number of people with acceptable B12 levels would be reduced by 50% (this was not referring to vegans).

    Furthermore, not only do non-vegans indirectly eat supplements when they eat animal products (because animals often are given supplements), but a study I've seen claim that 1/3 of all (non-vegan) people eat vitamin B supplements. According to another article, 'about half the country takes nutritional supplements'.

    The information about how many non-vegans that are low or deficient in B12 is also conflicting. Some studies say that circa 40% of non-vegans have B12 levels in the low and/or deficient range... several studies conclude that circa 10% of all non-vegans are B12 deficient. If we assume that the truth is somewhere between 10% and 40%, and assume for now that the correct number is 25% (10+40/2=25), this number would still both be based on B12 serum tests alone, and on a group of people of which a large percentage takes vitamin B supplements.

    As we know, too low levels of B12 is not a good thing. The most dramatic results of B12 deficiency is dementia, difficulties in walking, Alzheimer's disease and blindness. But since there's both a pretty common agreement that circa 10% of people on a standard diet are B12 deficient, and also that 10% of the population do not suffer from Alzheimer, blindness or have difficulties in walking, we know that B12 deficiency as such does not automatically lead to these severe problems.

    Of course we don't want to have so low B12 levels that we are close to the point where any kind of serious problems may occur, and we have no reasons to think that we are more safe than non-vegans when it comes to B12. It's the other way round - the B12 vitamin is one of the few nutrients we know that non-vegans have higher levels of than vegans.

    Another question is how meaningful it is to use meat eaters B12 intake as a reference for vegans, because we know that meat eaters have such a high intake of B12 that lots of the B12 they consume isn't actually used, but instead stored away in the body (mainly in the liver) for future use.

    Some people take daily B12 supplementation in amounts much higher than what almost all the so called expert think we need, and explain this by saying that they take extra, daily large amounts in order to build up a storage. But if they take B12 daily, and intend to continue doing this, why do they need that massive, extra storage?

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    Default Re: B12 intake for non-vegans

    Example 1, based on the assumption that 10% of non-vegans have been found to B12 deficient:

    First, if we don't insist that supplementation is all bogus, let's assume that the 30% of all people who take B12 supplements are in the 90% percentile that in this example are NOT B12 deficient. If we should compare vegans who don't take supplements, we should compare vegans who don't take supplements with non-vegans that don't take supplements. We don't know if those 30% of all people who take supplements would be B12 deficient if they wouldn't take supplements, but then again, not only do meat eaters also often eat fortified food, they also eat eg. chicken who are commonly given B12 - so a factory farm chicken as such could actually be considered B12 fortified 'food'.

    So - for this non-scientific thought experiment, let's say that those 30% of all people who take vitamin B supplements do it for a reason, and would have been deficient if they wouldn't have been taking this. That leaves us with 60% of all people who are not declared deficient. Since we know that the numbers of people who aren't considered B12 deficient people would 50% lower if MMA and homocysteine levels would be taken into consideration, the number of non-vegans that we know are not B12 deficient would be reduced from 60% to 30% (if we both take the fact that lots of these people take supplements and also takes the fact that normal tests of B12 levels in blood don't take MMA and homocysteine levels into consideration).

    Example 2, based on the assumption that 40% of non-vegans have been found to B12 deficient:
    This leaves us with 60% that aren't deficient. If we again remove the 30% that apparently take vitamin B supplementation, assuming that these belong to the non-deficient group, that leaves us with 30%. Since this number isn't based on measuring MMA and homocysteine levels, and since it has been found that the number of people who are not deficient would have been 50% lower if MMA and Hcy would be taken into consideration, this means that - based on this unscientific experiment with numbers - there are only 15% of all people that are not B12 deficient if MMA and homocysteine should be taken into consideration.

    It's a kind of silly experiment with numbers, I know, but I think it's easy to forget that when we look at the number of non-vegans that aren't B12 deficient, we should use the same standards as we would use to find out how likely it is that a non-vegan would become deficient, and this means both looking at people who don't take supplementation and including the MMA/homocysteine aspect.

    Another thing is that the reference value defined by some vegans - 9-10 mcg B12/day is much higher than almost all other reference values out there, which normally are 2-3 mcg. This number (often 2, 2.4 or 3 mcg) is taking th fact that not all B12 we eat is being absorbed, and also that the number should be valid for 'almost everybody').

    The different reference values are important to have in mind if you read about B12 levels in food, because if we assume that we need 3-4-5 times the amount if B12 as most others think we need, and read about the possible B12 level in food or supplements, they'll all look very low.


    Maybe the reference values need to be updated. The jury is out on the link between homocysteine and heart disease, and B12 is linked to homocysteine levels. Maybe the reference values haven even taken all the B12 reducing factors when the standards have been set. But: if the the reference values should be doubled, tripled or more, the number of non-vegans that would show up as not getting enough B12 would also be increased dramatically in these threads.

    What we know today, is that most meat eaters hardly think of the fact that they are often eating vitamin fortified chicken or other fortified animal products - and we know that MMA and homocysteine levels normally are not taken into consideration when referring to the level of B12 in blood tests for 'all people'. It's even more complicated than that... more later.

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    Default Re: B12 intake for non-vegans

    Here's a Japanese study showing the amount of various vitamins in breast milk (pr 100 ml):
    The mean contents of each component were as follows: vitamin A, 159.0.+-.95.2IU/100mL; vitamin E, 0.325.+-.0.165.ALPHA.-TE mg/100mL; vitamin D3 (cholecalciferol), 8.0.+-.10.7ng/100mL; vitamin B1 (thiamin), 12.3.+-.3.2.MU.g/100mL; vitamin B2, 38.4.+-.12.7.MU.g/100mL; vitamin B6, 5.7.+-.2.5.MU.g/100mL; vitamin B12, 0.04.+-.0.02.MU.g/100mL; vitamin C, 5.1.+-.1.9mg/100mL; biotin, 0.50.+-.0.23.MU.g/100mL; choline, 9.2.+-.1.8mg/100mL; folic acid, 6.2.+-.2.9.MU.g/100mL; inositol, 12.6.+-.3.6mg/100mL; niacin (nicotinamide), 32.9.+-.20.4.MU.g/100mL and pantothenic acid, 0.27.+-.0.09mg/100mL.

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    Ex-admin Korn's Avatar
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    Default Re: B12 intake for non-vegans

    From http://ods.od.nih.gov/factsheets/Vit...hProfessional/

    Data from the 1999–2000 NHANES indicate that the median daily intake of vitamin B12 for the U.S. population is 3.4 mcg.
    Their source is here: http://www.cdc.gov/nchs/data/ad/ad339.pdf

    As usual, note that intake and absorption are two different things.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

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    Default Re: B12 intake for non-vegans

    From Vitamin B12 Sources and Bioavailability:
    The bioavailability of vitamin B12 in healthy humans from fish meat, sheep meat, and chicken meat averaged 42%, 56%–89%, and 61%–66%, respectively.
    This (again) confirms that even if the intake of B12 for meat eaters is around 5 mcg, not all the B12 they consume is absorbed.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

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    Default Re: B12 intake for non-vegans

    Here, in one 20 year old report suggesting that B12 from algae may not be bioavailable, the reference method used is to monitor mean corpuscular volume (MCV, the average red blood cell volume):

    The effect of algae (nori and spirulina) and fermented plant foods on the hematological status of vitamin B-12-deficient children was evaluated. Although rising plasma vitamin B-12 concentrations in children consuming only plant foods (0.1-2.7 micrograms vitamin B-12/d) indicated that the vitamin B-12 was absorbed, elevated baseline values of mean corpuscular volume (MCV) further deteriorated.
    (The change was very minor; only from 85 to 87, and without any intake of active B12, the change would probably have been more significant after one and a half months.)

    In contrast, MCV improved in children receiving fish containing 0.15-0.5 microgram vitamin B-12/d or a vitamin B-12 supplement. Further studies on the specificity of current vitamin B-12 assays are warranted. It seems unjustified to advocate algae and other plant foods as a safe source of vitamin B-12 because its bioavailability is questionable.
    Now, using MCV as the only reference for B12 bioactivity is questionable, but I'm posting this to mention that the intake of B12 from fish was 0.15-0.5 microgram per day. As suggested in the post above, 42% of the B12 from fish is considered bioavailable. This means that as little as 0.14 mcg B12 may have been consumed from fish.

    But this study contain lots of variables. Subject 6 (in the fish group) had their algae as their main B12 source, but saw both a B12 increase in plasma and MCV improvements. There were big variations in total B12 intake (from 2.7 mcg/day to 0.1 mcg/day). Two subject were tested for as much as 5 months, while others were tested for as little as one or one and a half month. The study don't seem to differentiate between fresh ad dried nori. Two of the five members of the vegan group used spirulina in addition to nori, now known to contain mainly inactive B12 analogues, and one of the vegan subjects had as low intake as 0.1 mcg B12/day.... and so on. This is a study which is often referred to, but it's far from an ideal collection of information, and the results aren't listed on a per-month basis, which would have made more sense.





    Dagniele suggested that as little as 0.2 to 0.3 mcg B12/day would improve MCV status, and referred to a study showing that as little as 0.1 mcg/day of B12 can lead to a 'full therapeutic response' in 1 month, but a newer study (measuring MMA levels) suggests that 0.3 mcg/day for 6-16 months infants are probably not enough to prevent B12 deficiency.) OTOH - the book 'Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998)' suggests that the average intake for 0-6 month old infants actually is 0.33 mcg/day. So - either are all 0-6 months infants B12 deficient, or one of these estimates are wrong.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

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