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Thread: B12 overdose / megadose?

  1. #51
    Pascale's Avatar
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    Default B12 Megadose?

    Are B12 megadoses (like in those b12 lozenges with 1 mg) safe to use for an extended period of time?
    Last edited by Korn; Oct 18th, 2006 at 05:48 PM. Reason: This was the first post in a similar thread....

  2. #52
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    Default Re: B12 Megadose?

    I have no idea but I do know that taking a lot of B12 makes me feel very nauseous.
    Peace, love, and happiness.

  3. #53
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    Default Re: B12 Megadose?

    Quote Tigerlily View Post
    I have no idea but I do know that taking a lot of B12 makes me feel very nauseous.
    AHHH! Ok I was going to post a thread about being nauseous, and I wonder if it is because I have been taking b12 supplements and eating foods that contain it.

    All evening I have been sick on my stomach with a severe migraine.
    Is b12 doing this to me or something else?

  4. #54
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    Default Re: B12 Megadose?

    Quote yasha View Post
    AHHH! Ok I was going to post a thread about being nauseous, and I wonder if it is because I have been taking b12 supplements and eating foods that contain it.

    All evening I have been sick on my stomach with a severe migraine.
    Is b12 doing this to me or something else?
    Have you always suffered from migraines?

    What dose B12 have you been taking?

    There is no need for megadoses unless you need to correct a deficinecy. The more B12 you take the less efficently your body absorbs it.

    Cheers

    Mike

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    Default Re: B12 Megadose?

    Quote yasha View Post
    AHHH! Ok I was going to post a thread about being nauseous, and I wonder if it is because I have been taking b12 supplements and eating foods that contain it.

    All evening I have been sick on my stomach with a severe migraine.
    Is b12 doing this to me or something else?
    I can't even take multi vitamins without breaking them in half. Next time I go vitamin shopping, I'm getting a kiddy formula.
    Peace, love, and happiness.

  6. #56
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    Default Re: B12 overdose / megadose?

    Me too, but I can take them with vinegar pretty good.
    it is wrong for a man to eat anything that causes someone else to stumble

  7. #57
    vegan pizza! thecatspajamas1's Avatar
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    Default Re: B12 overdose / megadose?

    The B vitamins (as well as C) are water soluble, so if you take too much you will pee it out and so theyre not as toxic as the fat soluble vitamins A,D,E, and K.
    I eat nutritional yeast by the spoonful.

  8. #58
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    The B vitamins (as well as C) are water soluble, so if you take too much you will pee it out and so theyre not as toxic as the fat soluble vitamins A,D,E, and K.
    Hmm... if all B12 that was 'too much' would be thrown away by the body, how would B12 overdose symptoms actually exist - and how could B12 be stored in the body for years?

  9. #59
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    Default Re: B12 overdose / megadose?

    Quote Korn View Post
    Hmm... if all B12 that was 'too much' would be thrown away by the body, how would B12 overdose symptoms actually exist - and how could B12 be stored in the body for years?
    I've been wondering that too- how it can be stored in the body. But what we've been learning in nutrition class is that its excreted with water, so I thought I should add that.
    I eat nutritional yeast by the spoonful.

  10. #60
    zzippffizz
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    Default Re: B12 overdose / megadose?

    I've been drinking an effervescent energy drink called Zipfizz everyday for a while now. Usually I only have one. Yesterday, i thought it would be exciting to have 6. ((sometimes I like to perform experiments on myself. don't judge me)) Then I looked at the nutrition information. 1 test tube full has 41,667% RDA of Vit B12 as well as 833% RDA of Vit C and caffeine from guarana seed, L-Taurine, etc. I have since developed a rash on my chest, neck, lower scalp and the sides of my torso under my rib cage. I was in class after consuming the 5th test tube. I felt like I was in a dream, sort of. Not drunk/high, but disconnected, ungrounded. It minimally impeded my mental function. I had no trouble taking tests but wasn't always able to follow what people were saying because I felt tired and awake at the same time. I also experienced a Niacin-like burning on the back of my neck and lower scalp. After the 3rd, it was able to sleep during the night. After the 6th, I was not able to nap. After the 4th, I began to feel sad and somewhat anxious. If I had been by myself, I probably would have cried, but I was at school. My blood pressure felt like it might have been high, but I don't own a pocket blood pressure tester so I can't say if it was for sure. Today I decided to check for information about B12 overdose and found this site, after the rash appeared last night. Sorry it's hard to follow the timeline of when I ingested the different doses, but I didn't feel motivated to type it out. If you're curious about any other side effects, feel free to ask.

  11. #61
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    1 test tube full has 41,667% RDA of Vit B12

    And you took five of these?? Ooops...

    In some European countries, more than 9 mcg B12 pr. day is considered medical treatment, and can't be bought without a doctor's prescription, and the amount of B12 you consumed is at least 500 times higher than that. If I were you, I'd stay away from anything containing B12 for a while!
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

  12. #62
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    There may ne no reliable, detailed studies on the link between high levels of B12 and cancer yet, but here's a link I came across by accident, more or less related to that topic. Cancer is defined as uncontrolled immature cell division. This URL is about a product called Trimethylaminohydroxybicycloheptane Chloride, or 714X.


    Here's what they write about 714X and B12:

    714X is a non-toxic treatment which supports the body's natural defense mechanisms. It is compatible with most therapeutic approaches seeking to bolster the biological terrain. These therapies are generally referred to as non-conventional, complimentary, alternative, etc.

    Clinical observations have revealed certain exceptions in the case of :
    Vitamin B-12
    Vitamin E
    Shark and bovine cartilage as well as other antiangiogenic products.

    These exceptions apply to dietary supplements but do not include vitamins B-12 and E found in food.

    Vitamin B12

    It is recommended not to simultaneously use 714X and vitamin B12 supplements.

    Vitamin B12 accelerates cellular division (especially blood cells) without distinguishing healthy cells from immature cells. There is nothing to be gained by stimulating cell division in an already hyperactive organism. This restriction does not affect vitamin B12's properties in a normal context.

    For those persons having had a partial or total removal of the small intestine who wish to take 714X, the above exception concerning vitamin B12 does not apply as this vitamin is essential for such persons' survival.
    I think the warning is very vague: First they write that 'It is recommended not to simultaneously use 714X and vitamin B12 supplements' and then that 'there is nothing to be gained by stimulating cell division in an already hyperactive organism'. But the most interesting part is this one: 'Vitamin B12 accelerates cellular division (especially blood cells) without distinguishing healthy cells from immature cells'. I've mentioned warning from doctors against taking B12 for people who have cancer (or are on their way to develop cancer) in a couple of other posts, and this URL confirms that B12 stimulates cell division (cancer= exaggerated cell division), and that B12 isn't able to distinguish between healthy and immature cells.

    According to this link, reports predict that four in every ten people in Britain will develop cancer at some point in their lives. The article also mention that Britain has one of the worst survival rates for cancer in the developed world, but IF we should apply those numbers on the members of this forum, 1600 of us should develop cancer at some point in our lives. Realistically, such studies (when/if they are correct) tells us that a lot of people are in a situation where they may or may not develop cancer, based on a lot of things they may or may not do something with.

    There are only a few studies that confirm a link between cancer and high B12 levels (see earlier posts in this thread), but in spite of not having hundreds of studies suggesting or confirming such a link, eating a too much of a substance that stimulates cell division, but can't distinguish between healthy and other cells doesn't sound like a terrific idea to me.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

  13. #63
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    From http://www.acu-cell.com/nico.html :
    Some uninformed practitioners believe that there is no overdose possible with Vitamin B12, however
    5-10% of the population presents with above-normal levels of Vit B12, so if injections are erroneously
    given, they can trigger a number of adverse symptoms that may include coronary artery spasms with
    chest pains, numbness or pain down their right arm, and/or TIA-like symptoms with tingling / numbness
    on the right side of the face.
    There is also a risk of hypokalemia, pulmonary edema, peripheral vascular thrombosis, optic nerve
    atrophy for someone with Leber's disease, and others. Risks from intranasal use of Vitamin B12
    include glossitis, headache, sore throat, rhinitis, and feeling of "pins and needles." Individuals suffering
    from Mitral Valve Prolapse (MVP) are also vulnerable to experience a worsening, or an acute flare-up
    of MVP symptoms following a Vitamin B12 shot if not indicated.

    Even without having had any Vitamin B12 injections, individuals who run naturally high Vitamin B12
    and cobalt levels (which may include patients with mitral valve prolapse), tend to frequently suffer from
    tachycardia, panic-anxiety attacks, or angina-like chest pains, that may be accompanied by numbness
    and tingling in the face or extremities.
    In contrast to cellular measurements, blood tests for cobalt or Vitamin B12 levels (including the Schilling
    test) are not only very unreliable, but at times alarmingly wrong, subjecting patients to improper therapy,
    or routinely misdiagnosing them as Psychiatric Cases, when in fact correcting their abnormal cobalt,
    Vitamin B12 and nickel status (or ratios) could resolve the problem.
    Getting too much B12/cobalt from a vegan diet is NOT a problem, but people who supplements too much with B12 in order to be 'on the safe side' may experience some of the overdose symptoms described above.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

  14. #64
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    From http://www.angelhealingcenter.com/AmalgamProtocol.html :

    14. B Complex: Should provide at least 15-25 milligrams of each of the various B vitamins. Take the number of tablets indicated to provide the desired amounts. [NOTE; A word of caution concerning those individuals taking large amounts or injections of vitamin B12. There is limited scientific information indicating that vitamin B12 can methylate mercury. Consequently, during the entire amalgam replacement process, every effort should be made to eliminate excess B12 intake. If you must receive B12 injections, request your physician to use hydroxocobalamin.]
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

  15. #65
    nervine
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    Default Re: B12 Megadose?

    Quote Pascale View Post
    Are B12 megadoses (like in those b12 lozenges with 1 mg) safe to use for an extended period of time?
    I just bought a packet of something like that too. It's together with Natrium Chloride. I plan on taking them once or twice a month..

  16. #66
    ella_vega
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    Default Re: B12 overdose / megadose?

    hi korn.

    very inteesting issue.

    i will follow the thread.

  17. #67
    Michael Benis's Avatar
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    Default Re: B12 overdose / megadose?

    Quote Korn View Post
    Getting too much B12/cobalt from a vegan diet is NOT a problem, but people who supplements too much with B12 in order to be 'on the safe side' may experience some of the overdose symptoms described above.
    I'd caution everyone to read Korn's words carefully. What's important is the "too much". The Vegan Society recommends either eating foods containing synthesised B12 or supplementing with it. Supplementation to be on the safe side is responsible for vegans, both for our own health and to be effective advocates for a vegan diet. Taking very high levels of supplements for a long time without supervision/tests is obviously not responsible.

    Unfortunately the site cited () by Korn (and it is a commercial site) does not state any of the sources of its information. However it appears that the part about "naturally high levels" is the author's own conclusion as far as I can gather. The studies/papers referred to seem to have been about the inappropriate use of high injected doses of B12.

    Please don't use this as a reason not to supplement. Several vegan pioneers suffered greatly from B12 deficiency. There's not excuse for us to waste their efforts.

    Cheers

    Mike

  18. #68
    Ex-admin Korn's Avatar
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    Default B12 comments

    What's important is the "too much".
    Yes, that's important. OTOH, if someone goes vegan today, they may already B12 levels way above the average population, and too high levels of B12 is - according to various sources - associated with health problems. Ohters seem to suggest that one can never get too much B12.

    Supplementation to be on the safe side is responsible for vegans.
    But then again - you're not necessarily on the safe side if you take supplements. Giving such an advice can create a several false illusions, for example that (if B12 analogues actually is a real problem) that supplements or fortified food always contain bioactive B12 and no B12 analogues, or that everybody who takes supplements can absorb the supplements they take, or that persons who are exposed to more 'B12 killers' than the average population is just as 'safe' on x mcg B12 daily as someone who are exposed to an 'average' amount of B12 destroying factors.

    We have circa 6000 members here, and if it's correct that 1% of all people (vegans included) have a B12 absorption problem, that alone would mean that 60 of our members could develop severe B12 deficiency based on absorption problems alone (problem that has nothing to do with their vegan diet) - if we would have given advice a la 'take supplements and you're safe'.

    There are lots of meat eaters out there, and while we know that lots of them are short in folate, Omega-3 and many other nutrients, between 10 and 40% of them also have low B12 levels. Meat eaters normally consume 'enough' B12, and I won't contribute to all the simplification around B12 that both some vegans and non-vegans do. Your B12 status is about a lot more than how much B12 you consume, and to inform about this is important.

    Vegans are obviously concerned with which nutrients that needs special attention for vegans, but if both vegans and non-vegans keep talking about which nutrients vegans need to pay extra attention to, and never inform about the fact that non-vegans also have a lot of nutrients that probably are very low or even deficient in, the information is unbalanced, and will give a wrong picture of the healthiness of living on a plant based diet.


    There are vegans who have had too low B2 levels, and based on studies that show that 10-40% of non-vegans have low B12 levels as well, there are between 6 and 24 million people in UK alone with low B12 levels - and most of these (95%?) are not vegans. Of course there are vegans with B12 deficiency, and there should more vegans, percentwise, than non-vegans with B12 deficiency, because vegans have other nutrients they need to pat extra attention to than non-vegans, and B12 is the main think to look out for for vegans. There's reason not to pay attention to B12 levels for vegans, and it doesn't help a B12-deficient vegan much to know that non-vegans are deficient in a number of nutrients...

  19. #69
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    Default Re: B12 overdose / megadose?

    Korn, sure there are lots of variables, but let's cut to the chase: Are you changing your previous advice and not recommending vegans to take a B12 supplement at the lower (RDA) levels?

  20. #70
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Are you changing your previous advice and not recommending vegans to take a B12 supplement at the lower (RDA) levels?

    I'm not 100% sure about what you mean by 'take a B12 supplement at the lower (RDA) levels', but (of course) I don't think anyone should have too low levels of anything, and that if they do, they should so something about it.

    I'm also saying that...

    • Both vegans and non-vegans may need to take supplements. It seems that non-vegans need to worry about more nutrients than vegans, but when it comes to B12 specifically, a vegan is more likely to develop a B12 deficiency than a non-vegan (the opposite is true for other nutrients).

    • If you miss a nutrient, taking a pill containing that nutrient may solve the problem - but not always. Due to potential absorption problems and other reasons, there's no such thing as 'take a pill and you're safe' for everybody.

    • Getting enough B12 isn't only about your B12 intake, which is why a general advice saying 'take a pill' may be either useful or cause harm, depending on the person who is receiving this advice.

    • Just like high levels of folate can 'mask' low levels of B12 (in the sense that a starting B12 deficiency may not be discovered at an early stage), compensating for an unhealthy lifestyle by eating a lot of supplements may also 'mask' the fact that your lifestyle (total food/drink intake - plus lack of sunlight/fresh air and exercise) is the problem, it's not the lack of taking supplements.

    • If a person needs to take a nutrient supplement, she needs to remember that the amount she needs to consume varies from person to person. Giving advice that's trying to simplify the situation may complicate the situation.

    Example: Some people may think they eat enough plants if they follow the advice about eating '5 a day', but that advice is extremely over-simplified, and may create a false illusion that they're getting the antioxidants, phyto-chemicals, fiber, folate etc. they need. Some people give a similar kind of advice about B12.

    • Let's say it's 500,000 vegans in a country, and that 50% of those vegas take B12 supplements. That's 250,000 vegans who don't take a B12 supplement (there may be other people living on a vegan diet as well, like vegetarians with milk allergy or lactose intolerance, but let's ignore them for now). If it's right that 1% of these 250,000 have a B12 absorption problem (which has nothing to do with their vegan diet), that's 2500 vegans in that country who should develop serious B12 deficiency symptoms. Two thousand five hundred! So... the 'I know some long time vegans who had B12 deficiency'-"argument" agaisnt going vegan is totally non-valid, because in any group of this size (vegans or non-vegans), based on the numbers above, there should be 2-3000 people with a serious B12 deficiency anyway within this group, even if half of these people took daily B12 supplements.

    • There's no reason to use any of these numbers as an excuse for ignoring the fact that B12 is one of the nutrients that vegans need to pay extra attention to. Unhealthy vegans is bad marketing for veganism, and even if many people eat vegan for health reasons alone, others/vegan newbies may think that vegan food isn't as healthy as non-vegan food. By staying healthy more people will understand that vegan food is healthy.

    The median intake of vitamin B12 from food for non-vegans is estimated to ca. 5 mcg/day. (The RDA for B12 is normally around 2.4 mcg). At least one vegan site suggests that vegans should take 10 mcg daily four times the RDA, and twice the average B12 intake for omnivores - even if absorbing B12 from supplements (if taken the 'right' way) may be more efficient than absorbing it from food (due to the difference in the protein binding). This is probably based on the idea that increasing homocysteine levels always is good for your heart, but there is still disagreement about this, and even if it is right that increasing the homocysteine levels always is good for your heart, I'm against any kind of nutrient information that - while it is meant in a helpful and positive way - gives the impression that vegans, unlike non-vegans won't get enough of the nutrients they need and therefore - again, unlike non-vegans - have to take supplements.

    When there is disagreements among health professionals about important certain issues, it's better to inform about these disagreements than to decide what you mean, promote your opinion and not mention that there are others who are having opposite views.

    I'm happy to continue this discussion (about supplements and what kind of advice that makes sense to give to vegans about B12), but let's do it in another thread, OK?

  21. #71
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Here are some more links about B12 overdosing:

    http://www.iscid.org/encyclopedia/Vitamin_B12:
    It is possible to overdose on vitamin B12; negative effects include cardiovascular, dermatologic, gastrointestinal, and hematological problems.
    "Nutrition for Vegetarians" by Drs. Agatha and Calvin Trash:
    "In animals studies, there have been cases of increased cancer production in animals receiving high levels of B-12. It has been noted that the animals have an increased production of white blood cells such as occurs in chronic myelogenous leukemia. A case has been reported of acute myeloblastic leukemia resulting from B-12 overdose in the treatment of pernicious anemia."
    http://www.newswise.com/articles/view/513540/
    These days, most health warnings about vitamins focus on the danger of overdose. For vitamin B12, though, it's more likely that people are getting too little. In fact, B12 deficiency is the most common nutritional deficiency in the developing world and possibly in the United States as well.
    http://online-vitamin-info.com/vitamin_b12.html
    Although very rare, a vitamin B12 overdose can result in some forms of anemia, hyperthyroid condition, tingling or numbness in arm or face, anxiety, panic attacks, insomnia and heart palpitations among other conditions. If you have been taking large quantities and experience these problems, cut back on your intake. Medical treatment should not be required for vitamin B12 overdose if you exercise moderation and common sense.

    http://www.essential-vitamin-supplem...upplement.html
    Here are some of the most common problems or ailments of low vitamin B12 levels:

    – Loss of appetite
    – Growth deficiencies in children
    – Excessive tiredness
    – Brain damage
    – Neuritis
    – Nervousness
    – Spinal cord degeneration
    – Feelings of depression
    – Weakness and dizziness
    – Tingling or numbness in the extremities

    Vitamin B12 deficiency causes neural tube defects during pregnancy. Vitamin B12 supplement or a vitamin B12 rich diet is highly advisable for adults over 50. Vitamin B12 supplement overdose does not generally pose much of a danger.
    http://health.yahoo.com/drug/d00413a1:
    What happens if I overdose?

    An overdose of cyanocobalamin is unlikely to threaten life. Call your doctor, an emergency room, or a poison control center for advice if you suspect an overdose.

    Symptoms of a cyanocobalamin overdose are not known.
    ...and then, on the same page:
    If you experience any of the following serious side effects, stop taking cyanocobalamin and seek emergency medical attention:
    an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
    chest pain or difficulty breathing; or
    unusual warmth, redness, or pain in an arm or leg.
    Other less serious side effects may be more likely to occur. Continue to take cyanocobalamin and talk to your doctor if you experience

    headache;
    upset stomach or diarrhea;
    numbness or tingling;
    fever;
    dizziness;
    felling of swelling of entire body; or
    itching or rash.
    Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
    http://ods.od.nih.gov/factsheets/vitaminb12.asp
    What is the health risk of too much vitamin B12?

    The Institute of Medicine of the National Academies did not establish a UL for this vitamin because vitamin B12 has a very low potential for toxicity. The IOM states that "no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals" [7]. In fact, the IOM recommends that adults older than 50 years get most of their vitamin B12 from vitamin supplements or fortified food because of the high incidence of impaired absorption in this age group of vitamin B12 from foods that come from animals [7].
    http://www.webmd.com/drugs/drug-6035...&pagenumber=6:
    Aca B-12 Inj
    Back to Drug Overview
    Does this medication have side effects?
    The following side effects are associated with Aca B-12 Inj:
    Infrequent side effects:
    Itching Less Severe
    Diarrhea Less Severe
    Rare side effects:
    Life Threatening Allergic Reaction Severe
    http://www.drugs.com/mtm/b-12-resin.html
    What happens if I overdose?
    Seek emergency medical attention if you think you have used too much of this medicine. An overdose of cyanocobalamin is not likely to cause life-threatening symptoms.
    [...]
    B-12 Resin (cyanocobalamin) side effects
    Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using cyanocobalamin and call your doctor at once if you have any of these serious side effects:
    chest pain or difficulty breathing; or
    unusual warmth, redness, or pain in an arm or leg.
    Less serious side effects may include:
    headache or dizziness;
    upset stomach or diarrhea;
    numbness or tingling;
    fever;
    joint pain;
    stuffy or runny nose, sore throat, nasal pain;
    swelling; or
    itching or rash.
    This list is not complete and other side effects may occur. Tell your doctor about any unusual or bothersome side effect
    .


    http://vitamins-nutrition.org/vitami...cobalamin.html
    Overdose:
    Signs of Overdose:
    When taken in conjunction with large doses of vitamin C, nosebleeds, ear bleeding, or dry mouth may occur.
    Side Effects:
    Reaction or effect : What to do
    Diarrhea : Stop use and call doctor.
    Skin itching : Obtain emergency treatment immediately
    http://www.vitamindeals.info/articles/vitamin-b12.html
    What Happens If You Get Too Much Vitamin B12?
    Symptoms of a B12 overdose are unknown. There is no sufficient, reliable information about the safety of very large amounts.
    ...and finally, for pure entertainment purposes, from syl.com, a dating service site:
    http://www.syl.com/hb/toomuchofagood...itaminb12.html
    During World War II, vitamin B12 was given to soldiers before a battle. It was noticed that workers, who were given the vitamin B12, looked calmer. By 1937 manufacturers enriched flour with the vitamin B12. The Medical Institute says that the overdose of vitamin B12 with food doesn't influence the human body in a bad way. The vitamin B12 side effects are very seldom. But they appear when a person suffers from any chronicle disease.
    World War 2 ended in 1945. B12 was discovered in 1948.

  22. #72
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    From http://www.cqs.com/amalgam.htm

    15. Methyl mercury is more toxic to some body processes than inorganic mercury. Mercury from amalgam is methylated by bacteria and candida albicans in the mouth and intestines(51,81,98,182,225). Oral bacteria streptococommus mitior,S.mutans, and S.sanguis were all found to methylate mercury(81). High levels of Vit B12 in the system also have been found to result in increased methyl mercury concentrations in the liver and brain(51). Methyl mercury is 10 times more potent in causing genetic damage than any other known chemical (Ramel, in(35)), and also crosses the blood-brain barrier readily. Once mercury vapor or methyl mercury are converted to inorganic mercury in cells or the brain, the mercury does not readily cross cell membranes or the blood-brain barrier. Thus mercury has a very long half life in the brain. N-acetylcysteine(NAC) has been found to be effective at increasing glutathione levels and chelating methyl mercury(54,126).

  23. #73
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    B12 has several functions, some of them related to cell division and cell growth. Cancer is caused by abnormal and uncontrolled cell division.

    Now, findings about what may be beneficial for cancer patients may not at all be valid for others, but here's a study confirming the effect B12 has on cancer cells:

    We have demonstrated for the first time that the simple depletion of vitamin B12 - an essential enzyme co-factor for cell proliferation, can trigger programmed cell death in cancer cells without exposure to toxic chemotherapeutic drugs or radiation," said Dr. A. Charles Morgan, Jr., Ph.D., president and chief technical officer of Receptagen.

    Receptagen's therapeutic approach involves growth blocker drugs designed to selectively deplete cancer cells of vitamin B12, an essential nutrient for cell growth and division. Vitamin B12 depletion is a treatment approach that has been used to successfully treat patients with acute leukemia. But until now, drugs capable of B12 depletion have not been in existence.
    So - B12 doesn't only stimulate normal growth in children, it's essential for cancer cell survival as well.

    Again - this isn't an argument for a B12 depleted 'lifestyle', but since cancer is presently responsible for about 25% of all deaths in US and other so called 'developed' countries, maybe it's worth thinking of the possible side effect too high B12 levels can have - not only for people with a cancer diagnosis, but for the millions of people who will develop cancer in the future but don't know it yet.

    Some people claim that one cannot take too much B12, but IMO we should look at all the possible effects of too much B12, not only intoxication as a result of overdosing B12, but also possible side effects and on health issues associated with high B12 levels. If you google 'vegan' and 'cancer', you'll find a lot of info confirming that vegans are less likely will develop certain types of cancer than 'normal' people, and as we know, vegans normally have lower levels of B12 than non-vegans (often too low, which of course isn't good either).

  24. #74
    Michael Benis's Avatar
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    Default Re: B12 overdose / megadose?

    It's essential for lots of groth and maintenance process and a deificinecy can slow these. Sure. So?

    Anyonetaking in more B12 than they need within levles not induced by massive oversupplmewntation will simply store the excess. It will not alter tissue levels of B12.

  25. #75
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    It will not alter tissue levels of B12.
    B12 mainly is stores in muscles and liver, and since 'tissue' is often used about muscle/liver ('muscle tissue', 'liver tissue'), I don't think I understand what you mean....? Here's one article discussing B12 levels in liver tissue: The Vitamin B12 Content of Human Liver Tissue and Its Nutritional Significance The fact that so many people carry around so high B12 amounts in their liver that it could be used as a B12 reserve for years to come somewhat suggests that they consume way too much B12. This, combined with the fact that so many people (meat eaters) who live on a diet that as such isn't B12 deficient also are very low in B12 suggests the amount of B12 humans consume only represent one (possibly overrated) factor in terms of what actually matters when it comes to maintaining a healthy level of B12.


    Anyway, here's some more info about B12 allergy (which is rare):
    Allergy to hydroxycobalamin, with tolerance of cyanocobalamin

  26. #76
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    Default Re: B12 overdose / megadose?

    Today I received my blood test results and I have what seems like an enormously high level of B12. Normal range 145 - 180 pg/ml
    My level is 239
    Should I stop taking the Veg1 supplement do you think? I'm freaking out a bit because it seems that high B12 is associated with some illnesses.
    Also my ferretin level has gone down from 50 ng/ml in the last year to 29 ng/ml Normal range between 15 - 160ng/ml.
    I have called the Vegan Soc. who didn't have anybody who could give detailed advice. I would be so grateful if anybody could help me!! Thankyou.

  27. #77
    Michael Benis's Avatar
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    Default Re: B12 overdose / megadose?

    Korn you can have normal or high serum (blood) levels of B12 but low tissue levels (i.e. be deficient). This is, for example, common in alcoholics.

    In other words, "normal" B12 blood levels do not always indicate a lack of B12 deficiency.

    hth

    Mike

  28. #78
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Quote Michael Benis View Post
    Korn you can have normal or high serum (blood) levels of B12 but low tissue levels (i.e. be deficient).
    Sure - my point was that if you overdose on B12, the body is capable of storing B12 - in the tissues.... but never mind.

    In other words, "normal" B12 blood levels do not always indicate a lack of B12 deficiency.
    Sure.

    The last numbers I heard was that 50% of the people who have 'normal' B12 blood levels actually don't actually have sufficient levels of active B12 (this was a study on the average population, and not a vegan specific study).

  29. #79
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    Default Re: B12 overdose / megadose?

    Well that's another point - suggesting apart form anything else that the word overdose may not be that appropriate....

  30. #80
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    Default Re: B12 overdose / megadose?

    I agree that nuances are important, 'megadose' is often a more relevant word than overdose, and there's also a huge difference between 'problems associated with overdose/megadose', 'allergic reactions', 'toxic reactions' or 'health problems associated with high B12 intake', or 'health problems associated with living on a diet with a higher amount of B12 than a vegan diet'...

    As this thread grows longer, we probably should divide it into separate threads for overdose / generally high B12 intake / allergic reactions etc.

  31. #81
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Quote auntierozzi View Post
    Today I received my blood test results and I have what seems like an enormously high level of B12. Normal range 145 - 180 pg/ml
    My level is 239"
    If you look at the references used in this new thread, you'll see that below 259 is considered the 'low normal range'...


    Should I stop taking the Veg1 supplement do you think? I'm freaking out a bit because it seems that high B12 is associated with some illnesses.
    If you read this thread only, it may seem that B12 overdosing is generally a more serious problem than not getting enough B12, but that's not the case - it's normally the other way round. I started this thread more or less as a comment to those who more or less assume we can never get too much B12... some of these take 100 times the needed B12 amounts daily - or more.

  32. #82
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Here's something that looks like a perfect example of the kind of information we're not looking for. If you click on Free Instant Access" (no email needed), you'll find stuff like "I am out to help you cure your depression, once and for all, without using drugs like vitamin b12, which will undoubtedly turn you into a zombie". Why don't these salesmen get that people do not trust sites that claim that they can cure stuff in three minutes and sell audio CD's for $97?

  33. #83
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    There's a link between high amount of B12 and some types of cancer.
    B12 is essential for growth and cell division.
    Cancer =uncontrolled growth/cell division.
    There's also a link between high intake of animal products and cancer (animal products generally contain more B12 than plants, which normally contain low or no B12).

    Based on this info, and the assumption that too high levels of B12 both causes exaggerated growth (represented as body height) and exaggerated cell division / cell growth / cancer, I have assumed that there would be a link between body height and cancer.

    After googling cancer and height, I found this:

    http://www.bmj.com/cgi/content/full/317/7169/0/d
    An association is known to exist between adult height and cancer mortality, but the reasons for this have been unclear. On p 1351 Davey Smith et al report on prospective observational data from the Whitehall study which confirms this association. They propose that dietary energy intake during growth may explain the increase in mortality with height. Pre-pubertal growth is largely due to increasing leg length, and Gunnell et al (p 1350) report a study of such data from the Boyd Orr cohort. They found that childhood leg length showed a significant positive association with mortality from non-smoking related cancers and suggest that both could be explained by changes in insulin-like growth factor concentration related to diet.
    http://www.aicr.org/site/News2?abbr=...ticle&id=12899
    “We found that tallness is also probably linked to increased risk for ovarian, pancreatic and pre-menopausal cancer as well,” said Willett. He was careful to note that, although the association between height and cancer is convincing, a tall person is not destined to get cancer.

    Tallness is an indicator of risk, not a cause of it, Willett said. “If you’re tall, the Expert Report’s 10 Recommendations for Lowering Cancer Risk are even more important to you, not less.”
    http://news.bbc.co.uk/1/hi/health/941890.stm
    Height linked to breast cancer risk
    A woman's height, as well as her weight, may be a factor in determining her risk of developing breast cancer.
    Researchers in the Netherlands have been reviewing the data collected in seven major international research studies and have confirmed that taller women have a slightly increased risk of being diagnosed with breast cancer.

    Scientists at Maastricht University looked at research involving 337,800 women, as well as 4,385 cases of invasive breast cancer.

    They found that the risk of experiencing breast cancer increased by 7% with each 5cm increase in height for post-menopausal women, with a marginally increased risk among pre-menopausal women.

    Reviewing results from previous cohort studies has also reinforced the link between weight and breast cancer risk, they reported in the American Journal of Epidemiology.

    Women who are significantly overweight later in life are 26% more likely to develop breast cancer compared with those of average weight.

    Paradoxically, however, being obese appears to have a protective effect in women before the menopause.

    'Tall women should not be anxious'

    Dr Tim Key, senior scientist at the Imperial Cancer Research Fund said the link between height and breast cancer risk had first been identified by comparing international statistics.

  34. #84

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    Default Re: B12 overdose / megadose?

    I've taken B12 in the past because it helped my depression, then I stopped taking it about few months ago when I felt I was doing much better on my depression.

    When I became a vegan I thought it might be a good idea to take it again.
    So, I bought both Vegan One Multiple (100 mcg/ B12) and and Vegan B 12 ( 1000 mcg) from VegLife.

    I've noticed that even when I took 1/2 of the B-12, in addition to the Veg-1 mutltiple, I got that feeling of tingling on my left arm and left leg. Then yesterday, I saw a bit of "acne like" on my face, just 2 or 3 spots.

    Last night, I said to myself all of this must be just in my head and I took for the first time both the multiple and the whole B12 one, so I took about 1100 mcg. The tingling feelings on my left arm and my left leg was stronger and my heart start racing a bit.

    Also, I forgot to mention that I've been eating lots of vitamin B-12 fortified vegan food. I was buying the ones with the highest B-12.

    I don't remember going through side effects like these when I was taking B 12 for my depression but I know it was at much smaller dosage since I always looked for the smallest dosage possible when I bought my suplemnts.

    Any how, I learned my lesson and from now on, I will take only 1/2 of the mutli one every other day and maybe 1/4 of the B 12 no more than once a week.

    This thread has been very helpful for me.........peace, Mike

  35. #85
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    According to this article from 1992 about the effect of the effect of Folinic Acid, B6, and B12 on certain defects (the results are based on testing on mice. Sorry, mice.) "the dose levels should be carefully chosen since high doses of the combined vitamins can actually increase the incidence of certain defects".

  36. #86
    cobweb
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    Default Re: B12 overdose / megadose?

    it's all rather confusing.............

  37. #87
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    OK, here's the short version:
    Too much or too little B12 seems to be a bad idea. For some years, some people have claimed that while too little B12 always is a problem, too much B12 isn't associated with any known problems. Many of the referred links in this thread suggests that the truth is a bit different...

  38. #88
    cobweb
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    Default Re: B12 overdose / megadose?

    i know, and thanks, but i'm still a bit confused - i take a mega b vit supplement so i'm not sure if i should be taking such a range of b vitamins or just b12, and how much.......

  39. #89
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    Default Re: B12 overdose / megadose?

    I've been taking a megadose for ages, got back from the doc who told me my B12 levels are 'excellent'. Now i don't know whether to keep taking it or switch to a lower dose Maybe it would help if I read the thread
    Silent but deadly :p

  40. #90
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    How high was your megadose(s)?

    A report from 1997 described children getting muscle twitching and/or seizure-like symptoms upon treatment with B12 in doses of 500 mcg or more. Other infants have developed tremors at doses of 300 mcg. Since you're not kids, cobweb and Hemlock, you should be able to handle more than that, but unless you have very special needs, I can't see why one would want to take B12 megadoses on a regular basis...

  41. #91
    Mike_
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    Default B12 supplements causing dizziness, nausea

    Multivitamins didn't seem to cause it, but for a week I took a daily B12-only supplement bought in a pharmacy (250mcg of cyanocobalamin), and now I feel dizzy and nauseous. It's very annoying.

    I've stopped the supplement a week ago but it persists.

    Anyone had this? Help is appreciated.

    Thanks.

  42. #92
    Mahk
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    Default Re: B12 supplements causing dizziness, nausea

    See a doctor. Your symptoms could be caused by any number of different reasons, many of which have nothing to do with being a vegan or what type of vitamins you take.

  43. #93
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    This thread is about overdoisng on B12, but here's some related info about possible side effects of taking cyanocobalamin:

    http://www.answers.com/topic/vitamin-b12


    Precautions

    People who are sensitive to cobalamin or cobalt should not take cobalamin supplements. Symptoms of hypersensitivity may include swelling, itching, and shock. Adverse effects resulting from B12 supplementation are rare. Cobalamin should also be avoided by those who have a type of hereditary optic nerve atrophy known as Leber's disease.

    Side Effects

    Very high doses of cobalamin may sometimes cause acne.
    Allergies

    Vitamin B12 supplements should be avoided in people sensitive or allergic to cobalamin, cobalt, or any other product ingredients.


    Side effects, contraindications, and warnings

    Dermatologic: Itching, rash, transitory exanthema, and urticaria have been reported. Vitamin B12 (20 micrograms/day) and pyridoxine (80mg/day) has been associated with cases of rosacea fulminans, characterized by intense erythema with nodules, papules, and pustules. Symptoms may persist for up to 4 months after the supplement is stopped, and may require treatment with systemic corticosteroids and topical therapy.
    Gastrointestinal: Diarrhea has been reported.
    Hematologic: Peripheral vascular thrombosis has been reported. Treatment of vitamin B12 deficiency can unmask polycythemia vera, which is characterized by an increase in blood volume and the number of red blood cells. The correction of megaloblastic anemia with vitamin B12 can result in fatal hypokalemia and gout in susceptible individuals, and it can obscure folate deficiency in megaloblastic anemia. Caution is warranted.
    Leber's disease: Vitamin B12 in the form of cyanocobalamin is contraindicated in early Leber's disease, which is hereditary optic nerve atrophy. Vitamin B12 can cause severe and swift optic atrophy.
    There is no scientific evidence to support claims that cyanocobalamin can treat various other problems (such as allergies, mental problems, nerve disorders, skin problems). Treating yourself with large doses of cyanocobalamin can be unsafe. Do not treat yourself without your prescriber's advice.
    What side effects may I notice from taking cyanocobalamin?

    Serious side effects from cyanocobalamin are rare, but severe allergic reactions (progressing to fluid in the lungs or congestive heart failure) can occur. Side effects with cyanocobalamin include:
    • chest tightness or pain
    • difficulty breathing, wheezing or shortness of breath
    • skin rash, redness and itching

    Minor side effect with cyanocobalamin:
    • diarrhea
    Let your prescriber or health care professional know about this side effect if it does not go away.

    As mentioned many times earlier, avoiding getting too little (and not too much) B12 is what normally needs focus...

  44. #94
    LuVegan15
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    Default Re: B12 overdose / megadose?

    I get my b12 from Marmite. 60% of RDA per 4g serving. God knows I eat too much of it, haha.

  45. #95

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    Default Re: B12 overdose / megadose?

    I'm worried that my multivitamin may be providing too much B12. I searched until I found a vegan multi w/ the lowest dose of B12, but it is 100mcg which is 1666% of the RDA. The other thread about B12 excess being linked to prostate cancer raised my worries as my husband also takes this.

    Maybe we should ditch the multi and just try to get B12 from fortified food?
    Or maybe only take the multi occasionally? If so, how often should we take it.

    Korn, your extent of research into the B12 issue and understanding of the issue is impressive. I would really appreciate your advice. Thanks.


  46. #96
    helen105281
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    Default Re: B12 overdose / megadose?

    I take 1 fizzy B vit tablet a week. It does 666% RDA.

  47. #97

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    Default Re: B12 overdose / megadose?

    I was thinking of maybe only taking the multi once a week b/c of the b12, but then that would mean I wasn't getting the other vitamins in it on a daily basis. Idk, very confused.


  48. #98
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Hi Veganwitch,

    I can't really give any general advice (I don't even know if you need B12), but some people take a multi daily (if they need a multi) - preferably with very little B12 in it, and take B12 (eg. 9-10 mcg) as a separate supplement. You may not need either of these, or you may have very high or very low B12 levels, depending on what kind of food and supplements you have been taking the last few years. The problem is that your B12 needs vary based on a lot variables: coffee intake, stress, sugar consumption and a lot more, which is why I can't really give you any advice.

    A little too much B12 is probably not a problem, but then again - all the articles that link high intake of animal products with various diseases could have to with a higher B12 intake, because a higher B12 intake is one of the things that is common for people who eat meat etc. (There's also animal proteins, fat and more). As we know, too little B12 definitely in't good either.

    In general, if someone have had a high 12 intake for a while (from food or supplements) it could be a good idea to stay away from B12 for some time - unless, of course, they have a deficiency /absorption problem.

    What is it that you think you need form those multis? Most multis contain B12, and the B12 found in multis are in various degrees inactive B12 analogues, which we don't seem to need (and which may even be harmful, although not so harmful as some people assume they are).

    My best advice would be eat as healthy as possible, avoid as many nutrient killers as possible, and check your B12/MMA/homocysteine levels to check if you actually need therapeutic amounts of B12. Make sure having some fun while you're doing all of this.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

  49. #99

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    Default Re: B12 overdose / megadose?

    Quote Korn View Post

    The problem is that your B12 needs vary based on a lot variables: coffee intake, stress, sugar consumption and a lot more
    Hi Korn, thanks for your response. I'm going to do some research on what you mentioned above. I didn't realize that those things can affect B12 levels.

    What is it that you think you need form those multis?
    I'd been vegan for about 7 years w/ no supplementation. For the past couple of years I've been taking the multi that includes B12. I felt my eyesight deteriorating (meaning I probably could use glasses but wanted to avoid it) and I also live in mortal fear of breast cancer. So I was looking for vitamins that were good for eye health and breast health. Plus I had been experiencing extreme weakness in my upper arms. It was nearly impossible to raise them. I felt I was probably deficient in B12 and other vitamins. After I started the multi the arm weakness went away. Maybe it was a coincidence, idk.

    My best advice would be eat as healthy as possible, avoid as many nutrient killers as possible, and check your B12/MMA/homocysteine levels to check if you actually need therapeutic amounts of B12. Make sure having some fun while you're doing all of this.
    Who wouldn't have fun doing all that? I do try to eat healthy but I know I could do a lot better. When and if there is ever a blue moon and I find myself in a doctor's office letting them take blood, I'll have those levels checked.

    Again, thanks. I really appreciate your input


  50. #100
    Ex-admin Korn's Avatar
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    Default Re: B12 overdose / megadose?

    Hi again,

    if you have been vegan for 7 years with no supplements, it's very unlikely that you have too high B12 levels, but it's a real chance that you'll have too low B12 levels (without supplementing) due the reasons discussed in this and several other threads.

    At some point in life (way earlier than most of us believe) people will experience will reduced eye sight, hearing abilities will be reduced over the years... - and so on. People who live on some special diet may as assume that whatever problems they have come from that diet (which they of course sometimes do), and forget than billions of people not living on any special diet also have health problems. But there's no reason no not do our best to avoid health problem - especially since an ill vegan easily could accused for being ill because he was a vegan, while an ill meat eater is 'just sick'. Remember that even among meat eaters, of which 50% also take some sort of supplements - low B12 levels are quite common, and the tests that document this don't even take MMA levels and homocysteine into consideration.


    Who wouldn't have fun doing all that? I do try to eat healthy but I know I could do a lot better.
    Good luck in doing a lot better then!
    Last edited by Korn; Oct 16th, 2009 at 07:40 PM.
    I will not eat anything that walks, swims, flies, runs, skips, hops or crawls.

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