Doctor's Note

For some context, please check out my associated blog posts Are Multivitamins Good For You? and Eating To Extend Our Lifespan

  • http://www.facebook.com/profile.php?id=676800493 Benjamin Stone

    What about Vitamin A? I quote:

    “Researchers at Newcastle University in England, led by Dr. Georg Lietz, found 47 percent of volunteer group of 62 women carried a genetic variation that prevented their bodies from effectively converting beta-carotene into vitamin A.”

    If this is the case, it implies nearly half of vegan women do not have the enzymes that convert carotenes to vitamin A – should we be concerned? Do some people simply require this vitamin preformed (or by supplement)?

    • Michael Greger M.D.

      I assume you’re talking about this study? That was over ten years ago. According to a review published last year, “Methods to assess the bioavailability and bioconversion of provitamin A carotenoids have advanced significantly in the past 10 y….” Though the conversion is not as efficient as we used to think, there is no need to consume preformed vitamin A according to the Institute of Medicine. But that doesn’t mean we don’t have to beta-carotene containing foods! That’s one of the reasons I recommend we eat dark green leafy vegetables every day.

  • jen.ferdinand

    Hi Dr. Greger. Thank you so much for creating this site. It is very much appreciated.

    I noticed the bottle of Vitamin D in this video was Vitamin D2. I have read that D3 is the better source for us(colecalciferol). Can you please clarify?

    Many thanks,

    • Michael Greger M.D.

      Such a good question. Taken daily in doses under 2000IU, vitamin D2 (ergocalciferol) and D3 (cholecalciferol) appear bioequivalent (meaning they both work just as well in your body). However if your physician suggests you take large intermittent doses (such as 50,000IU weekly, then D3 is probably superior).

      • Khari

        Vitamin D2 is Vegan….Vitamin D3 is not Vegan….am I correct?

        • Lindsey

          Correct, but there is a new vegan D3 on the market derived from mushrooms!

          • http://www.facebook.com/profile.php?id=1850995636 Martina Yank Miškić

            Actually,it’s from lichen not mushrooms.

          • Israel Navas Duran

            Actually, a lichen is part fungus and the other part either algae or cyanobacteria.

  • jen.ferdinand

    Thank you so much for clarifying this, as I often see D2 in supplement powders and have not understood why it is used.

  • DanM15

    What would you recommend as a minimum dose of B6, B12 and Vitamin D for someone following a plant based diet?

    • Toxins

      Hello Dan!
      I have studied nutrition extensively and can answer your question.
      Firstly, a variety of plant foods have significant sources of b6 and therefore is unnecessary to supplement.
      Regarding b12, you can find rather high doses in supplements, some containing %5,000 to %16,000 of your daily value. Its of no concern though to worry about getting too much. If you take one of these supplements once a week it will suffice since what you cant use is simply peed out. Also note that vitamin b12 is used every day in extremely low amounts so once a week will replenish your supply.
      Regarding vitamin d, you should take 2,000 – 4,000 IUs of Vitamin D2 or D3. I take a deva 2,400 IU vitamin d2 supplement. In experiments, these two types of vitamin d proved to be nearly equivalent so do not concern yourself with what type of vitamin d as long as you get it. Just note that vitamin d2 is vegan but there is a new vitamin d3 derived from mushrooms that is also vegan.

  • Khari

    What vegan options are there for vegans to get Vitamin D from besides supplements and the sun?

    • Alexandra Georgiadis

      There are some vegan-friendly foods that are fortified with Vitamin D such as breakfast cereals and soy milk. Make sure to check the nutrition facts on the food label. But remember if you live in an area where you may not be getting enough sunlight, or if you don’t get enough sun exposure, fortified foods may not be an adequate source of vitamin D. As the video mentions supplementing with vitamin D might be a good idea. You might also be interested in this video, http://nutritionfacts.org/videos/vitamin-d-pills-vs-tanning-beds/, comparing two Vitamin D sources. More information is also available on NutritionFacts.org regarding vitamin supplemention which you may want to check out (since not all vitamin supplements are beneficial) such as this short one http://nutritionfacts.org/videos/are-vitamin-c-pills-good-for-you/ ,which mentions vitamin D along with E, A and C. Hope this helps. Good luck!

  • http://www.facebook.com/profile.php?id=1047747197 Lisa O’Neill

    If vitamin B12 is stored in the liver, then why do we get it from eating meat (rather than eating actual liver)?

    • Anya

      After being absorbed in the small intestine & circulated by the blood, Vitamin B12 is stored throughout the tissue of animals – including the liver. Luckily as we have seen by this video, we don’t need to depend on animal products for our Vitamin B12!

    • Israel Navas Duran

      Liver has higher concentration of vitamin B12 than other organs. This is also the case about vitamin D, A and E, up to that point that eating liver of certain animals can be toxic or even lethal (e.g., seal, polar bear).

  • vegantruth

    How much Vitamin D is too much? Whats the recommended supplementation? Is there any science to Vitamin D as a cure for the common cold?

    • SArmstrong

      You can get too much vitamin D; since it is a fat soluble vitamin it can accumulate in the body to toxic levels. If you take significantly more than the RDA (which most agree is too low at 400 IUs daily) it may be wise to get your blood levels checked after supplementing for a few months. At doses more than 10,000 IUs daily there may be an increased risk of kidney stones. In the Nutrition Facts video 4,000 IUs daily in winter is mentioned; I think the chance of toxicity is unlikely at this dose. There are anecdotal reports of vitamin D supplementation preventing or reducing colds in winter. I know of two randomized studies that did NOT show vitamin D reducing upper respiratory infections ( Epidemiol Infect. 2009;137(10):1396 and J Infec Dis. 2010;202(5)809 ).

      • http://www.facebook.com/ve3tru Peter Trumpickas

        I would look into that some more, what exactly constitutes a toxic dose of vitamin D has yet to be
        determined. Though it is possible this amount may vary with the
        individual. In fact latest studies show the toxic levels to be actually much higher.Published cases of toxicity involve intake of ≥ 40000 IU (1000 mcg) per day. In two cases an intake of over 2,000,000 IU per day. This over-dramatization of the toxic effects of vitamin D can only do harm scaring people away.

  • Lisa21012

    It was recommended to get cyanocobalamin but those are supplemented with folic acid which we shouldn’t be taking. I like taking it daily so I’m looking for 250 mcg. Is there a brand of B-12 that anyone likes?

  • PeterGerry

    How much of the body needs to be exposed to get “15-30 min mid-day sun”?

    • Toxins

      Hello PeterGerry!

      This is an excellent question! Please see my response to GregV at the bottom of this page http://nutritionfacts.org/videos/vegan-epidemic/ describing many aspects of vitamin d including how much you need to get on your body for it to be effective.

      Let me know if you have further questions!

  • evanbrand

    What foods/protocol can reverse gray hair (or revert gray hair to original color); what foods/protocol can revert hair thinning/balding? ( I saw 4:13 in this video, and was curious if there are other suggestions).

  • Stacia

    Hi Dr. Greger,

    I just watched your newest video and it was fantastic as usual. The segment about the adult requirement of 2000 units/day for Vitamin D was interesting and helpful. Can you please tell me what a child’s requirement is likely to be? We have a three year old.

    Thank you,

    Stacia Mesleh

    • Michael Greger M.D.

      I’m so glad you’re finding the videos useful. The official (Institute of Medicine) recommendation for those over 1 year of age is 600 IU a day of vitamin D. In two weeks I’m going to be rolling out a series of vitamin D videos from my volume 6 DVD–stay tuned! (if you can’t wait, I have a special holiday sale on my Latest in Nutrition DVDs–all proceeds to charity, of course).

  • tduke

    would eating mushrooms daily be just as good as supplementation or better since they are so high in vit D?

  • Michael Greger M.D.

    For some context, please check out my associated blog post Multivitamins and Mortality!

  • Phil

    Does suntanning und a suntan bench promote the body’s production of D2? (1-2 times suntanning, approx. 5-10 mins per go)

  • http://www.facebook.com/gurnani.sunny Sunny Gurnani

    Hello Dr, Thanks for the Video. I live in SF Bay Area and I am a native from India so should I take 4000 IU of Vitamin D2 or more?

    Also for B12 There are some articles about Methylcobalamin being better but than cyanocobalamin
    http://www.naturalnews.com/032766_cyanocobalamin_vitamin_B-12.html

    Can you please recommend? Also if you think cyanocobalamin is bad can you please update your site to have B12 recommendations for Methylcobalamin just for the benefit of community.

  • http://www.facebook.com/betsy.gaines.50 Betsy Gaines

    Fortified foods like cereal and almond milk use unmethylated forms of b-12 which contributes to b-12 deficiency in folks like me with an mthfr defect. It is supposed that 40% of the population has this defect, so fortifying cannot be the answer for us.

  • Stephen Lucker Kelly

    Upside down mushrooms soak up Vitamin D too! :-) So if you do this then you will also get lots of vitamin D too! :-)

    • Arjan den Hollander.

      You really think turning bacteria upside down makes them produce vitamin D?

      I think a few biology classes on your part are in order here.

      • Thea

        Arjan: Mushrooms are a fungus. And yes, turning them upside down helps them to make the vitamin D. Check out the following link and notice the paragraph that I highlight below.

        http://www.fungi.com/blog/items/place-mushrooms-in-sunlight-to-get-your-vitamin-d.html
        “Here is a simple experiment we did one summer afternoon in Kamilche Point, Washington. We compared several forms of organically grown shiitake mushrooms, which had starting level of 100 IU/100 grams. We compared the vitamin D levels of three sets of mushrooms, all from the same crop. The first was grown and dried indoors. The second set was dried outdoors in the sunlight with their gills facing down. The third set of mushrooms was dried outdoors in the sunlight with their gills facing upwards for full sun exposure. The most vitamin D was found in shiitake dried with gills up that were exposed to sunlight for two days, six hours per day. The vitamin D levels in these mushrooms soared from 100 IU/100 grams to nearly 46,000 IU/100 grams (see chart). Their stems, though, produced very little vitamin D, only about 900 IU. Notably, vitamin D levels dropped on the third day, probably due to over-exposure to UV.”

        Hope that helps.

        • Arjan den Hollander.

          Very thorough answer, thank you for taking the effort of writing it. Informative.

          This explanation actually makes a lot of sense thrue the action of exposing a vastly larger surface area to uv radiation.

          This is off course something else completely to just simply turning mushrooms on their hoods and expect vitamin D to appear as if by magic. What I took from reading the OP.

          But tnx Thea, good stuff!!

  • Mark Hazell

    What about DHA? Since DHA only comes from fish (and some sea vegetables) shouldn’t we vegans be concerned with getting enough? Another thing is that I think I’m not getting enough calcium, what sources do you recommend for those? I’ve been taking a supplement for that as well and would like to cut down on those supplements.

    • Israel Navas Duran

      Sea vegetables? I think you have the wrong idea of what dinoflagellates actually are.

  • lovestobevegan

    Hi Dr. Greger,
    The link to your blog “Multivitamins and Mortality” seems to be broken.
    Take care,
    Michelle

    • Ariel Levitsky

      Hey Michelle,

      The defective link has been replaced with Are Multivitamins Good For You?

      Thanks for letting us know!

  • Brian Bohmueller

    Sounds like a well researched video. Glad to see the (verily unregulated) multivitamin craze (funded by big pharma) isn’t being embraced by sensible Vism. As a new vegetarian mindfully moving toward veganism, i still eat vegetarian dairy products and local, “free range” eggs, so I don’t think I need to be concerned about B12 supplements yet. I’m due for a physical soon…are there tests I can request to confirm I have ample, complete nutrition?

    • Tommasina

      Hi Brian, Dr. Greger has a great video on testing for B12– http://nutritionfacts.org/video/new-vitamin-b12-test/ . Hope that helps! Best of luck with your transition :)

    • Susan

      I supplement for vitamin B-12 because I do not want to increase my blood cholesterol by regularly adding animal proteins to my diet. That is part of the reason I eat vegan. The other reason is that eating animal protein increases pain and inflammation in my body, which is even more noticeable since fracturing my lumbar spine.

  • Arun Mukherjee

    Dr. Greger, the video does not tell me what would be a safe daily dosage of Vitamin B12. I recently heard a radio show which suggested to me that I might be taking too much (1000mcg). Would appreciate clarity on this important matter.

  • tony

    I would rather eat savoury nutritional yeast (tastes good) as a whole food rather than a supplement and the brand I have is lotus and one teaspoon is 500% of your daily b12 plus heaps of other b group nutrients as well.

    • Susan

      I give my kitten nutritional yeast to coat her certified organic kibble every day as a way to reduce fleas. She loves it and has zero fleas.

      The container I use is 10 years old and has spent most of its life in the freezer. Does anyone know if Kal brand is genetically engineered to resist Roundup?

    • mbglife

      But you don’t mean to suggest that nutritional yeast naturally contains B12, right? It only contains what is added to it, since nutritional yeast otherwise contains none.

  • Manm

    Hello Dr. Michael Greger! Are the B12 supplementation and B12 fortified foods really the only safe vegan ways to get that vitamin? Isn’t yeast a good source of B12? Much people who thinks they are omnivore says the only way to get it is by eating animals… some admits we can take it by fortified foods (sometimes forgetting about supplementation too but, anyway…) and a few people talks about yeast, spirulina…
    Well, my doubt is: if yeast is a good (and natural) source of B12, since they and bacteria are the only ones who truly produce it, it is our natural way to get B12, isn’t? It makes me confused because supplementation and fortified foods actually are not natural sources, if we look closer, up because:
    1) Men has to produce it (it isn’t naturally present in nature);
    2) Their production is not sustainable because of the plastic/glass bottles and all the artificial things used to its production and transport, so it has an impact in nature (significant or not) ;
    3) The reason of the cheap production of cyanocobalamin is its (little) content of cyanide.
    I am on the 10th grade, and, my school’s biology manual says yeast are present in places rich in sugars and on the peels of juicy fruits such as red grapes, what lets me pre-conclude that eating those fruits is the natural way to us to get B12.
    Can clarify my doubt?

  • steven bucelato

    thank you for all your info!! my question is, if i cant find b12 in pill form but i have found it injectable,- bottles of 1000mg,is that ok?¿ thank you

  • Grace

    Are there any other supplements that you recommend for vegans or any lab tests that should be done to check for deficiencies ? In the past (in your video about a 40 year old vegan dying from a heart attack), you also recommended DHA for pregnant breastfeeding women and recommendations for vegans including calcium, iodine, iron, selenium, zinc, and omega 3s (from flax seeds). The flax seed supplementation seems rather easy, but the other minerals may be more difficult to regulate. What do you think of the over the counter vegan vitamin supplements such as “Deva”?

  • Sarah V Lucas

    Supplementing all bread (in Australia, don’t know about the US) with folate dramatically reduced incidence of birth defects in children. I think mandatory grain supplementation with B12 would be a good idea considering that it is getting harder and harder for anyone on any diet to meet their requirements.