Doctor's Note

This is the final video of a three-part series with the latest information on the safety of dietary supplements. For the first two, see Dietary Supplement Snake Oil, and Heavy Metals in Protein Powder Supplements. For background on the folic acid versus folate story (which may explain any multivitamin/breast cancer connection), see Can Folic Acid Be Harmful? For more on avoiding esophageal cancer, see Poultry and Penis CancerCoffee and Cancer; and Bacon and Botulism. For how to boost your absorption of carotenoid phytonutrients (like beta carotene), see Raw Food Nutrient Absorption, and Forego Fat-Free Dressings? Pretty scary about green tea supplements, but green tea has a variety of health-promoting properties. Check out my other videos on tea.

For further context, check out my associated blog posts: Plant-Based Workplace InterventionAvoid Cooked Meat Carcinogens; and Probiotics and Diarrhea.

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  • Michael Greger M.D.

    This is the final video of a three-part series on the latest information about the safety of dietary supplements. See Dietary Supplement Snake Oil and Heavy Metals in Protein Powder Supplements for the first two. For background on the folic acid versus folate story (which may explain any multivitamin breast cancer connection), see Can Folic Acid Be Harmful? For more on avoiding esophageal cancer see Poultry and Penis Cancer, Coffee and Cancer, and Bacon and Botulism. For how to boost your absorption of carotenoid phytonutrients like beta carotene see Raw Food Nutrient Absorption and Forgo Fat-Free Dressings? Pretty scary about green tea supplements, but green tea has a variety of health-promoting properties. Check out my 21 videos on tea, and hundreds of videos on more than a thousand other topics.

    • HemoDynamic, M.D.

      Good week of Vid’s!  In the future it would be interesting to see something on some of the supplements that are “good” for us like NAC (N-Acetyl-cysteine) and Milk thistle for liver protection.  Acetylated L-Carnitine for brain protection.  That is, if in fact, they are good for us. 
      When on the liver transplant team we routinely used NAC and Milk Thistle and some studies show some benefit to Acetyl-L Carnitine for brain protection. 
      Just curious if in the future you are bored and have nothing else better to do to get you take on these supplements ;-}
      Have a great weekend!

      • Michele

        Interesting . . . I also am interested in Dr. Greger’s thoughts on these supplements.  Should be a GREAT weekend, I’ll be attending the Health, Healing, and Happiness conference in Las Vegas!  Thank you for all the brilliant info Dr. Greger!

        • HemoDynamic, M.D.

          Good to see you again!  I hope all is well.  Have fun in Vegas but I hope what you learn in Vegas doesn’t stay in Vegas. I hope you bring all the good stuff you learn back to share with everyone you treat!

      • HemoDynamic, M.D.

        In replying to myself it seems that NAC (N-Acetyl Cysteine, no it’s not an acronym for Not Another Chemical or Not Another Comment) may be one of the few useful supplements:

        Antioxidants (NAC) as antidepressants: fact or fiction? Fact !

        H. pylori treatment with NAC: making Resistance unresistant. Fact

        NAC attenuated inflammatory response and acute lung and kidney injury after hemorrhagic shock:  Fact!

        NAC can prevent Retinal Ganglion Cell Death and may help prevent Glaucoma: Fact!

        • Stefan Juhl M.D.

          Thats interstering especially the part with oxdative stress and depression – dr Greger now it is you! Any comments?

    • Lieberman

      Hi Doc,

      I’m curious if L-Theanine is one of the green tea products you’re referring to here?  As it been widely praised as an alternative to benzo’s. :(

  • Stefan Juhl M.D.

    Correct me if I am wrong. Folate (in food) and folic acid (in pills) is not exatly the same molecule. Thats one reason why pills does not work. Beta-carotene is just one out of several carotenoides and you need them all. Thats another reason why popping a pill (with only beta-carotene) does not work. Several intelligent people (including dr Greger I think) says that food is a package. You have to eat the package, not just one single vitamine, nutrient og minerale. So bottom line: You can not cure disease caused by meat, dairy, eggs, fre oils and 6000 kcal/day with prescription drugs or with selene, A-vitamine, beta-carotene or any other “wonder” vitamine. Reservatrol probably has some effect if you get it from berries ond red wine (yeah ! :-) ) not from a pill. Eat food, not pills.

    •  I’m pretty sure that the experiments on animals which showed health benefits for resveratrol were all done with concentrates, equivalent to the pill form since it is found in such low quantities in foods. Red wine, which contains the highest concentration of resveratrol in a food, has no more than 12.5 mg per liter- if you’re lucky. Yet usually they recommend 250 mg per day. However, I agree that it’s easy to get adequate levels of folate, selenium, beta carotene and vitamin C from plant-based foods.

      • Stefan Juhl M.D.

        Thanks for your input PaulC. I have heard that resveratrol is not “stable” in a pill, so when you buy the pill there is no active resveratrol left. Do you know anything about this? Drinking 20 liters of red wine pr day is probably too much! Even if it is from California :-)

        • jw16899

          The supplement I take is in gel form. The Resveratrol gets absorbed into the blood stream directly from inside the mouth. One packet is like drinking 85 bottles of red wine.

    • HemoDynamic, M.D.

      Dr. Juhl, I’m eating, I’m eating already–my rice, quinoa, lentil and arugula salad already!!  And it’s D-lish!

      • Stefan Juhl M.D.

        Yes it is. Have you also noticed that a vegan diet makes you more energetic and alert? I have. I hope that your patients are following your advice, because then they will become more healthy and probably get rid of a lot of their prescription drugs for DM, hypertension, chol. and so forth. Vegan ruels !!!! Dr Dynamic – have a nice vegan weekend !

        • HemoDynamic, M.D.

          All my patients that follow a Vegan diet get at the very least a little better 100% of the time!  No exceptions.  They may not cure every problem but they lower their cholesterol, lower their blood pressure, stop their acid reflux, stop their insomnia, reduce their anxiety, reverse their Type 2 Diabetes, inhibit, stop and even reverse their autoimmune disorders and their cardiovascular disease, and they ALL improve their quality of life.  And that’s what it’s all about–Living Better!

          You have a nice Vegan weekend as well my friend!

          • Ghazeltine

            A few months back I purchased this wonderful blender and started having a “dr. greger shake” daily in the morning. I eat a primarily plant based diet and have for many years.

            I just had all my blood work done and my TSH was off. (hypothyroid for many years) When I went on the synthroid website it said an increase in fiber can cause a change in levels. Weird right? Who would have thought I would need to increase my thyroid meds just because I increased my fiber?

    • Justin

      Folic acid isn’t the only form of folate supplement. Other forms include folinic acid and L-methylfolate. I would imagine the adverse effects of supplementation would probably be eliminated if either of these other forms were used. 

      This article talks a little bit more about that:

  • April Barnswell

    I try really hard to get all of my nutrients directly from the whole plant foods. I make a point of rotating our fruits and veggies each week so that we eat a wide and varied mix of plants. We always eat lots of cruciferous plants daily, but we also try to add in other veggies and fruits on a rotating basis. We eat a lot of vegan foods on a daily basis that are supplemented with B12 (i.e., almond milk, coconut milk yogurt). But we also add a sublingual B12 pill, because I’m afraid to fall short on B12. I also take a general multivitamin most days. Other than that, we have stopped taking any other supplements, because I read that the food is always the best source for nutrients. I can understand why nutrients in isolation are not nearly as good as nutrients in their natural, synergistic state.  

    • Stefan Juhl M.D.

      If you live 100% vegan B12 is essential. As a neurologist a have seen B12 myelopati – and you dont want that! Some authors recommend methylcobalamin instead of cyanocobalamin – does anybody have a comment? – dr Greger?

      • john

        I believe that will turn out to be a 100% myth over time… long time vegan.. 10+ years, I don’t supplement it. I know 60 somethings vegan most of their life who have never supplemented either. Seems to be the intestines synthesize B12 and it only becomes a problem when something causes it from being absorbed. Hence why many meat eaters end up with b12 deficiencies despite a “high intake of B12”

  • Strix

    What I never get is whether the problem is with the high amount of the product being consumed in concentration, or whether there is something about the pill/extract/powder ITSELF or the processing that is the danger. If it’s just the overdose, then the supplementation itself isn’t really the problem, just the amount.

  • maya

    Can you speak about moringa oleifera as a supplement?

  • lani

    Aside from my Vit B12 supplementation as a vegan, I simply take a Centrum silver(along with extra calcium and vit D) Is taking a daily multivitamin harmful?

  • BeckyN

    Are CoQ10 supplements good or bad for you?

  • Florence

    Dear MD M. Gregor

    I am unsure of calcium supplements.

    was told to take Calcium Citrate and vitamin D by a MD who specializes
    in this area after I suffered a broken hip and had two hip surgeries,
    one of which was from a staff infection contracted while in recovery.
    After that I was referred to a physician who told me to take supplements
    (First he recommended Fosomax which I refused. Okay, so I
    have been taking Calcium Citrate 400 milligrams and Vitamin D3 500 mg
    in a Puritans Pride product.

    Then, I was reading on line that most Calcium supplements are made from
    rock and are not digestible and they recommended their brand called AlgaeCal
    which is a plant based Calcium. From what I read in their add and the
    testimonies it sounds like a great product. Do you have any feedback on

    Also I would be interested in knowing more about another item that is advertised by Vitacost; they advertise a Chelated Calcium and Magnesium.

    would love to hear your take on these products and if indeed I need to
    be taking them because my bones are thinning and I Do Not want another
    fall and break.

    Hoping to hear, Florence

    • The best resource I have come across is the book, Building Bone Vitality by Amy Lanou. She read through over 1000 studies for the book. The best approach seems to be a plant based diet with weight bearing exercise such as walking. Preventing falls is important as we get more “experienced”. Fitness is aerobic, strength, flexibility, balance and stability. The weight of evidence at this point seems to not put much value in supplements and treatments with drugs should most likely start with thiazide diuretics. It is important to get proper information and then work with your physician(s) to determine which path is best for you. Good luck.

  • Rod Nyctophylliac O

    What brands of supplements were used for those studies? I mean there is a
    lot of non reputable companies out there that sell supplements that are
    not even derived from natural sources. They spend most of their money
    on advertising instead of sourcing from good clean natural sources. This
    is the problem I have with these studies. I always buy my supplements
    from reputable companies that have a good if not excellent track record.
    Unfortunately that is not the case for most people and from what I’ve
    seen it’s the same for most of these studies that hit the main stream media
    alleging that supplements are of no use.

  • fmnt

    Hi Doctor! Great video! Is vitamine b9 supplementation dangerous even with high blood level of homocysteine? Shouldn’t I take even 3 mg of vit B6, 5 mcg of B12 and 400 mcg of vit b9 apart from the diet?

  • Boldi

    According to this video and a few others and some articles, I stopped taking multivitamin pills (which I have been doing for some 10 years..).
    I’ve had acid reflux for many years and I’ve been taking medicine for that for about 7-8 years (proton-pump inhibitors). These medicines always made me very tired, dizzy, dull..I even went to the Gastroenterology 2 times for checking my stomach and esophagus and duodenum with that pipe and video camera. It is terrible experience! :-). The second examination was just 3 weeks ago because I’d been in so much pain for many weeks. And then I saw this video at about the same time… So after the examination I stopped taking the multivitamin pills (folic acid in it..). And guess what? My stomach and esophagus pain is 99% gone!! Reflux is gone!! No joke. I got another strong medicine for my inflamed esophagus at the hospital, 3 weeks ago, but I did not take even 1 pill in the last 3 weeks! I have become vegan almost one year ago, and I was very said and angry, that even with vegan food I was feeling crapy all the time because of this acid and stomach pain. (I had other issues as well, like high blood pressure and chronic fatigue, which all have improved significantly, except this one problem.) So now, it seems, after many years, I’ve solved this issue too. Just by stopping taking multivitamin with folic acid in it. Now I only take B12 and vitamin D, nothing else (and of course, I eat lots of leafy greens with FOLATE in them!). How stupid I was taking these artificial multi craps for so many years not knowing I’m just hurting myself.
    Now I know the answer to my long lasting problem!
    Thank you!
    (Please excuse my poor English, I’m Hungarian.)

    • Thea

      Boldi: Thank you for sharing your story. I find it so encouraging when people are able to fix their own problems. Good for you for giving it a try. I hope this good health continues for years!

      • Boldi

        Thea: Thank you! It’s almost 2 months without taking multivitamin pills, and it’s also 2 months without acid reflux! No more proton-pump inhibitor drugs. I feel very well. :-)

  • Geea

    Is there a risk in taking B12 supplements?
    There are some studies that show increased risk of cancer in patients taking B12 + folic acid supplements.

  • patipnuts

    My husband has had Tropical Sprue several times. The first time he was
    undiagnosed for three years. The treatment is 6 months of Doxycycline
    and 5 mg of “Folic Acid”. We became vegan in 1998, during his second
    treatment. When he does not take the Folic, his small intestine
    deteriorates and he gets sick again. I have tried to switch him to
    Folate, but it is really difficult to find Folate without Folic A
    included. His prostate is “huge” but so far no cancer. I strive to serve
    beans and greens every day, but we travel out into rural Philippines to
    teach and we can’t always do it. Also, our area does not often have
    greens readily available (or other fresh veggies for that matter). I
    read that with “Quatrofolic” he could take less. Have you seen any
    studies that back that up? Does research show that Folic Acid causes BPH
    to worsen? Any suggestions how to lower it?

  • There are B12 supplements without folic acid.

  • Mick

    Ever since I started WFPB diet I have to agree that plant foods are much much better than vitamins and supplements. Almost every supplement (like resveratrol) causes me strange side effects (like headaches in case of resveratrol).
    There is one exception to this rule…
    I need to take diuretics (which are used to treat epilepsy in my case) and these must cause me to lose B vitamins and especially magnesium. I draw that conclusion based on the fact that recently I became very very tired and sleepy. Two days of taking B vitamins and magnesium and I got a lot better. So that’s that but otherwise I concur.

    • jw16899

      How long did you take the Resveratrol? The one I take sometimes gave me some side effects. But it went away after two weeks. My Chinese medicine doctor told me that is not uncommon. In fact, he said that is called 暈眩反應 and is a good thing. It means my body was responding to it.

      • Shaylen

        “side effects” can be a detox effect, but what you were advised sounds like some really bad advice… to ignore possible symptoms. When it comes to resveratrol supplements, all the evidence that I’ve come across, like most antioxidant supplements, is to stay away from them. Antioxidant supplements are NOT a good idea, they need whole foods to work with otherwise they themselves become oxidants (which is probably the reason people “got worse” when taking vitamin C supplements as the same thing occurs with this antioxidant).
        The more antioxidants, the better! BUT, in food, NOT supplement form. Here is a great article explaining it all:

        Also check this out, very informative and you’ll definitely want to watch (those taking resveratrol supplements undermine the positive effects of exercise, or at least some of the effects):

    • Shaylen

      Some whole foods supplements can be good, if you can’t get all your b vitamins from your diet then I can’t imagine whole foods supplements would harm you. It’s necessary to supplement with B12, as it is. Also vitamin d supplements can be beneficial and necessary in certain locations during certain times of the year.

  • Are there any brands that offer safe supplements? Or are they all bad?

  • Kristin

    In Dr. Greger’s book “How Not to Die” on p 158 it states that antioxidant supplements like Vit A, Vit E in pill form were associated with increased death in those who took them. Were these synthetic supplements or whole food supplements? Can you please comment on whether or not whole food supplements (like “Standard Process” brand) are any better for you than synthetic supplements? The chiropractor I’m seeing has recommended Standard Process brand supplements but I’m not sure if there have been any research studies on them or not.

    • Dr. Jen

      Hi Kristin,

      Thanks for the question! The specific studies Dr. G cites in this section of the book don’t specify how the supplements were made. However, most of the data on supplements, “whole food” based or not, seems to indicate that they are not as good as just consuming actual food.

      • Kristin

        Thanks Dr. Jen!

  • Shaylen

    What about folic acid that is added to virtually all nutritional yeast? Dr. Greger promotes nutritional yeast so I can’t imagine it’s anything to worry about.