Doctor's Note

More on calcium in cow’s milk versus calcium in plant-based foods:

Alkaline Diets, Animal Protein, & Calcium Loss
Calcium Absorption: Soy Milk Versus Cow Milk
New Mineral Absorption Enhancers Found

And more on the health risks of dairy consumption:

Dairy Estrogen and Male Fertility
Trans Fat In Meat And Dairy
Preventing Alzheimer’s Disease with Diet
Carnitine, Choline, Cancer and Cholesterol: The TMAO Connection

And check out my other videos on dairy.  

For more context, see my blog posts: Stool Size and Breast Cancer Risk and How to Enhance Mineral Absorption.

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  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on dairy.  Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

    • qysoul

      Dear Michael,
      What is the truth on dairy causing osteoporosis due to its high acidity level, which creates a new loss of calcium, leeching calcium from the bones to balance the acidity in the body. So when you say Americans get most of their calcium from dairy, does this mean that the calcium is counter beneficial?

    • Melissa La Rosa

      Dr. Gregor, is it safe to use a plant sourced calcium supplement to help us along? How much Calcium is too much? Thanks!

  • Toxins

    What is it you were saying about yogurt not providing the proper pro biotics? Something about them excreting the body?

  • Merrittk11

    This is a great video.

  • Edythe Evans

    Is there any difference between the type of calcium in dairy and the calcium in plants?  Since plant protein and animal protein are not the same, I’m wondering about the plant vs. animal calcium.  Any difference, or is calcium, just calcium?

  • Andrei


    i am a 3rd year student in nutrition, and all I heard about minerals (ex. Calcium) in plants is that they have less bioavailability, and so they absorb in the human body in less quantity than minerals from animal sources (Calcium from milk).

    Could you point me to some relevant studies? because I belive you more than I belive my proffesors.

    • drconniend

      I believe that your professors are speaking about oxalates, a naturally occurring compound, found in many vegetables such as spinach, rhubarb, beet greens, and collard greens. Oxalates have been found to reduce the absorption of dietary calcium from vegetables.

      In one study on rats it was found that 92% and 78% of the calcium from milk was absorbed in comparison to 75.5% and 60% from oxalate-rich green vegetables. However, even though absorption was indeed reduced in the oxalate-rich green vegetables it was still absorbed at 75.5% and 60% (1).

      Oxalates tend to be higher in the leaves of the plant, than in the roots, stems or stalks. Nevertheless, green leafy vegetables such as kale, broccoli and bok choy are excellent sources of absorbable calcium
      because they are low in oxalates (oxalic acid) (2) and they don’t come along with the harmful “baggage” that milk carries.

      1) Pankaja N., etal. Availability of calcium from kilkeerai (Amaranthus
      tricolor) and drumstick (Moringa oleifer) greens in weanling rats. Food/Hahrung. Vol 38, Issue 2, 199-203.1994.

      2) Heaney, RP, et al. Absorbability of Calcium from
      Brassica Vegetables: Broccoli, Bok Choy, and Kale. Journal
      of Food Science. Vol 58, Issue 6, 1378-80. Nov 1993.

      • Toxins

        Excellent study on the calciferous green vegetables. I have been searching for a study of this kind for a while now. Thanks!

      • Andrei

        “Life saviour”! Thank you very much… It’s pretty hard, for me, to see the whole picture on human nutrition when debating themes like this, but i’m still learning.

        • Jules Elise

          So, this study shows that dairy has more Calcium? I’m Vegan, and looking for peep-reviewed articles that show veggies are a better source of Calcium. I’m confused now.

          • ChuckWalter

            I have no science to back this statement up, but from watching many of Dr Gregor’s videos I assume that mammel milk is one of the most calcium-dense food sources found in nature. However, this does not mean that it is the easiest to absorb or that it has the greatest health benefits. As mentioned in the video, cows milk is the PERFECT food . . . if you are a calf. I would advise you instead to look for the most calcium-rich plant food, and not look specifically for publications that PROVE cows milk is an inferior source of calcium. This will ensure that you are researching science without biases. Best of luck! Let me know if you can prove cows milk isn’t the best source, because I have a few avid milk consumers in my house I would like to disprove.

  • mbglife

    Vitamin K2 (not to be confused with K1 from leafy greens) was shown in, The Rotterdam Study, to reduce all cause mortality and specifically arterial sclerosis, by moving calcium from the blood and soft tissues/organs and bonding it back into the bone. But the sources of K2 I’ve seen listed are almost all from animal products, like poultry livers, hard cheeses, dark poultry meat, etc. There are a few fermented foods, like sauerkraut, that are credited with minimal amounts of it. Also, the human gut is thought to make very small amounts but I’ve read that it might be too far down the intestines to be absorbed by the body. And I read that researchers were surprised that heart disease was reduced for those individuals eating the most animal sources of k2, like cheese. There was a directly inverse correlation between the amount eaten and the amount in arterial sclerosis. So the more K2, the less arterial sclerosis, cancer and other diseases.

    Here’s my questions:

    1) Are there any known vegan sources with significant amounts of K2?

    2) If you’re read the study and some of the subsequent ones, do you have any thoughts about the benefits of K2?

    • K1 is produced in plants. Our bodies change K1 to K2 both in some of our cells and via bacteria in our colon. So if you eat more plants with alot of vitamin K1 you will have more K2 in your body. Eating animal sources of K2 isn’t necessary and exposes us to saturated fat, cholesterol, hormones and persistent organic pollutants not to mention arsenic and mercury in fish while putting us at higher risk for a food borne illness aka the “stomach flu” see No known sources of K2. Benefits of K2 comes from eating plants containing K1.

      • mbglife

        Thanks for your reply. To clarify, I’m vegan, but I’m trying to better understand K2 because of the seemingly strong beneficial affects touted for cancers, calcium regulation and bone health. I’ve read as much as I can find on the net, but like most things on the net, there’s a lot of misinformation and confusion.

        Almost everything I’ve read says that the human gut makes very small amounts of K2 and that it’s too far down the intestines to be absorbed by the body. Similarly, most of what I’ve read suggests that the amount converted from K1 is so small as to be inconsequential, hence the reason for the direct correlation between the amount of K2 consumed and longevity. Just as an aside, I note that from the lists I have seen, there doesn’t appear to be any K2 in fish.

        The reason I posted my original question is because K2 produced these amazing results because of the increased consumption of cheeses, not in spite of them and the more eaten the greater the benefit. This fact has many researchers trying to figure out this paradox of increased cheese and decreased arterial sclerosis, reduced cancers and increased bone health. I’m trying to figure out how to get the good without the bad. I’m not suggesting nor thinking of straying from a vegan diet. Knowing what goes into animal products, as well as not knowing if they were diseased, grosses me out.

        • I know of no good controlled studies concerning improved outcomes with cheese. The studies I am aware of thus far are guilty of confusing correlation with cause or don’t control for all factors. We are hind-gut fermenting herbivores by design so we were designed to get enough vitamin k from plants. As a disclaimer I have not read the studies on K2 vs K1 but a quick pub med search showed only 10 articles on both and none would support some of the benefits you tout. I would stick to the scientific studies. I’m sure if any emerge Dr. Greger will address them.

          • Selina

            Yes, I have also tried to find studies proving anything about the benefits of including this super vitamin X-factor K2 into our diet, and so far I have found none.

            My brother who studies to become a doctor laughed at this and said that vitamin K1 is all that we need because it is converted into K2 in the colon. All sources of vitamin K1 are extremely healthy compared to the sources which have K2 (expect plant sources like non pasteurized sauerkraut, miso, natto and tempeh).
            Green leafy vegetables all the way baby! (one cup of kale provides 525% daily value of vitamin K) I sometimes end up finishing a whole bowl of kale salad because it’s so good.

          • N_

            Does your brother know how much K1 is being converted? I don’t question that some of it does convert, but is the conversion rate really enough?

          • Selina

            I can ask him the next time we meet.

          • N_

            Thank you. I would be more than happy if you also could ask if enough of the beta-carotene from food is converted to Vitamin A the body needs as well. :)

    • MikeZP

      The best source of K2-MK7 is Natto(fermented soy) with is far more better than animal based K2-MK4

      • mbglife

        You’re right, thanks for that reminder. I had forgotten that natto is a good source. I’m allergic to soy, so I must have just forgotten about it over time since it wasn’t something I could consider. But from what I have read, the MK-4 form (cheese and meats) circulates in the blood for only 3 or 4 hours before it’s gone, while the MK-7 from natto can last for 3 days. Some researchers have taken this to mean that the MK-4 form is more bioavailable because of a “rapid uptake”, and that the MK-7 is not able to be used by the body so it just keeps circulating. However, other researchers have concluded that the liver uses or destroys MK-4 and that’s why it doesn’t persist, and that the more bioavailable and useful form is MK-7. The Rotterdam study, to my knowledge, didn’t include natto which produces the MK-7. But other researchers point to long lived Japanese for proof that MK-7 is as good or better. I’m not a researcher and therefore left needed help. There are apparently forms of K2, mostly from different cheeses, that ranging from MK-5, and MK-8 through MK-10 or 11 (I’ve forgotten). So it’s not simple, but potentially very important.

        • Selina

          That is a good question, as this vitamin is not very common naturally.

          But it seems that humans have been fermenting foods since the beginning of time. And many fermented foods have this vitamin, not just natto and cheese. Fermentation has been a very important way to preserve foods, and also has some impressive health benefits. Sauerkraut is a good example of this, it was also a means of preventing scurvy during the winter times in northern Europe.

  • Sideshow

    there nothing wrong with saturated fat and there no studies that prove saturated is bad for you even animal .this very idea that animal fat is bad for is a myth….and there are scientific studies that prove conclusively that saturated fat whether from animal or plant(coconut oil0 is bad for youy.

    • Anna

      but then saturated fat os bad or not bad…there’s a contradiction in your comment…

  • rachel

    Dr. greger, thank you again for such wonderful videos and information about plant healthy diets. I personally have been vegetarian or vegan for 25 years.
    This does relate to vitamin K!. My younger brother, not overweight, has had issues with varicose veins behind his knee and has had one operation there.
    Apparently there is a history of artery issues with men in the family.
    Several months later an MRI found a partially blocked artery in his neck. He
    was in the hospital for several days and of course his doctors put him on Cumadin and Hezadrin. I am sending him information on your site and on plant based diets but he focuses on the drug use and subsequent contraindications to AVOID Vitamin K from so many healthy sources. I understand that foods containing vitamin k are much
    healthier than the drugs and believe a plant diet would change his health
    but he seems to rely on his doctors and the drugs as “necessary’ for him.
    Thank you for your comments, namaste’, rachel

    • The drug coumadin works by undermining vitamin K metabolism, and so if you eat healthy foods like greens that have lots of vitmain K you can undermine the drug’s effects. Doesn’t mean you can’t eat healthy foods you just have to have his physician titrate the dose of the drug to his greens intake and then stick with that dose of drugs and vegetables.

  • Annette

    My nephew had was diagnosed with osteosarcoma of the tibia last year. He had 2 months of chemo, a total knee replacement and a further 6 months of chemo. He has now been diagnosed with a chronic infection and has to have the implant removed, a temporary antibiotic rod inserted for 2 -3 months and then another knee inserted. He has been recommended to have Intravenous Vitamin C to hep reduced the chronic infection and aid his recovery. I am aware of the lack of benefit from oral Vit C but have read some positive information on IV Vit C. I would really appreciate your opinion on the subject? Kind Regards. Annette

  • Jasmine Steers

    Dear Michael, I want to thank you for your FB page. I have used a lot of your information for my own knowledge acquisition in my Nutrition Therapy qualification. But some times I feel like I am a lone tree in a forest….no one wants to listen. I have even ended up arguing with GP’s about milk. It seems a lot of GP’s do not understand nutrition or they refuse to go against current guidelines. I advise teenage girls to avoid cows milk and increase their green leafy vegs instead. Would you advise the same? Thank you for your page! :)

  • superape

    Dear Dr. Greger, on the same Dr. Oz show you appeared in, one of the topics was about too much calcium intake being dangerous, can clog your arteries and cause a heart attack. Is that the same with calcium from plants or can vegans not really overdose on calcium?

  • Mindaugas Raulinaitis

    Somebody please help, I cannot get enough calcium on a plant based diet :( I ditched all milk products and now get maximum 35% of recommended calcium intake (according to, except when I eat at least 75 grams of tofu every day. But how can you get it from sources other than soy, when the amounts of calcium in plants are such minuscule? From broccoli, when 1 cup has 62 mg? Eat 17 cups of broccoli daily? Or 17 tablespoons of tahini (64 mg each)? Or 20 tablespoons of almond butter? Or 15 cups of dried apricots (1/2 cup contains 35 mg)??

    • dogulas

      Get significant amounts of calcium from greens and beans. Boil or steam kale, collard greens, and all those dark green leafies! Eat tons of them, it will only make you super healthy. And lots of beans are rich in calcium. Eat them up and you’ll be fine :)

  • Hello, Dr. Greger! I am a HUGE fan of your work and website. I am currently writing the conclusion work for my bachelor degree in dietetics, which is a book about the science and gastronomy of vegetarianism/veganism. You’ve been a great source for references and discussions, I’d like to congradulate you for that!
    So, my question is: where can I find the bioavailability/absorbability of calcium in dairy and vegetable sources???? I am searching and searching but I can’t seem to find it! If anybody has/knows articles that have these data, I would be very grateful!

  • Committed Nutritarian

    Vitamin K…..Greens…….Vitamin K-1, Vitamin K-2…..
    It seems the research – on some of these issues is in its infancy……..
    But I do think Vitamin K is a truly essential vitamin per se.
    Saw an article about K-2…../needed for strong bones/teeth/prevent – reverse Osteopenia/Osteoporosis…./
    Am hoping someone can enlighten on the Leading edge research about Vitamin K/the need for it/best sources/fresh greens?/Cooked Greens?/Best Greens.

    Thank you,

    David K

  • Soul Kitty

    Hi, Dr G, i would like to hear you discuss K2 in the form of either natto (a fermented soybean dish) or dairy from cows that eat rapidly growing green grass. I have read that humans cannot convert greens into K2 which has the action of funneling calcium into the bones while synergistically, along with Vit D3 and A (from cod), sweeping calcium from arteries where it is causing all of the problems. This is from information from a study done in 2007 and it seems this info has not trickled down to doctors in the field. Since most do not get grass fed K2 rich dairy or meat and we certainly don’t consume natto wouldn’t this deficiency (along with A and D3) explain a lot if not most of the heart disease and osteoporosis we see?

  • Cameron s

    can i have the resources that state calcium in the boy choy, kale, etc is more bio-avaiable please

    • Joseph Gonzales R.D.

      The PCRM link will have a citation. I like their graph! See if that works? Thanks, Cameron.

  • Cameron s

    Dr. Greger

    I saw that this video states that some vegetables are associated with higher bio-avaibility of calcium, then diary products do you by any chance have the sources that i can get this from, i would like to show a friend. I also hope to stay in contact with you throughout my career, I am in my finally stages of my internship as a dietetic student soon to be registered dietitian I would love to work for your website or any other projects that you work on. Thanks

    Cameron Segura

  • Rob Parker

    Dark green leafy vegetables seem to be a good source of vitamin K1. What is a good plant based source of Vitamin K2 and is it important to get both?

    • Joseph Gonzales R.D.

      Dr. Greger addressed Vitamin K2 in his Q & A. See if that helps? Thanks, Rob!

  • Dallas

    The appointment reminder card I received from my dentist recently included the following “Dental Fun Fact”:
    Say cheese! The calcium and phosphorous found in cheese is healthy for your teeth — it reduces the pH level in plaque and re-mineralizes the enamel.
    I did an Internet search for that text and found that it’s very common on dentist’s web sites and even on some Wisconsin (aka the Dairy State) K-12 school web sites — always with the “phosphorous” misspelling and the hyphenated “re-mineralizes”.

    Do you know the origin of this “Fact” and whether it’s actually true or just some unfounded American Dairy Association propaganda?

    • Joseph Gonzales R.D.

      Not sure? Do they provide a reference? Post any links or information you have and I’ll try to look into it. Thanks, Dallas.