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Omnivore vs. Vegan Nutrient Deficiencies

Average vegan diets tend to be deficient in three nutrients, whereas average omnivores tend to unfortunately be deficient in seven.

September 11, 2010 |
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Supplementary Info

Sources Cited



There is some bad news though, for those trying to eat healthy. Dietary intake studies have shown that vegans, on average, are not getting the recommended daily intake of three nutrients, calcium, iodine and vitamin B12. Using the same criteria though, omnivores are deficient in seven nutrients, calcium, iodine and five others. Still the EPIC Study found this year that vegans not getting enough calcium have increased bone fracture risk. Those getting enough, 600 milligrams a day were fine, but you know it's not enough to just understand intellectually that plant based sources of nutrients are superior. We need to put it into practice. The calcium in kale and broccoli is absorbed nearly twice as well as the calcium in milk but we cut our absorption down to zero if we let our greens rot in the fridge or we never buy them in the first place. It would be nice if we could somehow absorb the nutrients in fruits and veggies just by staring at them in the produce aisle but no, we actually have to eat them.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by veganmontreal.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

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 theother videos on omnivores. Also, there are 1,449 other subjects covered in the rest of my videos--please feel free to explore them as well!

For some context, please check out my associated blog post: Poultry Paunch: Meat & Weight Gain.

  • 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 omnivores. Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

    • Tan Truong

      Dr. Greger, is there a study cited for the deficiencies mentioned at the beginning of the video?

    • Sean P. O. MacCath-Moran

      I’m also trying to locate the source of the study referenced at the beginning of the video (i.e. regarding the different deficiencies in the different diets; do you have a reference for that handy, Dr. Greger?

    • Sean P. O. MacCath-Moran

      I see that there is other activity in this forum from the NF Team, so I thought I might re-ping on this issue. I’ve been including a link to this video in many of my activism efforts supporting a plant based lifestyle, and I’m occasionally questioned on the source of this study (i.e. regarding the different deficiencies in the different diets). I’ve tried to discover it on my own, but have been unsuccessful.

      Throw me a vegan-bone here? =o)

  • Toxins

    Where is the study showing the nutrient deficiencies in the omnivores? I dont doubt they have it as of what they don’t eat but I am trying to gather data in my own personal collection.

  • Kush Patel

    Do you have any study on Lacto vegetarianism and Nutrient Deficiencies 

  • Thea

    This is one of my favorite videos.  The part that is most interesting is the comparison of vegan deficiencies to omnivore.  Like the others, I too am interested in a citation for the study showing the comparative deficiencies of the different diets.  I’m posting here so that I will get an e-mail when the “sources cited” section is added to.  Thanks!

  • David H

    How can we get enough calcium in our diet apart from consuming fortified soy milk?

    • Toxins

      If you are eating lots of greens and beans you will be getting plenty of calcium.

      • mbglife

        I eat a lot of beans and lentils, sometimes cooked from scratch, but often from canned. I noticed on the side of the cans for different brands of beans it says that a serving is only 4% or 6% of the RDA of calcium. I love beans, but not even I could eat enough to get to 100%. I don’t understand the disconnect between the message, which I have heard for years, that beans are high in calcium and the label, which indicates that they are not. Some peg the RDA as low as 2%. Any insight into this discrepancy?

        • Toxins

          The RDA for calcium is set quite high, at 1000 mg. If we achieve 600 mg we will have plenty of calcium and even less then these amounts, between 300-500 will be fine. No matter how much calcium you eat, osteoporosis prevention is highly dependent upon exercise, low sodium intake, low animal protein and adequate vitamin d and k levels. “Under the extreme condition of immobilization, rapid bone loss occurs despite consumption of 1,000 mg (25 mmol)/day of calcium”

          With this in mind, we can boost the RDA for our own needs. We can double the percentages. So although a cup of black beans may only have 5% of the USDA assigned RDA, it will have 10% of our RDA. A cup of cooked kidney beans will have 24% of our RDA, A cup of cooked collards will have 52% of our RDA. If one consumes a high salt, high animal protein diet then these calcium RDA levels should be increased because the body now requires more calcium.

  • Roy

    Are we anatomically and physiologically omnivores or herbivores?

    • Don Forrester MD

      Hi Roy, We are herbivores designed as hind gut fermenters who differ from the great apes in two respects… we have about 4x the volume in our small intestines to aid the intake of starches and we have 3-9X the amount of amylase genes to aid the digestion of starches. Animals who digest plants need adaptions to their intestines as it is harder to digest plants.. they are longer and either modify the fore gut with more than one stomach or the hind gut with modified caecum and/or colon as we have. Of course all of our other anatomical features are consistent with non hunters from our jaws and teeth to the location of our sexual organs… have you ever seen a predator with the sexual organs in the front of their bodies? Be well.

    • Ashish

      Are Humans Designed To Eat Meat?

  • georgina08*

    Hi i am from Australia and i am studying the “healths benefits of a vegan diet for teenagers” for my year 12 research project and struggling to find information. I was wondering if you could help me out please.

    • Tan Truong

      Scour this site. It has hundreds of videos with hundreds of sources cited.

      • georgina08*

        I have looked but cant find any useful ones if you have any useful ones that would great if you could tell me them

    • barbarabrussels

      Perhaps you could try typing mood or acne in the search box above ;-)

  • Nicole Duca

    I have heard that Vegans are also deficient in vitamin A. Is that true and if so what is the best supplement?

  • Lin

    Dr.Greger, what about this info though?
    Dr.McDougall: As long ago as 1978 Paterson wrote in the Postgraduate Medical Journal, “Many official bodies give advice on desirable intakes of calcium but no clear evidence of a calcium deficiency disease in otherwise normal people has ever been given. In Western countries the usual calcium intake is of the order of 800-1000 mg/day; in many developing countries figures of 300-500 mg/day are found. There is no evidence that people with such a low intake have any problems with bones or teeth. It seems likely that normal people can adapt to have a normal calcium balance on calcium intakes as low as 150-200 mg/day and that this adaptation is sufficient even in pregnancy and lactation.

  • FreeAmerica123

    Dr. Greger, I am looking for information from scholarly journals on the topic of: “Are vegan diets safe for children. I am not finding much of anything that says yes or no. Could you please assist me in finding some journals or where I might look for something other than abstract that I do not have to purchase to get this information? I need 6 journals, (3-pro 3-con). Thank You for your assistance.

  • SopranoNatasha

    Dr. Greger, thank you for this wonderful site! I’m enjoying doing diligent research for how best to feed my 7month old and our new family :-) I wish her pediatrician was more knowledgable about plant based nutrition. How do I respond to his concern that there isn’t enough bioavailability of vitamins/nutrients in plants to meet her needs? He specifically mentioned D (she takes D drops), iron and vitamin K. He admitted that we probably know more about this than he does (ha!) but seemed adamant that she would need powdered supplements? He wants to do regular blood work to check her levels. How do I best address his concerns and sound like I know what I’m talking about?

    • Thea

      SopranoNatasha: I recommend taking a look at the following page. This page is from VRG, the Vegetarian Research Group. VRG is well-respected and well-researched. At the bottom of pages from the articles references in the page below, are references to the original research.

      I have only looked at, Feeding Vegan Kids. It was super-good and I highly recommend it. The other articles may also be good.

      I hope this helps.

      • SopranoNatasha

        Thank you, Thea!

  • Joel Adams

    This is a great video to refer people too when they go on about how becoming vegan is so dangerous. However, I, like many others would like to know the source of this study as Google is being no help.

  • uv

    (Why does my comment disappear?)