Fat Soluble Vitamins: Do They Stand Between Vegans and Health?

Fat Soluble Vitamins: Do They Stand Between Vegans and Health?

By | 2011-06-20T12:33:48+00:00 June 20th, 2011|Tags: , , , , |59 Comments
This month, I’m working on a couple of responses to recently published criticisms of vegan diets. Among the issues that are frequently raised is one that focuses on fat-soluble vitamins. Some of the concerns are based on legitimate questions about active forms of these vitamins and their absorption from plant foods, and others aren’t. Regardless of those questions, though, plant foods can and do provide enough of the fat soluble vitamins A, D and K. (Vitamin E, which is also fat-soluble, is not involved in the controversy since it’s found in a very wide variety of foods.)
Vitamin A: It’s true that the preformed active type of this vitamin is found only in animal foods. But plants are abundant in vitamin A precursors like beta-carotene. In fact, these provitamin A compounds are important enough that the USDA measures vitamin A content of foods as “retinol activity equivalents (RAE),” which includes both preformed vitamin A and the compounds that the body turns into vitamin A. There is no separate RDA or recommendation for animal-derived pre-formed vitamin A.
You can meet your vitamin A requirement for the day by drinking just one-quarter cup of carrot juice or eating a cup of kale or spinach. Other foods that make significant contributions are sweet potatoes, cantaloupe, and dark orange winter squashes, including pumpkin. A word of caution though: Earlier assessments of retinol activity equivalents in plant foods over-estimated amounts. This is because more recent data show that conversion rates of the vitamin A precursors are lower than previously believed. As a result, vitamin A is a nutrient that deserves some attention in vegan diets. This doesn’t mean you can’t get enough; it does mean that it’s a good idea to make sure you eat vitamin A rich foods every day.  
Vitamin D: This vitamin occurs naturally in only a few foods—fatty fish, eggs from chickens who were fed vitamin D, and mushrooms treated with ultraviolet light. With such limited dietary availability, humans wouldn’t have gotten very far if not for the fact that we can make all the vitamin D we need when skin is exposed to sunlight.  As humans have moved farther from equatorial zones—and spend less time outdoors—it’s become harder to make enough, though, so vitamin D-fortified foods have become important.
Although people can get adequate vitamin D from fatty fish, most—omnivore or not—rely on fortified foods and sun exposure, two options that are as easily available to vegans as to omnivores.
The vegan form of vitamin D, which is called ergocalciferol or vitamin D2, has been shown to be as effective in raising blood levels of this nutrient as animal-derived vitamin D3 when it’s taken at a usual daily dose (1) (The RDA is 600 IUs; some experts recommend 1,000.) At megadoses, however, vitamin D2 may need to be taken more often.(2) But no one should be megadosing on vitamin D unless they are working with a doctor to correct a deficiency. And vitamin D2 has been used to effectively raise blood levels in people with deficiencies. (3, 4)
Vitamin K: Best sources of this nutrient are leafy green vegetables and canola, soy and olive oils. One form of vitamin K, called vitamin K2 or menaquinone, is found in animal products but in only one lone plant food—natto, a fermented soy product that isn’t a usual part of most western vegan diets. This isn’t a problem, though, because humans have no requirement for vitamin K2. We also have bacteria in our gut that produce this form of vitamin K—so we’re covered either way. Since vitamin K is essential for blood clotting we’d see some evidence of a deficiency if vegans weren’t getting enough. But a study that compared clotting rates between vegans and meat eaters found no difference. (5)
Getting Enough of the Fat Soluble Vitamins: The best way to make sure you’re getting adequate amounts of the fat soluble vitamins is to eat plenty of leafy green and dark orange vegetables and to take a vitamin D supplement if you don’t get adequate sun exposure. Gentle cooking improves the absorption of some vitamin A precursors, and cooking foods in small amounts of olive or canola oil can give you a vitamin boost while improving absorption of these vitamins.
1.            Holick MF, Biancuzzo RM, Chen TC, et al. Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D. J Clin Endocrinol Metab 2008;93:677-81.
2.            Romagnoli E, Mascia ML, Cipriani C, et al. Short and Long Term Variations in Serum Calciotrophic Hormones after a Single Very Large Dose of Ergocalciferol (Vitamin D2) or Cholecalciferol (Vitamin D3) in the Elderly. J Clin Endocrinol Metab 2008.
3.            Thacher TD, Obadofin MO, O’Brien KO, Abrams SA. The effect of vitamin D2 and vitamin D3 on intestinal calcium absorption in Nigerian children with rickets. J Clin Endocrinol Metab 2009;94:3314-21.
4.            Gordon CM, Williams AL, Feldman HA, et al. Treatment of Hypovitaminosis D in Infants and Toddlers. J Clin Endocrinol Metab 2008.
5.            Sanders TA, Roshanai F. Platelet phospholipid fatty acid composition and function in vegans compared with age- and sex-matched omnivore controls. Eur J Clin Nutr 1992;46:823-31.


  1. beforewisdom June 20, 2011 at 3:08 pm - Reply

    A friend of mine recently got her vitamin D levels tested.   It was low despite taking several thousand IUs of D-2 a day.   She took that much because other vegan nutrition experts have told her that D-2 ( vegan vitamin D ) doesn't get absorbed as well as D-3.   I am impressed that you have 4 citations that say D-2 works.   Was my friend just taking too much or are some people anomalies, with special needs?

    • Ginny Messina June 20, 2011 at 6:26 pm - Reply

      I don't know. I've heard anecdotal reports here and there from vegans who say that they have had trouble raising vitamin D levels with D2, but the research suggests it's not a problem. But yes, there's certainly a range of needs and some handful of people will need much more than the RDA. Was your friend deficient at some point? Because it can take a very long time to bring vitamin D levels back up, regardless of the type being used.

      • beforewisdom June 21, 2011 at 4:12 am - Reply

        I don't know.  Are there any figures for how long it takes Vitamin D levels to build up after a deficiency?

        • Ginny Messina June 21, 2011 at 9:48 am - Reply

          I'll have to look to see if any of the experts give a range for this. I only know that it can take many months before levels start to rise. There is also some evidence that it's important to be consistent in taking vitamin D supplements, so that could be a factor, too.

          • Brandon Becker July 4, 2011 at 2:08 pm

            This past February, I had my blood tested and was slightly low vitamin D levels as I always wear sunscreen when I’m going to be in the sun for long as I burn easily and hadn’t been consistent about taking vitamins. I was instructed by my doctor to take 2,000 IU of vitamin D for the next two weeks and then have a retest of my blood. Rather than take just 2,000 IU D2 for the next two weeks, I took 4,000 IU at the start, 3,000 for the next few days, and 2,000 for the last week, and my blood level of vitamin D was back to normal on the retest. I now take 1,200 IU vitamin D2 each day from supplements. I’ll see what my blood levels are next year and will likely cut down to 800 IU per day (from supplements, I get more from fortified foods) if everything is still normal.

      • Another vegan December 25, 2015 at 6:48 am - Reply

        Some people who have problems with fat metabolism will have trouble absorbing the available fat soluble nutrients (examples include gallstones, an exceedingly common occurrence that often goes undetected, or those who have had their gallbladders removed, or those with other forms of biliary or liver dysfunction). Essentially, this usually boils down to a malabsorption issue, not the form of the vitamin (aka D2 vs D3 or beta carotene vs vitamin A).

  2. Linda June 20, 2011 at 5:05 pm - Reply

    I have tried a few ways to cook kale, collards and Swiss chard, but can't say I'm a 'fan' of them.  I do like spinach (prepared in any way) and beet greens, lightly sauteed with garlic.  Question: what are your thoughts on 'green smoothies' with raw kale, etc?  This seems like a painless, and possibly pleasant, way to get your greens first thing in the morning for a leg up on nutrition for the day.  I've resisted the whole smoothie trend, since I prefer chewing my calories, instead of drinking them, but I'm flexible. 

    • Ginny Messina June 20, 2011 at 6:28 pm - Reply

      I think smoothies can be a good way to get more greens into your diet. Kale probably works the best in them. And be sure to add something with a higher fat content–some nuts or seeds or a little oil or tofu or avocado–to boost absorption.

  3. Name (required) June 21, 2011 at 3:46 am - Reply

    Unfortunately, you have not addressed the claim that due to genetic variations, many people may not be able to convert pro-vitamin A carotenoids in sufficient amounts:

    • Ginny Messina June 21, 2011 at 10:10 am - Reply

      And neither did the Institute of Medicine in specifying requirements for RAEs. Nutrient recommendations always have a safey factor built in to cover the variability in individual metabolism.

  4. Camille Contreras June 21, 2011 at 4:41 am - Reply

    As you're talking about kale; a few days ago, I attended a lecture by a dietitian (at the Oslo Vegetarfestival: http://www.oslovegetarfestival.no/program – the lecture was by Dr. Pernilla Karlsson (http://www.veganlife.se/)) and she said that children under 1 year old should not be given green leafy vegetables, as they don't have the enzymes to digest them. I had never heard of that before; so I'd like to know what you think about it.
    Also, about B12, she said that one should take methylcobalamin, that it was more efficient than cyanocobalamin. She said that it was because cyanocobalamin never occurred in nature, that it was a synthetic form of B12; whereas methylcobalamin was a biological form; she also said that the cyanocobalamin ingested was converted into methylcobalamin in the organism anyway. I was a bit confused, as I've always read that cyanocobalamin was a better choice than methylcobalamin; and that the dosage requirements could be much higher for methylcobalamin than cyanocobalamin. What do you think?

    • Ginny Messina June 21, 2011 at 10:17 am - Reply

      Camille, the recommendation is to avoid giving infants leafy greens, carrots, turnips, or beets before the age of 4 months because these foods all contain nitrates which can cause a red blood cell disorder. But after the age of 4 months, it's fine to feed these foods to infants.

      As for B12, I recommend cyanocobalamin because almost all of the research has used this form of the supplement. There is some evidence that methylcobalamin is less stable and therefore effective doses may be much, much higher. Without any good data on this, I'm reluctant to recommend it.

      • Mandy November 24, 2013 at 12:35 pm - Reply

        Hi, just wondering if 2 years+ later, this is still your recommendation… I was amazed to read this as methylcobalamin has gained popularity as being the far superior B12 form. I am also a heterozygous MTHFR case, so I take 5000 methylcobalamin daily.

  5. Michael Chelnov June 21, 2011 at 5:06 am - Reply

    I have a question about  D2 vs D3. I have been a vegetarian for 40 years.  (I realize I'm a little out of place here) In winter I take a D3 supplement from Source Naturals (1000 I.U.) I understand that it is derived from the lanolin in sheeps wool. presumably derived from the wool of sheared sheep. It has a very good effect on my sleep and mental acuity. Do you know if  the D3 is really derived from  the lanolin of the sheared wool….as opposed to something less life supporting….? 

    • Ginny Messina June 21, 2011 at 10:21 am - Reply

      It almost always comes from lanolin from sheep's wool or from fish oil. At any rate, vitamin D3 is always animal derived and usually the product of factory farming. And you're not out of place here; there are plenty of non-vegans who read this blog and all are welcome!

      • Linda June 24, 2011 at 4:20 pm - Reply

        Now where’s that ‘Like’ button when you need it!

    • TaVe June 16, 2012 at 8:16 pm - Reply

      You can get vegan D3 nowadays. http://www.veganstore.com/category/s?keyword=D3

      But if it doesn’t say vegan, its going to be from animals.

  6. Daisy June 21, 2011 at 7:06 am - Reply

    Interesting article. Why do you think the Endocrine Society recommends D(3) over D(2)?
    "Vitamin D3 (cholecalciferol) is the form of the vitamin absorbed through the sun. It is superior to the synthetic Vitamin D2 (ergocalciferol). We highly recommend that anyone shopping for a Vitamin D supplement check the label in order to ensure it is D3 and not D2."

  7. Tracy H. June 21, 2011 at 9:44 am - Reply

    That's interesting — I'd never thought to put tofu in a smoothie.

  8. Robert June 21, 2011 at 1:16 pm - Reply

    My doctor recommended 2000 IU of vitamin D but didn't specify between D2 or D3. I have read, in my travels, that D2 isn't as easily absorbed as D3 so if you take D2 you need to increase the dosage. If you're fortunate to have a nice strong sun shining down on you most of the year this isn't an issue. I live in Canada and supplementation is highly recommended.

    • Ginny Messina June 21, 2011 at 1:21 pm - Reply

      Robert, I live in the Pacific Northwest so vitamin D is a concern for me, too. There is a lot of debate among the experts about how much vitamin D is really needed for people who don't get much sun exposure, and 2,000 IUs is not an unusual recommendation at all.

      The issue about vitamin D2 isn't absorption, though. It really does seem to be absorbed as well as D3. However, in studies that use megadoses of it, blood levels start to drop more quickly after taking D2 compared to D3. For people taking moderate amounts–and 2,000 is a moderate amount–and taking it every day, this shouldn't be an issue.

      • Robert June 21, 2011 at 5:06 pm - Reply

        I believe the safe upper limit to be around 4000 IU. Does that sound correct?

        • Ginny Messina June 21, 2011 at 6:45 pm - Reply

          Yes, 4,000 IUs is the upper limit.

  9. myvegancookbook June 21, 2011 at 6:39 pm - Reply

    I’ve been hearing a few Doctors, like Dr. Weil, recommending eating more hard cheeses because they are rich in vitamin K2, which helps prevent cancer. This of course flies in the face of T. Colin Campbell’s research. I’m thinking of adding nato to my diet but I read it smells like, excuse my language…A#$ lol

  10. Ginny Messina June 21, 2011 at 6:47 pm - Reply

    Are you sure Dr. Weil says that? I couldn’t find anything in his vitamin K recommendations that refers to K2. I don’t think there is much research to support any relationship of cheese to cancer risk–either for or against.

    And I agree with you about natto! It’s the texture that I can’t deal with. But that’s a cultural thing I guess since I believe it’s pretty popular in Japan.

  11. myvegancookbook June 21, 2011 at 6:59 pm - Reply

    I saw Dr. Li on Oz the other day talking about hard cheeses. Here is a link: http://healthybodydaily.com/dr-oz-cancer/dr-oz-gouda-cheese-can-reduce-cancer-risk-three-secret-weapons-to-prevent-cancer

    I’m pretty sure it was Dr. Weil I saw on Martha Stewart a year or so ago recommending hard cheeses. I could be wrong.

    • Ginny Messina June 21, 2011 at 7:16 pm - Reply

      That’s really interesting. I did a quick search of the medical research database for studies on “cheese vitamin K cancer” and only one study came up. It was an epidemiological study (which finds only associations, not cause and effect) and, although it found a link between vitamin K2 (as found in hard cheese) and decreased cancer risk, the results weren’t statistically significant. So I guess we don’t need to start eating hard cheeses! Thanks for the link to this info–I’m going to follow up on Dr. Weil to see what he says about all of this.

  12. myvegancookbook June 21, 2011 at 10:16 pm - Reply

    Dr. Mercola on Vitamin K2: http://www.youtube.com/watch?v=8ePU5NiRDSM
    To me Dr. Mercola seems too eager to sell you supplements.

    An interview with Cees Vermeer PhD. (top vitamin K2 resarcher of the world) conducted by Dr. Mercola. http://www.youtube.com/watch?v=WTm95J8SNGo&feature=related

    There is the Rotterdam Study: http://jn.nutrition.org/content/134/11/3100.full

    Lastly, Dr. Weil on K2: http://www.drweilblog.com/home/2010/4/25/vitamin-k-and-cancer-risk.html

    In his blog he does not mention hard cheeses but on the show I saw him on, he did.

  13. Jennifer June 22, 2011 at 4:42 am - Reply

    It seems that more and more research confirms that vegan diets are safe and beneficial. Eat a large and wide variety of plant based foods, take multivitamins and other specific vitamins when needed, and get outside and take in some sun and exercise. Why is everyone complicating this so much?

  14. Michael June 22, 2011 at 5:47 am - Reply

    Hi Ginny!

    The Company “Garden of Life” sells raw, vegan supplements called “the vitamin code”. And they have a D3 that is harvested from small organisms like yeast and certain forms of bacteria. Do you know them?
    So we can ingest D3 and not needing animals. I really like their products


  15. The Healthy Librarian June 25, 2011 at 5:12 am - Reply

    Thank you, Ginny for your excellent review of the fat-soluble vitamins.

    I value your expert research-based “myth-busting reviews”–and I appreciate the time you put into replying with factual information to every comment. Thank you for all your work!

    Perhaps this bit of advice, based on Dr. Angelo LIcata’s research at the Cleveland Clinic will be of interest. Take your vitamin D with your largest meal of the day–preferably one that has the most fat. It will make a big difference.

    “In our practice, it is common to see patients treated with vitamin D supplements who do not achieve an appreciable rise in their serum 25OHD level after therapy despite large prescribed doses.

    A consistent increase of 50% or greater was seen in the serum 25OHD concentration when patients consumed the vitamin with the largest daily meal.”

    -Drs. Angelo Licata, MD, PhD. and Guy B. Mulligan, MD., Cleveland Clinic Foundation Metabolic Bone Clinic, “Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D”, J Bone Miner Res 25(4):928-30, April 2010-

    To read a detailed summary of the study: http://www.happyhealthylonglife.com/happy_healthy_long_life/2010/03/vitamin-d-at-dinner.html

  16. point.blank July 1, 2011 at 2:27 pm - Reply

    There is virtually no reason to be talking about D2 vs D3 anymore. Natures Plus has a new vegan D3 supplement on the market called Source of Life Garden™ Vitamin D3.

    “The first plant-source cholecalciferol, from a blend of eight different organic mushrooms”

    You can contact them for more information on the process used with which they were able to isolate D3 from Mushrooms..

    The Garden of Life D3, contrary to what the company used to claim, is not vegan.
    It is made from feeding lanolin to yeast and you end up ingesting both.

    The vegan community really needs to accelerate the pace of learning about what’s going on out there if we are to be taken seriously.

    • Ginny Messina July 1, 2011 at 2:53 pm - Reply

      The vitamin D in mushrooms is ergocalciferol or vitamin D2. There is currently a process for making non-animal sourced vitamin D3 but it’s a semi-synthetic process using petrochemicals, according to an article on the Vegetarian Resource Group website. I believe it’s being used only in animal feed, and anyway, it doesn’t sound like what Nature’s Plus is using. There are some types of vitamin D3 that are grown in culture, but they always start out with cholesterol, which is a building block of vitamin D3. So I’m not convinced about the D3 in this product being vegan.

      • point.blank July 1, 2011 at 3:50 pm - Reply

        Only one way to know if it is legit. Contact Mr. Avila @ 631-293-0030 . I look forward to hearing how the conversation went!

      • Ariann July 4, 2011 at 12:39 pm - Reply

        That is really a bummer! I have been taking Source of Life D3 for the past month and a half. My D levels rose only about 10% over two months taking D2 and then rose over 50% over just a month taking the D3 (so finally not “deficient”).

  17. […] Fat Soluble Vitamins: Do They Stand Between Vegans and Health? […]

  18. Joey August 19, 2011 at 12:52 pm - Reply

    There is no chance that Source of Life is actually Vitamin D3. I know for a fact Mushroom can only contain Vitamin D2.

    However, exciting news from the vegan society……………………..

    Vitashine is a new totally vegan vitamin D3: http://www.vitashine-d3.com.

    Proven data, unlike the vague (fake) mushroom stories.


  19. Vitamin D Supplements September 13, 2011 at 5:47 pm - Reply

    […] is getting each day. As long as you are sure to do this correctly, you are going to benefit from it.Vitamin D supplements can help to replenish the amount of vitamin D, which is a group of fat soluble…are exposed to sunlight, which means that sunlight might be an important part of your vitamin D […]

  20. Egon February 2, 2012 at 12:41 am - Reply

    I’m still gray here. Some say that I literally cannot absorb fat soluble vitamins unles I take some oil with them. Is it true that if I eat up a bowl of salad, these vitamins simply go through my body unabsorbed? If I drink a glass of carrot juice, I don’t absorb any vitamin A or K?

  21. silvina April 26, 2012 at 5:21 am - Reply

    The problem with veganism is… these are fat… FAT-soluble vitamins. You not only need the vitamin, but the animal fat to process and absorb it. So where do you get the fat from to absorbe these vitamins if you are a vegan?

    • Ginny Messina April 26, 2012 at 7:18 am - Reply

      Yes, you need fat to absorb them. But it doesn’t matter whether it’s fat from plants or animal products.

  22. […] written before about animal products versus plants for vitamins D and A. Vitamin D is very poorly supplied by foods and although you could technically get enough from […]

  23. vegangsterARNP June 2, 2012 at 8:50 pm - Reply

    Hi. Low vitamin D has nothing to do with being vegan. It has to do with being a human who lives very far from the equator, where the optimal amount of sun hits the skin, and is absorbed, to cause the melanocytes to make vitamin D. If vitamin D was a problem for vegans, well, why is it in every store all over the western world, considering vegans are an extreme minority?

    Vitamin A; nobody has to be concerned with this unless they do not eat a carrot or two now and again, or some dark green leafy vegetables. Not an issue, period.

    Vitamin K? Well, again, as you said, leafy dark vegetables.

    I am so sick about the fact that instead of looking closely at what people are poisoning themselves with by eating animal cadavers, and animal breast milk, they instead spend their time trying to scrutinize the plant based diet, and to nitpick about vitamins, minerals, and things most of these laymen know nothing about. (funnily enough, solely in order to justify their own pleasure of eating these flesh and animal products, which is a complete fallacy)

    • vegangsterARNP June 2, 2012 at 8:59 pm - Reply

      Darn, I forgot to ask you about something:

      Today my partner put up her kale chips recipe on FB. Soon after, she gets a comment from a person eating a “paleo” diet, who has not studied the discipline of either health and well being, or nutrition, and she says that my partner should use oil when making the kale chips in the oven, because she needs the fat intake at the same time in order to absorb fat soluble vitiamins in the kale???!!! All the kale chips have are bit of lemon juice, tiny bit of water, sprinkled nut. yeast, garlic powder, onion powder, salt, and baked for half an hour.

      Can you please explain this nonsensical comment? So, are people eating a paleo diet convinced that every time a person eats a vegetable, they need to think about the vitamin type; water or fat soluble, and eat fat every single time? Honestly, these paleo, atkins offshoots are really disturbing to me, and what’s more, these people are giving advice….totally scary.

      So, it’s my understanding that fat soluble vitamins simply means that is how it is taken up… not that you need fat at the SAME time you are digesting the food… Can you please please help me answer this? I just remember reading that fat soluble vitamins were more easily taken up into the cells as the cell has a lipid layer. Please if you have a chance, help me with a very brief answer so I can understand enough to reply to this person without telling her she needs to stop with the fad diets!

      • Ginny Messina June 3, 2012 at 7:48 am - Reply

        Actually, fat soluble vitamins do require dietary fat for absorption and studies show that adding some fat to leafy greens will improve vitamin K absorption considerably. If you use canola or olive oil, there is an extra benefit since they both contain vitamin K themselves. If you’re eating the kale chips with other foods that contain some fat, it doesn’t really matter. But I’d be inclined to rub just a little oil–like a teaspoon–into the kale before baking to make it even more nutritious.

        • Patrick Hurn June 23, 2012 at 9:12 am - Reply

          In this case would the sprinkled nut add enough fat for vitamin K absorption?

          By the way, I’m very new to the vegan way of living and am easing into it slowly. I’ve been predominantly vegetarian for the last couple of years and have found your blog and it’s comments to be a valuable source of knowledgeable information, thank you.

    • Ja August 30, 2014 at 11:43 pm - Reply

      Very well said. You would think all those people have perfect diets, all organic, free range and locally sourced and are in perfect health!

  24. Moonriseprincess October 12, 2012 at 8:28 am - Reply

    Just as someone mentioned up vitamin D deficiency has nothing to do with being vegan. I was severly deficient for 2 years before I went vegan. Now I am slowly improving health wise and my vitamin D level has improved, but only after I became a vegan and taken supplements. I was also becoming very overweight due to the lack of sufficient D levels and as long as I ate a so called normal diet I could not loose the weight and used to be always sick. Since I became a vegan I feel healthier, my moods have improved, I got more energy, I started losing weight and have no more cravings for sweets and fat foods.

  25. Peter November 22, 2012 at 4:09 pm - Reply

    Thanks for all the great info…I’m Interested in the role phytic acid has in restricting mineral intake, as well as the effect of kale on mineral absorption, I have heard both create malabsorption issues which cause bone loss and tooth decay. There is also a lot of stories online of vegan issues with teeth decay…I was drawn to this article to review the fat soluble vitamins for vegans, but would also like to hear how these other issues have been reviewed.. thanks

  26. Tnat July 8, 2013 at 11:32 am - Reply

    “This isn’t a problem, though, because humans have no requirement for vitamin K2.”

    Whoa, whoa, just WHOA! You might want to seriously consider removing that sentence.

    Weston A. Price (even before it was properly labeled as vitamin K2) has demonstrated how important this nutrient is. Chris Masterjohn, Stephen Guyenet, and Kate Rheaume-Bleue have researched K2 extensively, and I can say for sure that it is absolutely essential for humans.

    No, K1 will not suffice. We can only *absorb so much per day (roughly 200mcg), and it is not effective enough at carboxylating the osteocalcin and MGP proteins. The liver will use K1 to activate blood-clotting factors; however, this can be done with MK-4 (K2). MK-4 covers pretty much everything that “vitamin K” is currently known for: activating blood-clotting factors, carboxylating the osteocalcin and MGP proteins, and supporting insulin. (And possibly more yet to be discovered.)

    * The reason we only absorb so much K1 from the diet is intentional. After such a threshold, K1 becomes toxic (as we try to convert some of it to MK-4), since an intermediary substance from this conversion is the toxic menadione, which can harm the liver and red blood cells.

  27. Elisa November 12, 2013 at 12:23 am - Reply

    Hi Ginny,

    I regularly visit your blog, and it feels reassuring that there is someone ‘out there’ with reliable knowledge on vegan nutrition. Now, I do have a question about K2 as well. I’ve read contradictory information: some say K1 intake (and then its conversion into K2) is sufficient, others say that never can be sufficient. Now, I have 2 toddlers, aged 2 and 4, vegan since conception, and I am rather worried about their dental health: I have the impression the enamel – on the upper front teeth – does not look homogenously ‘white’. Instead, I have the impression that it looks ‘crackled’ (lines and spots when looking very closely). Now, I do give them all ‘usual’ supplements (vitamin D, B12, algae oil, also a multivitamin), and they get their fortified drinks. So am I just hypochondric, or could it really be so that they are lacking something because of their vegan diet, and that this something might be vitamin K2? If so: there are natto-based drops available (also capsules and tablets, but with kids, drops are easier): would you recommend supplementing with this, for ‘safety’s sake’? Would these drops be as efficient as the intake of K2 via food? — Your original post on this dates from 2011, but I would think some more research has been published on K2 in the meantime?

    • Ginny Messina November 14, 2013 at 11:36 am - Reply

      Elisa, there is some research interest in vitamin K2 for prevention of osteoporosis, but I don’t think there is nearly enough evidence to make recommendations. And there are no official recommendations for vitamin K2. I’m not recommending vitamin K2 supplements and I don’t take them myself. But if you want to give them to your family, it seems like the natto drops would be fine.

  28. robit mcclain April 30, 2014 at 8:06 am - Reply

    I strongly back Tnat’s post on Vitamin K2 made back in July 2013. K2 is vitally important and the loss of adequate intake due to changes in the western diet in the 20th century has essentially been an extremely harmful large-scale research project. (on top of the gross overintake of Omega 6 fats)

  29. Richard March 29, 2016 at 4:20 am - Reply

    This article does not touch on the primary concern of the title. There is no question but that a properly varied whole plant-based diet provides large quantities of vitamins….the question that should have been addressed in the article is do plants contain enough fat to absorb those vitamins that require fat…
    Talking about adding refined oils is contrary to healthful consumption of whole plant-based products.
    If plants that average 10% fat are not sufficient the next topic to discuss is how much fat of nuts/seeds, coconut and avocado do we need to add?

  30. james benefiel July 5, 2016 at 11:42 am - Reply

    I believe the information on vitamin K2 here is out dated. It has only been since 2007 that K2 was identified as distinctly different than K1 in function although they are chemical cousins. K2 has no clotting function while K1 does function to promote clotting. Also, the human body makes
    only minuscule amounts of K2, and butter, cheese, meat have become
    very low in vitamin K2 since livestock has been converted from grass to grains as feed. K2 derived from Natto ( fermented soybeans) can be obtained as a supplement and is critical for proper calcium utilization in the human body. Deficiency leads to osteoporosis and cardiovascular disease and numerous other serious diseases. Jim Benefiel

  31. Jana November 14, 2016 at 10:07 pm - Reply

    The frequent mention of adding oil is also outdated. ALL oils are bad including olive oil. Better to eat the whole food – olives – rather than the oil extracted from it because studies show oil destroys the endothelial cells in our body and cause our arteries to lose their elasticity. Please update this info on oil!

  32. Stuart June 13, 2017 at 6:57 am - Reply

    Can you please give an update about k 2 ? Because there are some you articles online now talking about its importance even from vegan sources and sites ? Should vegans supplement Thanks

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