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Resolving the Vitamin D-Bate

Why the current vitamin D recommendations may be too low, other expert recommendations may be too high, and 2000 international units a day may be just right.

December 14, 2011 |
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Supplementary Info

Resolving the Vitamin D-Bate, 5.0 out of 5 based on 5 ratings

Sources Cited

Heaney RP, Armas LA, Shary JR, Bell NH, Binkley N, Hollis BW. 25-Hydroxylation of vitamin D3: relation to circulating vitamin D3 under various input conditions. Am J Clin Nutr. 2008 Jun;87(6):1738-42.

Acknowledgements

Image thanks to plant nutrition.

Transcript

Is there a way we can ask the body how much vitamin D it wants overall? Scientists came up with two ways. First, let’s say you give a whopping dose, and I mean whopping, 100,000 IUs, something that could be toxic if done on a daily basis. The question is, what’s your body’s saturation point. Of this massive dose much does your body actually use, and how much does it sock away in storage at for use later on down the road? Here’s the graph; 30 people followed for 4 months after the megadose. Here’s the flood of D coming into their system, but the solid circles represent the pool of vitamin D our body is keeping in our blood stream for activation, and the rest is likely stored away to be used on an as needed ongoing basis. Note that in this setting of abundance the body is keeping our levels right around that sweet spot dip found in the U-shaped mortality curve.
You can do the same thing at the other end of the spectrum too. Instead of a megadose you can start by giving really tiny doses and gradually work your way up. When you do you get a graph like this showing a so-called biphasic pattern, really steep at first, but then leveling out.
When you take in just a little bit, your body zips it into circulation, desperately needing it. But then as you increase the dose, at a certain point you kind of turn the corner when the crisis is averted, your body seems happy enough with your levels that as you take more your levels still rise, but it’s not such an emergency.
Now if this plateau was flat, completely horizontal there’s be no risk of toxicity, but because your body can’t help but let some in, your levels continue to rise with increasing intake and you can run into vitamin D toxicity problems if we take too much. But what’s this level here, right at the corner, when your body takes a big sigh of relief that you’re doing pretty good on vitamin D?
Working in from both ends, the level at which your body appears satisfied translates to about 2000 IUs a day, which should get us right into that U-shaped longevity sweet spot, whereas the Institute of Medicine recomendatiosn appear too low, and the 10,000 recommendations put forth by others appears too high.

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 volunteer@nutritionfacts.org

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. This is the 8th video in a nine day series on vitamin D. Be sure to check out yesterday's video-of-the-dayHow the Institute of Medicine arrived at their vitamin D recommendation.

For some context, please check out my associated blog posts: Vitamin D: Shedding some light on the new recommendations and Eating To Extend Our Lifespan.

  • http://nutritionfacts.org/members/mgreger/ 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. This is the 8th video in a nine day series on vitamin D. Be sure to check out yesterday’s video-of-the-day How the Institute of Medicine arrived at their vitamin D recommendation.

  • http://nutritionfacts.org/members/dgmusselman/ dgmusselman

    Thanks for the comprehensive info. re: vit. D. I’m still unsure, however, about which form of D supplement is effective–D3(nonvegan) or D2(vegan). I’ve even seen ads for vegan D3. Over the last 3 years I’ve seen conflicting reports about the effectiveness of D2? Can you clarify?

    • http://nutritionfacts.org/members/mgreger/ Michael Greger M.D.

      Taken daily in doses at 2000IU or less, 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).

      • http://nutritionfacts.org/members/toxins/ Toxins

        I take 2400 daily, is this too much?

        • http://nutritionfacts.org/members/mgreger/ Michael Greger M.D.

          Nope, the current upper daily limit is 4,000 (though more likely 10,000).

          • http://www.facebook.com/profile.php?id=688695468 Cyclo Uten Etternavn

            I’ve found a affordable supplement, however the dosage is 5000 IU per capsule. Would you consider this as too much, Michael? 

          • DrDons

            If you decide you should take a supplement remember that Vitamin D is stored so if you were to take your 5000 IU every other day you would average 2500/d. I think caution is in order especially with supplements which can be toxic. Also cautionary is the study showing that taking isolated supplements Beta Carotene, Vitamin A & E lead to increase morbiditiy and mortality see http://nutritionfacts.org/video/antioxidant-vitamin-supplements/. The best recommendation is to get your Vitamin D from sunlight. It would not surprise me if future studies show that there are other factors that our bodies make with exposure to sunlight that are helpful… time will tell. So I would recommend factoring in your location and amount of sun exposure you get to your decision whether to take supplements and how much to take see http://nutritionfacts.org/video/vitamin-supplements-worth-taking/. Keep tuned as new scientific studies shed light on these complex issues.

  • http://nutritionfacts.org/members/struzjunkatt-net/ Ted

    Thanks for the awesome website!
    So I’m assuming that the suggestion of 2000 IUs/d to hit the “sweet spot” are the total IUs of vitamin D/d, meaning from all sources such as supplements, food, and sun. Is there a correction factor to apply to 2000 IU/d to account for sun at various latitudes and times of the year? (For example, Denver, CO — Summer versus Winter.)

    • http://nutritionfacts.org/members/struzjunkatt-net/ Ted

      So I watched the videos in reverse order a saw that there’s no “one-size-fits-all” correction factor. Guess I’ll just shoot for 2000 IU/d in the Winter and less if I’m getting some sun.

  • http://nutritionfacts.org/members/joyzakarian/ JoyZakarian

    Hi Dr. Greger,

    Is the 2,000 IU/day recommendation the same for vegan Vitamin D2? I thought one of your articles in a previous video explained that they aren’t exactly equivalent. Thank you!

    • http://nutritionfacts.org/members/mgreger/ Michael Greger M.D.

      Same recommendation Joy–see my response to dgmusselman above.

  • http://nutritionfacts.org/members/dave23/ dave23

    Thanks for the this informative video. Aren’t there other health benefits from the sun that we can’t get from supplements?

    Also, if I live on the east coast and get pretty much zero sun during the winter should I just take vitamin d or should I get tested because perhaps I have enough stored from previous sun and/ or from mushrooms?

  • Michael Greger M.D.

    For some context, please check out my associated blog post Vitamin D: Shedding Some Light on the New Recommendations!

  • Sheri O

    Are your recommended levels the same for children as they are for adults?  

  • Marek Záda

    I have read a number of articles on vitamin D and dundruff. I suffer from dundruff for over 10 years, no shampoo really cured my scalp. However, when I go for vacation – usually nearby sea during summer time, dandruff almost disappears within a week. I never thought of vit. D deficiency as I never had a broken bone (yet live an active lifestyle). I live in central Europe and am an office rat, lack of sun exposure is quite common in my case. I concluded that a weekly safe tube tanning might be a good way how to get D3 they way we are supposed to. Your opinion on the matter?

  • Julia

    I just discovered that Magnesium supplement helps/cures not only my newly revived muscle cramps, but also longstanding insomnia. Foot cramps (usually at night) arose after taking 2000IU/d Vitamin D for a few weeks. I read a story about a woman whose serum D levels didn’t go up with supplementation until she also took magnesium. Apparently it takes a good bit of Mg to convert the D to its usable form. Did any of the research on optimal D supplementation levels take Mg levels or intake into account? BTW, I’ve been eating nutrient dense whole plant food, lots of greens, for going on 6 years. Still I noticed if I skipped more than a day or two eating spinach, I’d get the leg and toe cramps. Wondering if i need less D when i get enough Mg. I am 61y.o. female. Thanks!

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