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How much vitamin D do you need to take?

Posted on: November 11, 2014   by  John Cannell, MD


One question that has not been fully answered is how much vitamin D is needed to reach a given blood level. An organization in Canada, The Pure North S’Energy Foundation, has recently helped answer that question.

The Pure North S’Energy Foundation uses evidence-based nutritional supplements to prevent chronic diseases. It is Canada’s largest not-for-profit organization focused on primary prevention.

They studied the vitamin D levels of 17,614 healthy adult volunteers participating in a preventive health program. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OH)D levels ranging from 4 to 157 ng/ml. None of the participants had high blood calcium.

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9 Responses to How much vitamin D do you need to take?

  1. Rita and Misty

    John, l look forward to that day! Thank you very much for this article.

  2. [email protected]

    Vitamin D levels continue to drop around the world.
    About 2X more people are vitamin D deficient now than just two decades ago.
    Governments are increasing their Vitamin D recommendations about every decade.
    Dr. Hollick recommended 1000 IU in 2004, but a decade later recommends 3,500 IU
    Incidence of over 30 health problems related to vitamin D has doubled in a decade
    There are a great many reasons for the decreasing vitamin D levels – such as
    – getting less vitamin D from the sun,
    – getting less vitamin D from food,
    – getting less Magnesium needed absorb Vitamin D in the gut
    !0,000 IU of vitamin D is great. I have been having that much for the past 4 summers.
    Note however, vitamin D monotherapy can cause problems – you should also balance your cofactors – example: increase Magnesium and Vitamin K2, and decrease Calcium

  3. D-fiant

    Thanks for your work on this matter.
    The article attempts to give a ‘frame of reference’ by which we can plan our vitamin D supplementation levels.
    There are external factors that also contribute to our ultimate vitamin D blood levels.
    Some of these are –
    • Our co-factors – mentioned above.
    • The seasons
    • Where you live
    • Do you hide from the sun or encourage exposure
    • The various supplement effectiveness
    • Drug interaction – for example; chemo has been seen to down rate vitamin D.
    • Your DNA
    • How long you are taking a supplement and seeking the sun.
    • Other reasons.
    Having said the above; it is an excellent article by which people can start their journey to acquire their targeted vitamin D levels. As they go, they can gain blood tests and ‘fine tune’ their vitamin D management to suit their individual circumstances.

  4. Magic

    I discovered something the last couple of days that surprised and pleased me. I have taken up to 35,000 international units a day for years but kept to a basic 20,000 most of the time. I felt comfortable and healthy with no pain or illnesses. I read some material that caused me to stop entirely for about two months as a test. Our weather got terribly cold and rainy recently. I felt a cold coming..Sneezing and feeling something that I hadn’t felt for years. I took 6000 ius and recovered so quickly I couldn’t believe it. I took 6000 again yesterday. I will be 81 in February.


  5. Laura

    Hi everyone,

    Would like to introduce myself – I am Laura, 46, living in the Netherlands. I discovered I was severely deficient in D last February. 5000 IU/d got me to a level of 40 ng/ml in April (99 nmol/l). In summer, I took less supplements and tried to get as much sensible sun exposure as possible – but when I tested again in August it came back at 35 ng/ml, though we had very sunny weather. Taking again 5000 IU/d or a little more after that, my test last week came back at 40 ng/ml again. It surprised me that my level would still be so low, but after reading this article I realize I am just average.

    Big fan of the VitaminDCouncil – thank you for the great information on this site!

  6. Ron Carmichael

    Rather than a specific dose (ie, 5,000iu daily), I’ve been recommending 1,000iu of D3 daily for each 20 pounds of body weight in the absence of any pathology, with a blood level to follow. Dr. Cannell, your thoughts?

  7. showmeaschematic

    These graphs don’t completely match my experience.

    I test… and have to take 8,000 IU’s per day to get 70 ng/ml . My wife gets 80 ng/ml but she only has to take 6,000 IU’s. My sister is similar to me. From other people I have talked to, there appears to be a lot of variability in response to oral D3, so I would caution about drawing too much conclusion about any individual from these graphs.

    The other thing that occurred to me was from a lecture given by Dr Rheinholdt Vieth, the Canadian Vitamin D researcher from Toronto. ( Youtube ” Vitamin D Toxicity ” ) who showed that it takes about 6 months or more for a fixed daily dose of Vitamin D to reach a steady level in your blood…. so I wonder whether these results allowed enough time for the levels to stabilize out before recording results versus dosage. My suspicions are that they did not, so underestimate ultimate levels.

    For Laura, who changes her dose with the seasons, I recommend you watch this video, since he tells you why you shouldn’t do that… you can actually increase your chance of getting disease, particularly cancer by cycling your levels per studies from Finland. I have heeded his advice and just keep a steady dosage year round.

  8. Laura

    Thank you, showmeaschematic. I just watched the video with Dr. Vieth again, and like it a lot. Actually, he recommends that if you don’t supplement all year around, you had best do it in winter, so your levels even out, which is what I was going for (avoiding large seasonal fluctuations).
    I didn’t know it took 6 months for 25 (OH)D to plateau, that changes things a bit; but I am still raising my intake to 10000 IU/d. Would like to get to 60 ng/ml to see if it improves sleep.
    According to the graph in the above study, that might still not be enough. For me these data are interesting because the participants were Canadians, living at the same latitude as I am.

  9. GHamilton

    I have found that here in Wisconsin 10000 iu is what is needed to get levels in 50-60 ng/ml range.

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