Dr. Cannell on "How much vitamin D?"

In his most recent Vitamin D Council Newsletter (reprinted in its entirety below, minus clickable links, as Dr. Cannell apparently lost his webmaster and this issue of the newsletter is therefore not posted on the Vitamin D Council website; if you would like to either donate money to the Vitamin D Council or pitch in with help with his website, go to www.vitamindcouncil.com), Dr. John Cannell once again enlightens us with some new insights into vitamin D and its enormous role in health. In this issue, he discusses the role of vitamin D in people diagnosed with cancer (treatment, not prevention).

While cancer is not our focus on the Heart Scan Blog, Dr. Cannell's always insightful comments provide some helpful thoughts for our management of vitamin D doses and blood levels.

Dr. Cannell cites a recent study from vitamin D research expert, Dr. Bruce Hollis:

In the first study of its kind, Professor Bruce Hollis of the Medical University of South Carolina gave all of us something to think about. He asked and answered a simple question: How much vitamin D do you have to take to normalize the metabolism of vitamin D?

Remember, unlike other steroid hormones, vitamin D has very unusual metabolism in most modern humans, called first-order, mass action, kinetics. All this means is that the more vitamin D you take, the higher the 25(OH)D level in your blood, and the higher the 25(OH)D level in your blood, the higher the levels of activated vitamin D in your tissues. No other steroid hormone in the body behaves like this. Think about it: would you like your estrogen level to be dependent on how much cholesterol you ate? Or your cortisol level? (I'd ask the same about testosterone levels but I know men well enough not to ask.) No, the body must tightly regulate powerful steroid hormones through substrate inhibition, that is, if an enzyme turns A into B, when the body has enough B, B inhibits the enzyme and so limits its own production.

Not so with vitamin D, at least at modern human vitamin D levels. Professor Reinhold Vieth was the first to write about this and Vieth's Chapter 61 in Feldman, Pike, and Glorieux's wonderful textbook, Vitamin D (Elsevier, 2005, second edition), is a great reason to buy the textbook or have your library do so. (I'm glad to see Amazon is out of stock of the new ones (someone must be reading about vitamin D) but you can still buy used editions.)

Why would the kinetics of vitamin D be different from all other steroids? Maybe they are not, Hollis reasoned, like Vieth before him. Maybe vitamin D levels are so low in modern humans that its metabolic system is on full blast all the time in an attempt to give the body all the vitamin D metabolites it craves. So Hollis asked, Is vitamin D's metabolism different in populations in the upper end of 25(OH)D levels (a population of sun-exposed people and a group of women prescribed 7,000 IU per day)? Note, the Hollis study is free on Medline, you can download the entire paper on the right hand of the PubMed page below.

Hollis BW, et al. Circulating vitamin D3 and 25-hydroxyvitamin D in humans: An important tool to define adequate nutritional vitamin D status. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):631-634.

If you look at the two graphs, Figures 1 and 2 of Hollis' paper, you find vitamin D's kinetics can be normalized, made just like all other steroid hormones in the body, but you have to get enough sunshine or take enough vitamin D to get your 25(OH)D level above 50 ng/ml, and 60 ng/ml would be better. Then your body starts to store cholecalciferol in the body without much further increase in 25(OH)D levels. The reaction becomes saturable. This is a remarkable discovery and it implies levels of 30 and 40 ng/ml are usually not sufficient. It also implies actual vitamin D levels (cholecalciferol levels), not just 25(OH)D levels, may be useful in diagnosing and treating deficiency. Note, that not all of the sun-exposed individuals or women prescribed 7,000 IU/day achieved such levels. That's because the sun-exposed individuals were tested after an Hawaiian winter and because prescribing and taking are two different things.

In answer to the question, "How much vitamin D should someone with cancer take?," Dr. Cannell advises:
"Take enough to get your 25(OH)D level above 60 ng/ml, summer and winter." In doing so, you will have normalized the kinetics of vitamin D and stored the parent compound, cholecalciferol, in your tissues. In the absence of sunshine, you need to take about 1,000 IU/day per 30 pounds of body weight to do this. A 150 pound cancer patient may need to take 5,000 IU per day, a 210 pound cancer patient about 7,000 IU per day, all this in the absence of sunlight.

Dr. Cannell, no stranger to the resisitance among many practicing physicians unaware of the expanding and robust literature on vitamin D, advises people with cancer that:
In the end, if you have cancer and your physician won't do a risk/benefit analysis, do it yourself. The risk side of that equation is easy. Both Quest Diagnostics and Lab-Corp, the two largest reference labs in the USA, report the upper limit of 25(OH)D normal is 100 ng/ml and toxic is above 150 ng/ml, so 60 ng/ml is well below both. The reason levels up to 100 ng/ml are published normals is because there is no credible evidence in the literature that levels of 100 ng/ml do any harm and because sun worshipers often have such levels. (If you don't believe me, go to the beach in the summer for one month, sunbath every day for 30 minutes on each side in your bathing suit, and go home and have a 25(OH)D level.) By getting your level above 60 ng/ml, all you are doing is getting your levels into the mid to upper range of laboratory reference normals. Little or no risk.



For readers wishing to read the entire text of Dr. Cannell's newsletter, it is reprinted below:

The Vitamin D Newsletter
January, 2008


The January newsletter is coming early as I will be out of touch for awhile. If you remember, the last newsletter was on preventing cancer, not treating it. Below is a sampling of the tragic emails the last newsletter generated:


"Dr. Cannell, I was just diagnosed with breast cancer, how much vitamin D should I take?"

"My mother has colon cancer, how much vitamin D should she take?"

"I've had prostate cancer for four years, is there any reason to think vitamin D would help?"

"Dr. Cannell, my son has leukemia, should I give him vitamin D?"


It's one thing to talk about evidence vitamin D may prevent cancer but something quite different to discuss evidence vitamin D might help treat cancer. I used to think the answers to all the above questions were the same. Like anyone else, people with cancer should be screened for vitamin D deficiency and be treated if deficiency is present. Simple. However, it's not that simple. The real questions are, What are reasonable 25-hydroxy-vitamin D [25(OH)D] levels for someone with a life-threatening cancer? How much vitamin D do they need to take to obtain such levels? Is there any evidence, of any kind, that vitamin D will help treat cancer? The risk/benefit analysis of taking vitamin D is quite different if you are in perfect health than if your life, or your child's life, is on the line.

Remember, unlike cancer prevention, not one human randomized controlled trial exists showing vitamin D has a treatment effect on cancer. By treatment effect, I mean prolongs the lives of cancer patients. However, as I cited in my last newsletter, Dr. Philippe Autier of the International Agency for Research on Cancer, and Dr. Sara Gandini of the European Institute of Oncology, performed a meta-analysis of 14 randomized controlled trials showing even low doses of vitamin D extend life but they looked at all-cause mortality, not just cancer (Arch Intern Med. 2007;167(16):1730-1737). However, some epidemiological studies indirectly address the treatment issue and are quite remarkable. The first are a series of discoveries by Professor Johan Moan, Department of Physics at the University of Oslo, with Dr. Alina Porojnicu as the lead author on most of the papers.

Moan J, et al. Colon cancer: Prognosis for different latitudes, age groups and seasons in Norway. J Photochem Photobiol B. 2007 Sep 19

Lagunova Z, et al. Prostate cancer survival is dependent on season of diagnosis. Prostate. 2007 Sep 1;67(12):1362-70.

Porojnicu AC, et al. Changes in risk of death from breast cancer with season and latitude: sun exposure and breast cancer survival in Norway. Breast Cancer Res Treat. 2007 May;102(3):323-8.

Porojnicu A, et al. Season of diagnosis is a predictor of cancer survival. Sun-induced vitamin D may be involved: a possible role of sun-induced Vitamin D. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):675-8.

Porojnicu AC, et al. Season of diagnosis is a prognostic factor in Hodgkin's lymphoma: a possible role of sun-induced vitamin D. Br J Cancer. 2005 Sep 5;93(5):571-4.

Porojnicu AC, et al. Seasonal and geographical variations in lung cancer prognosis in Norway. Does Vitamin D from the sun play a role? Lung Cancer. 2007 Mar;55(3):263-70.

What Professor Moan's group discovered, repeatedly, is quite simple, whether it be cancer of the breast, colon, prostate, lung, or a lymphoma. You live longer if your cancer is diagnosed in the summer. And it is not just Moan's group who has found this. A huge English study recently confirmed Moan's discovery.

Lim HS, et al. Cancer survival is dependent on season of diagnosis and sunlight exposure. Int J Cancer. 2006 Oct 1;119(7):1530-6.

What do these studies mean? Something about summer has a treatment effect on cancer. Whatever it is, you live longer if you are diagnosed in the summer but die sooner if you are diagnosed in the winter. What could it be about summer? Exercise? Fresh air? Melatonin? Sunlight? Pretty girls? Remember, these patients already had cancer. Whatever it is about summer, it is not a preventative effect that Professor Moan discovered, it is a treatment effect. Something about summer prolongs the life of cancer patients.

Dr. Ying Zhou, a research fellow, working with Professor David Christiani at the Harvard School of Public Health, went one step further. The stuffy Harvard researchers assumed summer worked its magic, not by pretty girls, but by summer sunlight making vitamin D. So they looked at total vitamin D input, from both sun and diet, to see if high vitamin D input improved the survival of cancer patients. Yes, indeed, remarkably. They found that early stage lung cancer patients with the highest vitamin D input (from summer season and high intake from diet) lived almost three times longer than patients with the lowest input (winter season and low intake from diet). Three times longer is a huge treatment effect, a treatment effect that most conventional cancer treatment methods would die for.

Zhou W, Vitamin D is associated with improved survival in early-stage non-small cell lung cancer patients. Cancer Epidemiol Biomarkers Prev. 2005 Oct;14(10):2303-9.

And that's not all, Marianne Berwick and her colleagues, at the New Mexico Cancer Institute, found malignant melanoma patients with evidence of continued sun exposure had a 60% mortality reduction compared to patients who did not. That implies a robust treatment effect from sunlight.

Berwick M, et al. Sun exposure and mortality from melanoma. J Natl Cancer Inst. 2005 Feb 2;97(3):195-9.

I will not list the thousands of animal studies that indicate vitamin D has a treatment effect on cancer as almost all of them studied activated vitamin D or its analogs, drugs that bypass normal regulatory mechanisms, cannot get autocrine quantities of the hormone into the cell, and that often cause hypercalcemia. However, Michael Holick's group found that simple vitamin D deficiency made cancers grow faster in mice. That is, vitamin D has a cancer treatment effect in vitamin D deficient mice. Professor Gary Schwartz, at Wake Forest, recently reviewed the reasons to think that vitamin D may have a treatment effect in cancer.

Tangpricha V, et al. Vitamin D deficiency enhances the growth of MC-26 colon cancer xenografts in Balb/c mice. J Nutr. 2005 Oct;135(10):2350-4.

Schwartz GG, Skinner HG. Vitamin D status and cancer: new insights. Curr Opin Clin Nutr Metab Care. 2007 Jan;10(1):6-11.

Finally, one human interventional study exists. In 2005, in an open trial, Professor Reinhold Vieth and his colleagues found just 2,000 IU of vitamin D per day had a positive effect on PSA levels in men with prostate cancer.

Woo TC, et al. Pilot study: potential role of vitamin D (Cholecalciferol) in patients with PSA relapse after definitive therapy. Nutr Cancer. 2005;51(1):32-6.

So we come back to the crucial question. If you have cancer, how much vitamin D should you take, or, more precisely, what 25(OH)D level should you maintain? We don't know. You can correctly say that definitive studies have not been done and, incorrectly, conclude physicians treating cancer patients should do nothing. I say incorrectly because standards of medical practice have always demanded that doctors make reasonable decisions based on what is currently known, doing a risk/benefit analysis along the way to decide what is best for their patients based on what is known today. If a patient has a potentially fatal cancer, the doctor cannot dismiss a relatively benign potential treatment modality just because definitive studies have not been done, and passively watch his patient die. Standards of care require doctors consider what is known now, using information currently available, perform a risk/benefit analysis, and then act in the best interest of their patient.

Luckily, such doctors recently obtained some guidance. In the first study of its kind, Professor Bruce Hollis of the Medical University of South Carolina gave all of us something to think about. He asked and answered a simple question: How much vitamin D do you have to take to normalize the metabolism of vitamin D?

Remember, unlike other steroid hormones, vitamin D has very unusual metabolism in most modern humans, called first-order, mass action, kinetics. All this means is that the more vitamin D you take, the higher the 25(OH)D level in your blood, and the higher the 25(OH)D level in your blood, the higher the levels of activated vitamin D in your tissues. No other steroid hormone in the body behaves like this. Think about it, would you like your estrogen level to be dependent on how much cholesterol you ate? Or your cortisol level? (I'd ask the same about testosterone levels but I know men well enough not to ask.) No, the body must tightly regulate powerful steroid hormones through substrate inhibition, that is, if an enzyme turns A into B, when the body has enough B, B inhibits the enzyme and so limits its own production.

Not so with vitamin D, at least at modern human vitamin D levels. Professor Reinhold Vieth was the first to write about this and Vieth's Chapter 61 in Feldman, Pike, and Glorieux's wonderful textbook, Vitamin D (Elsevier, 2005, second edition), is a great reason to buy the textbook or have your library do so. [ I'm glad to see Amazon is out of stock of the new ones (someone must be reading about vitamin D) but you can still buy used editions.)

Why would the kinetics of vitamin D be different from all other steroids? Maybe they are not, Hollis reasoned, like Vieth before him. Maybe vitamin D levels are so low in modern humans that its metabolic system is on full blast all the time in an attempt to give the body all the vitamin D metabolites it craves. So Hollis asked, Is vitamin D's metabolism different in populations in the upper end of 25(OH)D levels (a population of sun-exposed people and a group of women prescribed 7,000 IU per day)? Note, the Hollis study is free on Medline, you can download the entire paper on the right hand of the PubMed page below.

Hollis BW, et al. Circulating vitamin D3 and 25-hydroxyvitamin D in humans: An important tool to define adequate nutritional vitamin D status. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):631-4.

If you look at the two graphs, Figures 1 and 2 of Hollis' paper, you find vitamin D's kinetics can be normalized, made just like all other steroid hormones in the body, but you have to get enough sunshine or take enough vitamin D to get your 25(OH)D level above 50 ng/ml, and 60 ng/ml would be better. Then your body starts to store cholecalciferol in the body without much further increase in 25(OH)D levels. The reaction becomes saturable. This is a remarkable discovery and it implies levels of 30 and 40 ng/ml are usually not sufficient. It also implies actual vitamin D levels (cholecalciferol levels), not just 25(OH)D levels, may be useful in diagnosing and treating deficiency. Note, that not all of the sun-exposed individuals or women prescribed 7,000 IU/day achieved such levels. That's because the sun-exposed individuals were tested after an Hawaiian winter and because prescribing and taking are two different things.

So my answer to "How much should I take if I have cancer?" is "Take enough to get your 25(OH)D level above 60 ng/ml, summer and winter." In doing so, you will have normalized the kinetics of vitamin D and stored the parent compound, cholecalciferol, in your tissues. In the absence of sunshine, you need to take about 1,000 IU/day per 30 pounds of body weight to do this. A 150 pound cancer patient may need to take 5,000 IU per day, a 210 pound cancer patient about 7,000 IU per day, all this in the absence of sunlight. And this may not be enough; cancer patients may use it up faster (increased metabolic clearance) and children may do the same due to their young and vital enzymes. Or you may need less, because you get more sun than you think, more from your diet, or because you are taking a modern medicine that interferes with the metabolism of vitamin D. An even easier way to do it is go to a sun tanning booth every day and obtain and keep a dark, full-body, tan. Then you don't have to worry about blood levels but I'd get one anyway, just to be sure it was above 60 ng/ml.

Given what Hollis discovered, given the well-known potent anti-cancer properties of activated vitamin D, given epidemiological evidence that summer extends the life of cancer patients, given a meta-analysis of randomized controlled trials showed that vitamin D prolongs life, given animal data that simple vitamin D has a treatment effect on cancer, and given a patient with a life-threatening cancer, what would a reasonable physician do? Simply let their patient die while muttering something about the lack of randomized controlled trials?

No, they would simply check a 25(OH)D level every month and advise cancer patients to take enough vitamin D or frequent sun tanning parlors enough to keep their level above 60 ng/ml. Toxicity does not start until levels reach 150 ng/ml but if you take more than 2,000 IU per day have your doctor order a blood calcium every month or two along with the 25(OH)D. Both you and he will feel better and because if you have cancer, you are probably taking lots of other drugs and little is known about how modern drugs interact with vitamin D metabolism. By getting your level above 60 ng/ml, all you are doing is getting your level to where most lifeguards' levels are at the end of summer, to levels our ancestors had when they lived in the sun, to levels regular users of sun-tan parlors levels achieve, and most importantly, to levels where vitamin D's pharmacokinetics are normalized.

In the end, if you have cancer and your physician won't do a risk/benefit analysis, do it yourself. The risk side of that equation is easy. Both Quest Diagnostics and Lab-Corp, the two largest reference labs in the USA, report the upper limit of 25(OH)D normal is 100 ng/ml and toxic is above 150 ng/ml, so 60 ng/ml is well below both. The reason levels up to 100 ng/ml are published normals is because there is no credible evidence in the literature that levels of 100 ng/ml do any harm and because sun worshipers often have such levels. (If you don't believe me, go to the beach in the summer for one month, sunbath every day for 30 minutes on each side in your bathing suit, and go home and have a 25(OH)D level.) By getting your level above 60 ng/ml, all you are doing is getting your levels into the mid to upper range of laboratory reference normals. Little or no risk.

What are the potential benefits? It probably depends on a number of things. Did your cancer cells retain the enzyme that activates vitamin D? Many do. Did your cancer cells retain the vitamin D receptor? Many do. If your cancer cells get more substrate [25(OH)D], will that substrate induce the cancer cells to make more vitamin D receptors or more of the activating enzyme? Some cancer cells do both. In practical terms, vitamin D is theoretically more likely to help your cancer the earlier you start taking it. However, no one knows. Certainly there is no reason, other than bad medicine, for cancer patients to die vitamin D deficient. Unfortunately, most do.

Tangpricha V, et al. Prevalence of vitamin D deficiency in patients attending an outpatient cancer care clinic in Boston. Endocr Pract. 2004 May-Jun;10(3):292-3.

Plant AS, Tisman G. Frequency of combined deficiencies of vitamin D and holotranscobalamin in cancer patients. Nutr Cancer. 2006;56(2):143-8.

It is very important that readers understand I am not suggesting vitamin D cures cancer or that it replace standard cancer treatment. Oncologists perform miracles every day. Do what they say. The only exception is vitamin D. If your oncologist tells you not to take vitamin D, ask him three questions. 1) How do you convert ng/mls to nmol/Ls? How many IU in a nonogram? 3) How do you spell "cholecalciferol?" If he doesn't know how to measure it, weigh it, or spell it, chances are he doesn't know much about it.

All of the epidemiological and animal studies in the literature suggest cancer patients will prolong their lives if they take vitamin D. I can't find any studies that indicate otherwise. However, none of the suggestive studies are randomized controlled interventional trials; they are all epidemiological or animal studies, or, in the case of Vieth's, an open human study. However, if you have cancer, or your child does, do you want to wait the decades it will take for the American Cancer Society to fund randomized controlled trials using the proper dose of vitamin D? Chances are you, or your child, will not be around to see the results.


John Cannell, MD
The Vitamin D Council
9100 San Gregorio Road
Atascadero, CA 93422


This is a periodic newsletter from the Vitamin D Council, a non-profit trying to end the epidemic of vitamin D deficiency. If you don't want to get the newsletter, please hit reply and let us know. This newsletter is not copyrighted. Please reproduce it and post it on Internet sites. Remember, we are a non-profit and rely on donations to publish our newsletter and maintain our website. Send your tax-deductible contributions to:

The Vitamin D Council
9100 San Gregorio Road
Atascadero, CA 93422



PS: The Vitamin D Council lost our webmaster. If you want to donate your time to a good cause, know all about maintaining websites, are interesting in keeping up with the latest press about vitamin D, and are willing to do so for free, please hit reply and let me know. We currently have $405.52 in our bank account so we cannot pay you now but may be able to pay you in the future.

Comments (14) -

  • Neelesh

    12/6/2007 3:25:00 PM |

    Dr Davis,
      I'm unable to get Vitamin D3 (cholecalciferol) in India. What is being sold is calcium + Vitamin D3 or Alfacalciferol or Calcitriol (http://en.wikipedia.org/wiki/Calcitriol).
    While I couldn't find much about alfacalciferol, Calcitriol's composition looks very similar to what you describe.  
    I wonder if they are the same.
    -Neelesh

  • Anonymous

    12/6/2007 5:02:00 PM |

    Dr. Cannell's arguments make a lot of sense, but his statement that "If he doesn't know how to measure it, weigh it, or spell it, chances are he doesn't know much about it." would carry more weight if he hadn't misspelled nanogram in the immediately preceeding sentence.

  • g

    12/6/2007 9:48:00 PM |

    I like the Feng Shui or symmetry of 60-60-60-60....

    Actually it's 60-60-60-60-60 if you include Apolipoprotein B...
    (although I know you are achieveing TGs<45!)

    This is great!  Thank you, g

  • TedHutchinson

    12/7/2007 12:21:00 AM |

    Those readers who want to check what the research papers actually said may find the NUMBERS that I have emboldened useful. If you just cut and paste the darker number into the search-box at pubmed it should bring up the right paper.
    Moan J, et al. Colon cancer: Prognosis for different latitudes, age groups and seasons in Norway. J Photochem Photobiol B. 2007 Sep 19 18029190
    Lagunova Z, et al. Prostate cancer survival is dependent on season of diagnosis. Prostate. 2007 Sep 1;67(12):1362-70 17624920
    Porojnicu AC, et al.  Changes in risk of death from breast cancer with season and latitude: sun exposure and breast cancer survival in Norway. Breast Cancer Res Treat. 2007 May;102(3):323-8.17028983

    Porojnicu A, et al.  Season of diagnosis is a predictor of cancer survival. Sun-induced vitamin D may be involved: a possible role of sun-induced Vitamin D. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):675-8. 17229569

    Porojnicu AC, et al.  Season of diagnosis is a prognostic factor in Hodgkin's lymphoma: a possible role of sun-induced vitamin D. Br J Cancer. 2005 Sep 5;93(5):571-4.17229569

    Lim HS, et al.  Cancer survival is dependent on season of diagnosis and sunlight exposure. Int J Cancer. 2006 Oct 1;119(7):1530-6.16671100

    Zhou W, Vitamin D is associated with improved survival in early-stage non-small cell lung cancer patients. Cancer Epidemiol Biomarkers Prev. 2005 Oct;14(10):16214909
    Berwick M, et al.  Sun exposure and mortality from melanoma. J Natl Cancer Inst. 2005 Feb 2;97(3):195-9.15687362
    Tangpricha V, et al.  Vitamin D deficiency enhances the growth of MC-26 colon cancer xenografts in Balb/c mice. J Nutr. 2005 Oct;135(10):2350-4.16177194

    Schwartz GG, Skinner HG. Vitamin D status and cancer: new insights. Curr Opin Clin Nutr Metab Care. 2007 Jan;10(1):6-11.17143048

    Woo TC, et al.  Pilot study: potential role of vitamin D (Cholecalciferol) in patients with PSA relapse after definitive therapy. Nutr Cancer. 2005;51(1):32-6.15749627

    Hollis BW, et al.  Circulating vitamin D3 and 25-hydroxyvitamin D in humans: An important tool to define adequate nutritional vitamin D status. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):631-4. 17218096

    Tangpricha V, et al.  Prevalence of vitamin D deficiency in patients attending an outpatient cancer care clinic in Boston. Endocr Pract. 2004 May-Jun;10(3):292-3.15310552

    Plant AS, Tisman G.  Frequency of combined deficiencies of vitamin D and holotranscobalamin in cancer patients. Nutr Cancer. 2006;56(2):143-817474859

    I just feel so upset that I have been misinterpreting Hollis's paper Circulating Vitamin D3 and 25-hydroxyvitamin D in Humans and been telling people that 100nmol/l was a reasonably safe minimum. Looking again at those figures 1 and 2 I take Cannell's point that it may be better, safe rather than just stopping at 40ng 100nmol/l it may be safer, allow a bigger margin for error, to consider 50-60ng/ml 125nmo/l- 150nmol/l as the range for optimal health.
    It's bad enough taking the flax and suggesting 4000iu/d is safe and reasonable where no sun exposure is possible.
    I suspect I'm going to be even more unpopular suggesting 7000iu may be necessary in some/many cases.

  • Anonymous

    12/7/2007 4:47:00 AM |

    Is there any danger from Vitamin D levels that are close to the upper ends of the 'safe' spectrum?

    A study in India once linked high D levels (89 ng/mL) to  higher incidents of cardiac disease, but that study was a bit iffy.

    Info can be found here: http://www.westonaprice.org/basicnutrition/vitamin-d-safety.html

    Although the reference to the Indian study is buried a bit deep in that page. A lot of info there though.

  • Dr. Davis

    12/7/2007 11:46:00 AM |

    What an excellent summary!

    You can see that data probing the health effects, or detrimental effects of higher levels of vitamin D3 (as 25-OH-vitamin D3) are poorly explored. We aim for a blood level of 50-60 ng/ml and have observed no toxic effects whatsoever. In fact, we've observed positive effects well beyond our expectations.

    Nonetheless, I think that going above 60 or 70 ng/ml is relatively uncharted territory.

  • TedHutchinson

    12/7/2007 5:34:00 PM |

    http://www.vitamindcouncil.com/worst_science.shtml This summary of the Indian research mentioned earlier may help those who are unfamiliar with what is being discussed here.

    The problems associated with standardisation of scores between different assessment records is complex and discussed in this paper. Serum 25-hydroxyvitamin d measurement in a large population survey with statistical harmonization of assay variation to an international standard.
    http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17726070 There was pre-publication full text pdf version online, with some nice charts of UK vitamin d status through the year at the back, but I cannot find it now.

    There is still a problem between different assay methods and lab accuracy as some of the presentations at this conference make clear.
    http://app2.capitalreach.com/esp1204/servlet/tc?cn=asbmr&c=10169&s=20343&e=6950&&
    The http://www.deqas.org/ system for ensuring a world standard.

    While of course we must not totally turn our back on past research we do have to consider whether the levels reported would stand comparision with current standards of assessment.

    While I am not suggesting that anyone should try this at home.
    Safety of vitamin D3 in adults with multiple sclerosis used progressively increasing doses of vitamin D3: from 700 to 7000 microg/wk (from 28000 to 280000 IU/wk). I personally believe Vieth to be an honourable man who would, should adverse events have been record would have  reported them.
    Such very high dose levels are outside of the scope of "NORMAL" vitamin D supplementation but the very fact that when tested, the results have been predictable, does give us confidence thatRisk Assessment for Vitamin D
    http://www.ajcn.org/cgi/content/full/85/1/6 does stand up to scrutiny when tested.

    In order to reach the levels detailed by Hollis in Circulating Vitamin D3 and 25-hydroxyvitamin D in Humans: those particularly living above latitude 37 are going to have to use more Vitamin D than Krispin Sullivan suggests during the winter months when sunlight is unavailable. It's my view that the risks associated with low vitamin d status are higher than the alleged, unproven risks of supplementing with up to 10,000iu/daily though in practice a total intake of 4000 -7000iu appear to be required during the winter when sun/uvb is not an option.

  • Vaughny

    12/8/2007 1:23:00 AM |

    Good material on Vit D.  He mentions monthylu blood calcium tests - how critical is this test if one were supplementing in the 4000IU - 6000IU / day range?  Would Vit K2 help prevent higher blood calcium?

  • Dr. Davis

    12/8/2007 1:26:00 AM |

    Monthly calcium tests are silly. There is absolutely no need for this in 99.9% of people.

    No, vitamin k2 will not prevent a rise in calcium. The worry that vitamin D will raise calcium is, for the extreme majority, unfounded.

  • Mo

    12/8/2007 11:33:00 PM |

    Isn't it actually possible that from a certain level of D upwards, that D keeps calcium from not only getting too low but also too high?

    If your D is low I'd imagine your blood calcium would at first be high or within the upper limits of normal before going on a possible plummet route if your D drops more.

    I guess once D has satisfied your bones, it doesn't over do it and distributes to other needy areas.

  • Thomas

    12/9/2007 9:48:00 PM |

    Will any fat (nuts) have similar results compaired to olive oil?

    How often should blood tests be necessary to test vitamin-d absorption ?

    Coulden't find answers to these questions using Google or Dr. Cannell's web site.

  • Dr. Davis

    12/9/2007 11:07:00 PM |

    I don't know. I suspect they have some effect, but I've not examined it specifically.

    We check our patients every 6 months.

  • buy jeans

    11/3/2010 10:31:11 PM |

    While cancer is not our focus on the Heart Scan Blog, Dr. Cannell's always insightful comments provide some helpful thoughts for our management of vitamin D doses and blood levels.

  • John F Ocel JR

    10/13/2011 5:38:58 AM |

    DR Carnell im a huge fan of you and i know ur very smart and good at what u do and love to help educate people about there health expecially about vitamin d i am 28 years old 290 pounds 5 foot 10 vitamin d defient and have severe hypertention i take tribenzor 40-10-25 mg's in the am and monopril 20mg's in the pm, and b12 sublingual which works wonders for me mentally well anyways since iveb been taking bob barefoots coral calcium and vitamin d 3 my blood pressure went from 125 70 to 88/37 i felt like crap i stopped the tribenzor 40-10-25mg pill and increaded the monopril to 30 mg;s my pressure has been 126/60 im feeling a feverish warm feeling i wonder if its the vitamin d 3 or coral calcium or too much b12 or could it be the withdrawals of tribenzor is a cobination drug 3 pills in one for hypertention i took alil less then half a pill of the tribenzor and the fever hot flashes went away my doctor already told me that vitamin d doesnt lower bloodpressure so what should i do and what should i say to him i have an appointment the 25th of october for a bloodpressure check up.  Please help me fit the batlle of hypertention and give me ur honesy opinion thanks doc god bless u were put on this earth to help people like me thnak you.  Just wanted to let u know im taking about 5,800 ius a day thank you.and also when i stop the monopril ive had heart fluttering ive done it before, been on it since i was 16 years old.

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