Vitamin D – Two new studies

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Here is a sad confession: I often think about topics on which I blog when a news article appears or, even more often, when one of the many medical websites that fill my email box each day with targeted posts (and ads) sends something new. For a really hilarious read on the email scene, if you are a subscriber to the New Yorker, click here for an outstanding Shouts and Murmers article regarding “walk-in bathtubs” by Calvin Trillin. But I digress…

With thanks to the good folks at Medscape, two articles worth knowing about suggest that in spite of my general anti-supplement stance, you really SHOULD consider vitamin D supplementation, or at the least know your levels and think about it. Vitamin D (cholecalciferol, D3) is actually a member of the steroid superfamily. (called secosteroids) Thus, there can be interactions between various forms of Vitamin D and other steroid receptors in all likelihood if certain mutations occur. This could be good or bad, but provides a plausible explanation for why Vitamin D (and other non-androgen types of molecules) might play a role in prostate cancer.

In one article, Chinese investigators did a review of 25 studies that evaluated the Vitamin D levels in over 17,000 patients with various cancers and found that those patients with the highest levels lived significantly longer than those with the lowest levels.  A similar study appeared in the British Medical Journal last month, evaluating >800,000 patients from 73 studies and reached a similar conclusion: “Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease, cancer, and other causes. Supplementation with vitamin D3 significantly reduces overall mortality among older adults; however, before any widespread supplementation, further investigations will be required to establish the optimal dose and duration and whether vitamin D3 and D2 have different effects on mortality risk.”

In the other article highlighted by Medscape, baseline 25-OH Vitamin D levels were evaluated in men undergoing prostate biopsies. Among both African American and European American men, severe deficiency (<12 ng/ml) was associated with higher Gleason scores and more advanced stage disease. In the AA population, <20 ng/ml had a significant association with a positive biopsy.

The problem, of course, is that when experts review these and similar articles, they really cannot come to a strong consensus on what to do for the general population, let alone for the cancer population. In this review, the authors point out all of the pitfalls in taking publications like the two Medscape articles as “gospel”. Quoting their abstract, “vitamin D use and cancer may not have correctly addressed the question, and that new randomized trials should be organized. The reasons are due to several unsolved issues including selection of the effective dose, varying baseline levels of subjects before randomization, compliance with the intervention, contamination of the placebo group (i.e., intake of vitamin D supplements by subjects allocated to the placebo group) and unknown effective lag time between start of the intervention and disease onset.”

“So what would you do, doctor?” Ah, the piercing question… What I did was measure my 25-OH Vitamin D level and found that it was very low. I’m now taking 2-4000 U/day of D3, and I plan to remeasure my level in a couple of months. So there! (BUT – I’m still slathering on the sunscreen that probably got me deficient in the first place)


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11 responses to “Vitamin D – Two new studies

  1. These vitamin D studies, as impressively large as they are to date, only prove strong association between low vitamin D levels and disease. The research has not crossed the threshold of prospective trials that tell us whether this association is causative or reactive. That is did the low vitamin D lead to or cause the long list of diseases that we link to vitamin D, or is there something about all of these diseases that triggers lower vitamin D in the body? People with pneumonia, bronchitis, arthritis and cancer will generally have low serum iron but this does not mean iron deficiency causes these diseases; rather these diseases trigger a reaction that shifts iron out of the blood into its storage form.

    Yet as there is little risk from taking moderate supplemental doses of vitamin D, and the majority of men your age in Denver test low, it makes sense to take it. Low risk, potentially big pay off. Why not?

  2. Dave Stevens

    Dr. Glode – – is regular Vitamin D monitoring a part of your standard of care for prostate cancer patients? (I am taking two, 1,000U tablets per day of D3. Perhaps I should up it to four per day to get me to the 4,000units?

    • Although I haven’t routinely monitored 25-OH Vitamin D levels, I think we should, particularly perhaps in cancer patients, but probably in everyone. We certainly monitor cholesterol, for example, on a fairly routine basis, although the link to cardiac disease for hypercholesterolemia is probably much stronger than the link between low levels of D and various diseases. In any case, I am doing it more often in my patients, especially those on ADT who are at higher risk for bone loss, and knowing your level before you “up it” is probably wise. Once the serum levels are in the normal range, (30-74ng/ml) taking enough to keep them there makes sense. In one of rhe responses below, a respondent concluded I am taking 8000U/d based on my post which I should have been more clear about. I am taking 2000-4000 units/day at present and plan to do this for about 3 months then remeasure my levels. I also agree with drjacobschor that one could take higher levels until you get into the normal range.

      • Dave Stevens

        Sounds good. My PSA will probably pop up over 1.0 by June triggering a visit with you on next steps. We could include a Vitamin D analysis at that time. (PSA seems to be rising at an average of 0.10 per month as of last blood draw.)

  3. Marshall Freedman

    I can’t remember much about vit D poisoning.

    • Dave Stevens

      Here is what Mayo Clinic says about Vitamin D poisoning: “Taking 50,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity.” Full article is at:

      So, if we take Dr. Glode’s regimen at 8,000 units per day there should be no problems.

      • drjacobschor

        In the paper cited by the Mayo Clinic referenced above, [], we should note that of the patients they had identified with hypercalcemia associated with taking these massive amounts of vitamin D, the authors point out, “….most had a disorder that can be associated with hypercalcemia….”

        Even these large doses of vitamin D appear to be a problem when coupled with some other underlying disorder that increases risk for hypercalcemia, in the case of the 9 patients reported in this paper, these conditions were “… squamous cell cancer (n = 1), Pneumocystis or mycobacterial infection (n = 3), lymphoma (n = 1), granulomatous disease (n = 1), hyperthyroidism (n = 2)”.
        Testing serum 25(OH)D-3 levels first, and supplementing if need be with 5-10,000 IUs of D-3 per day until levels are back in the normal range is unlikely to cause a problem. Monitoring serum calcium if there is any concern is a simple enough precaution to take.
        While there is still not conclusive evidence that vitamin D will help all the conditions it is promoted for, there is very low risk for harm.

  4. Don Morris

    Shouldn’t your 1,25(OH)2D , the active form of Vit-D, also be checked occasionally to make sure your kidneys are converting the 25OHD (normally measured in a blood test) in sufficient quantity to the active form?

  5. Bob Lederer

    Another great contribution on a relatively common issue that many of us take for granted. I had to request and remind my provider that measuring my Vitamin D level was important. You remind us that if we adhere to the recommendation to use sunblock we interfere with natural vitamin D. In addition, a large number of us have become lactose intolerant with age and drink very little milk.

  6. drjacobschor

    The active form of vitamin D, 1,25(OH)D is rarely checked as the results are difficult to interpret. Serum levels fluctuate greatly and do not reflect nutritional status. Few of the studies report levels either. It seems odd but that’s how it is.

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