VDC test kit slider
VDC test kit slider
sperti logo 1
Text size A A A
High contrast on off

Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Vitamin D: Breast cancer treatment effect?

In a remarkable paper from Stanford University, Dr Swami and company, working under senior author Professor David Feldman, discovered that vitamin D has a treatment effect in mice that have surgically implanted inflammatory breast tumors. This is the same famous Dr Feldman who edits the textbook, Vitamin D.

Swami S, Krishnan AV, Wang JY, Jensen K, Horst R, Albertelli MA, Feldman D. Dietary vitamin D₃ and 1,25-dihydroxyvitamin D₃ (calcitriol) exhibit equivalent anticancer activity in mouse xenograft models of breast and prostate cancer. Endocrinology. 2012 Jun;153(6):2576-87.

The authors discovered that the effect of higher doses of vitamin D were equal to the anticancer effects of activated vitamin D (calcitriol) in these mice. Calcitriol’s anti-cancer effect in mice has been known for many years. In humans, resulting high blood calcium has limited the usefulness of calcitriol or similar analogues in treating cancer.

The researchers divided the mice into many groups, to either induce cancer into some of them, use some of the mice as healthy controls and to administer different amounts of vitamin D or calcitriol. For vitamin D groups, they administered it through their diet (chow). For calcitriol, they administered it through injections. Again, while there were many groups, here are the four most important groups to compare:

  • One group with breast cancer received 5,000 IU of vitamin D per kg of chow
  • One group with breast cancer received 1,000 IU of vitamin D per kg of chow. This was the first control group.
  • One group with breast cancer received calcitriol at injections of .05 µg/week. They also received 1,000 IU of vitamin D per kg of chow.
  • One group without breast cancer received 5,000 IU of vitamin D per kg of chow. This was a second control group.

Amazingly, the mice receiving 5,000 IU of vitamin D/kg of chow showed greater than 50% tumor shrinkage in four weeks compared to the 1,000 IU/kg of chow group. Unfortunately, the actual dose of vitamin D in an IU/kg/day format was not available. It takes mice months to consume a kg of chow.

In the mice with cancer on the 5,000 IU of vitamin D/kg of chow, 25(OH)D was only 38 ng/ml, but calcitriol was elevated in these mice at 117 pg/ml. Interestingly, when the researchers gave mice without cancer 5,000 IU of vitamin D/kg of chow, their levels of calcitriol did not spike nearly as high and were only at 72 pg/ml, possibly suggesting that the breast tumor was making the extra calcitriol.

However, there was evidence of another mechanism. In the cancerous mice taking 5,000 IU/kg of chow, the enzyme that makes calcitriol was elevated in the intestine (intestinal wall specifically), as well as in and around the tumor. No such elevation was seen in the non-cancerous control mice taking the same amount, suggesting the tumor, or the immune system’s response to the tumor, was somehow increasing systemic calcitriol increases.

We do know that in the test tube, calcitriol inhibits inflammatory breast cancer cells but has little effect on non-inflammatory breast cancer cells.

Hillyer RL, Sirinvasin P, Joglekar M, Sikes RA, van Golen KL, Nohe A. Differential effects of vitamin D treatment on inflammatory and non-inflammatory breast cancer cell lines. Clin Exp Metastasis. 2012 May 20. [Epub ahead of print]

In the Swami et al study, 5,000 IU/kg of chow also suppressed estrogen levels by 75% and aromatase (an enzyme that makes estrogen) by a similar amount in cancerous postmenopausal mice. In postmenopausal breast cancer, estrogen in tumor and surrounding fat tissue is thought to drive the tumor’s progression, raising the possibility that vitamin D will decrease aromatase activity and estrogen levels in human females with breast cancer.

However, the vitamin D physiology and pharmacology of mice and humans are quite different, so we have no idea of what dose might be effective in having a treatment effect in women with breast cancer. It does appear the dose must be high enough to raise calcitriol levels in breast cancer patients, as the authors found evidence that the elevated calcitriol levels were contributing to vitamin D’s anti-cancer effects.

In normal humans, the dose of D3 needed to raise calcitriol levels appears to be in the highly toxic range. In the study of 11 vitamin D toxic patients below, all with very high blood calcium, only three had elevated levels of calcitriol. If researchers have measured calcitriol levels in women with inflammatory breast cancer on adequate doses of vitamin D, I am not aware of that study.

Pettifor JM, Bikle DD, Cavaleros M, Zachen D, Kamdar MC, Ross FP. Serum levels of free 1,25-dihydroxyvitamin D in vitamin D toxicity. Ann Intern Med. 1995 Apr 1;122(7):511-3.

Remember, the dose used in this study was not 5,000 IU/kg of body weight, rather 5,000 IU per kg of chow; please keep that in mind. 5,000 IU/kg of body weight would be 250,000 IU per day for a 110-pound woman. Such doses would always lead to toxicity and probably death if taken for several months.

Swami et al’s study is so interesting that I hardly know what to say, other than quote the authors, who concluded:

“At the supplement levels that we tested, our data support the hypothesis that dietary vitamin D3 is useful in the chemoprevention and treatment of breast cancer since it is an economical and easily available nutritional agent that is as active as calcitriol in inhibiting tumor growth with minimal hypercalcemic side effects. However, the use of very high doses of dietary vitamin D3 in the presence of cancers will require careful monitoring for hypercalcemia.”

However, given the fact that even toxic doses of vitamin D do not consistently raise calcitriol  levels in normal humans, we do not know how much of this animal study can be transferred to women with breast cancer. We continue to recommend that anyone with cancer keep their 25(OH)D in the high range of normal, not in toxic ranges.

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

6 Responses to Vitamin D: Breast cancer treatment effect?

  1. Lots of vitamin D works well for cancers, etc.– provided cofactors are adjusted

    There have been several clinical trials reports of problems using vitamin D as a monotherapy. Vitamin D increases the bio-availability of Calcium. Most people now lack the Vitamin K2 needed to put the excess Calcium created by the vitamin D into bones. Instead, the excess Calcium is deposited elsewhere in the body, in places such as arterial walls and breasts. People taking more than about 3,000 IU of vitamin D daily should really try to balance their cofactors.

    Brief cofactor summary:

    – reduce Calcium < 500 mg daily,

    – increase Magnesium to 500 mg daily,

    – take Vitamin K2 – 100 mg daily.

    Details about cofactors: http://is.gd/cofactors

    It describes several more and provides many low cost options for getting the cofactors

    The Vitamin D Council described cofactors in 2011


    101 vitamin D intervention trials added in just the first 7 months of 2012.

    I am unaware of any ongoing trial which balances more than one cofactor.

    Almost all use monotherapy (half of the subjects take vitamin D and see what happens)

    List of the 101 new vitamin D intervention trials: http://is.gd/intervention

    Which includes 8 reasons why many of the trials will not be successful.

  2. Ian says:

    How does vitamin K2 affect these results. Would a human be able to tolerate a higher dose of vitamin D if the vitamin K levels were also increased. I note the IOM has not set an UL for the menaquinones. So it may be possible to take as much as 25mg/Kg.

  3. Failed to mention in previous comment

    There are many ways to optimize vitamin D response to a dose

    Some of the optimization methods MAY not increase Calcium problems

    Increase Vitamin K2

    Take your vitamin D with the largest meal of the day:

    Increase the monosaturated fats in your diet (e.g. almonds)

    Increase Magnesium

    Increase Boron

    Increase Cholesterol in your diet – for absorption through your gut

    Increase Omega-3 which may increase by 60% the ACTIVE form, not the tested form

    Avoid having too much vitamin A

    Those people with poor guts should use a more bio-available form

    Details at: http://is.gd/2xvitd

    By the way: most of the cofactors are available combined in low cost liquid or pill form

    Details: http://is.gd/cofactors

  4. Umileritac@aol.com says:

    hlahore@gmail.com–thanks for your last post on co-factors. Such good information. Perhaps if following this protocol, it isn’t even necessary (or beneficial) to consume a calcium supplement? It is easy to get under 500 mg calcium daily from food selections.

    Again, really appreciate your post.

    Rita Umile

  5. rcessna says:

    Dr. Cannell,

    Went to the Dr. today. Chest X-Ray, blood work.

    Asked him to check my Vitamin D3 level.

    Last time, 10 months or so, my level was 100 ng/ml.

    He asked if I knew that there was an increased risk for CHD with anything

    over 50. My research has not shown this to be true.

    What’s your take on this.


    Ray Cessna

  6. @Rcessna: ANYTIME a practitioner provides you with a statement as fact, like “there was an increased risk for CHD with anything over 50”, it is perfectly reasonable to ask for the reference so that you can study up on it – ask in a respectful and polite but firm way, of course, you are in a professional relationship and you after all, want to know as much as you can about your condition,right? :) And when he gives you that study, put it up here where Dr. J can review it…..

    My other curiosity is with his value of “50”, wherein I would confirm he is working from a lab test 25(OH)D results, AND that he is aware that women lactating postpartum will not pass vitamin D to the infant when the level is NOT in the 40 to 50 range, for example..and that mother nature puts many indigenous groups, as well as laborers, life guards, well into their 50 ng/ml ranges and what does he think about the lack of CHD epidemics in these groups.. Doctors are incredibly stressed for time, and may sometimes see a synopsis written by a drug company hostile, or take away the wrong conclusion from a non-medical journal “news” article. Many times an editor for a tabloid or magazine will distort the content with a completely inane headline that is the only thing many people will read. Regardless, work with your doctor to educate both him and yourself, and perhaps you can benefit more than just you two. (if it improves his standard of practice with other patients….)