Vitamin D: powerful cancer protection

VitaminsVitamin D insufficiency is common among Americans overall but more prevalent among African Americans. A review of the literature suggests that vitamin D insufficiency is a key contributor to cancer survival disparities that exist between African Americans and white Americans (darker skin is less efficient at producing vitamin D in response to UV rays).1 A striking part of this literature review is the comprehensive summary of the existing data on vitamin D status and cancer survival: the authors present a long list of studies reporting that vitamin D adequacy is associated with reduced risk of death in all cancers combined, breast, colorectal, lung, and prostate cancer, leukemia and lymphomas.1

A protective effect of vitamin D against cancers was first proposed in 1980, based on an earlier observation that colon cancer mortality was the highest in geographical areas exposed to the least amounts of sunlight.2,3

Several more studies of geographical variations in cancers have found the same result: inverse relationships exist between sun exposure and 24 types of cancer, including the most common cancers – those of the breast, colon, rectum, and prostate.4, 5

Since 1980, evidence for the involvement of vitamin D in the relationship between sun exposure and decreased cancer risk has progressively accumulated, as associations were found between blood vitamin D levels and reduced risk of cancers.6, 7 Further support for the importance of vitamin D in cancer prevention was provided by randomized controlled trials of vitamin D supplementation that showed reduced cancer risk compared to placebo.  There have also been many reports that vitamin D receptor gene mutations, which interfere with the normal biological actions of vitamin D, were associated with increased cancer risk.8-10

Additional studies confirmed that vitamin D has growth-inhibitory effects on cells derived from breast, colon, prostate, and skin cancers.11 Vitamin D can block cancer cell growth in a number of ways: Vitamin D alters the expression of genes that regulate inflammation, cell death and cell proliferation, and also interferes with the growth-promoting actions of IGF-1 and other growth factors. Additional anti-cancer effects of vitamin D include enhanced DNA repair and immune defenses, and angiogenesis inhibition.12

Over 800 scientific papers have been published on the relationship between vitamin D and cancers. We now have ample evidence that maintaining adequate vitamin D levels is an effective strategy for protection against cancer.

Considering all of this evidence, achieving vitamin D sufficiency is so very important. Unfortunately, the Institute of Medicine is hesitant to significantly raise its vitamin D recommendations, so most multivitamins still do not contain nearly enough vitamin D (only 400 IU) to offer the security that a normal Vitamin D level will be achieved. This is an important reason why I designed my new Men’s and Women’s Daily Formula + D multivitamins to include 2000 IU of vitamin D3.  In my experience, 2000 IU has been an appropriate dose to bring most people into the favorable blood 25(OH)D range of 30-50 ng/ml (I also recommend getting a blood test to confirm adequate levels). These are the only multivitamin supplements with a 2000 IU dose of D3 plus no folic acid, beta-carotene, copper, and vitamin A. This enables most people to get everything they need without needing to take multiple different products.  For extra assurance, I’ve also utilized Vitamin D3 because of its highest biological value thus offering the most protection, which also is most effective for raising 25(OH)D levels.13 My goal is to make it as easy as possible to maintain healthy vitamin D levels, with plenty of D3 in a multivitamin which also gives you everything else that is worthy of supplementing, and carefully avoiding those supplemental ingredients that are potentially harmful; so additional supplements aren’t necessary to obtain the anti-cancer and bone-protective benefits of vitamin D and the other recommended nutrients. 



1. Grant WB, Peris AN. Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and White Americans. DermatoEndocrinology 2012;4.
2. Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer? Int J Epidemiol 1980;9:227-231.
3. Apperly FL. The Relation of Solar Radiation to Cancer Mortality in North America. Cancer Res 1941;1:191-195.
4. Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res 2006;26:2687-2699.
5. Grant WB. Ecological studies of the UVB-vitamin D-cancer hypothesis. Anticancer Res 2012;32:223-236.
6. Gandini S, Boniol M, Haukka J, et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. Int J Cancer 2011;128:1414-1424.
7. Grant WB. Relation between prediagnostic serum 25-hydroxyvitamin D level and incidence of breast, colorectal, and other cancers. J Photochem Photobiol B 2010;101:130-136.
8. Kostner K, Denzer N, Muller CS, et al. The relevance of vitamin D receptor (VDR) gene polymorphisms for cancer: a review of the literature. Anticancer Res 2009;29:3511-3536.
9. Lappe JM, Travers-Gustafson D, Davies KM, et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr 2007;85:1586-1591.
10. Bolland MJ, Grey A, Gamble GD, et al. Calcium and vitamin D supplements and health outcomes: a reanalysis of the Women's Health Initiative (WHI) limited-access data set. Am J Clin Nutr 2011;94:1144-1149.
11. Fleet JC. Molecular actions of vitamin D contributing to cancer prevention. Mol Aspects Med 2008;29:388-396.
12. Fleet JC, DeSmet M, Johnson R, et al. Vitamin D and cancer: a review of molecular mechanisms. Biochem J 2012;441:61-76.
13. Tripkovic L, Lambert H, Hart K, et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr 2012.

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Comments (10) Read through and enter the discussion with the form at the end
Gerrie Adams - July 27, 2012 12:43 PM

I understand that the appropriate amount of Vitamin D is very important to our health. However, what about the many studies that are now showing that high levels of Vitamin D intake through supplements is linked to prostate cancer in men and a host of other problems in women?

I would think that the way our bodies were intended to get Vitamin D (through the sun) would be the best way of getting enough.

Your comments to this would be valued.

Thank You.

Kevin - July 27, 2012 1:31 PM

Thank you for this information on vitamin D3; however, is there any argument to take similar amounts of D2 rather than D3? I recently heard a noted vegan diet expert expound on not using D3 because it was not made using vegan ingredients or methods.

Vivaroo - July 27, 2012 6:53 PM

I live in sub-tropical Australia, skin cancer capital of the world. Is there a safe level of sun exposure in a land where my fair skin can burn in a minute? Does the less intense early morning sun provide enough exposure for skin to produce Vit D?

annie Mcpherson - July 28, 2012 6:07 AM

Thanks for the info. You always have some good news.

Mary C. - July 28, 2012 4:34 PM

Thank you for the Vitamin D info. Question: HOW OFTEN should a senior citizen get his/her Vitamin D levels checked? What is the specific NAME OF THE BLOOD TEST one should ask for? I believe you've recommended that people keep their Vitamin D levels at the "high end" of the recommended spread. How "high" would this be for a senior citizen?

I appreciate your willingness to share clinically-valid findings to empower the patient.

Thank you for answering the above questions.

Sincerely, Mary C.

Joel Fuhrman, M.D. - July 28, 2012 5:58 PM

No study  has ever shown a negative for any cancer or any other disease for Vitamin D3 supplementation in my recommended range of intake and this recommended ideal blood level range.  Both too little and too much of any nutrient can be sub-optimal.  I carefully review every study and keep updated on all scientific data before recommendations are given.  There has  never been any evidence to show that D3 is better from the sun or that there is any downside of supplementing to this normal range.   However, there is a downside negative from trying to assure Vitamin D adequacy from the sun or tanning beds.  Wrinkling of the skin, squamous cell carcinoma, basal cell carcinoma, melanoma and solar lentigos, plus it is just impossible for most people who live and work indoors and in northern latitudes.

Lastly, D3 is the best, but if you want to assure no wool was used in fabrication, D2 is an option. 

Deana Ferreri, Ph.D. - July 28, 2012 6:09 PM

Kevin, if you are vegan and take D2 you likely need to take more, possibly double. Plus you need to make sure to take it every day to maintain levels.

Vivaroo, it is very difficult for most people to get enough sun exposure to achieve adequate vitamin D levels without damaging the skin, which is wh y Dr. Fihrman recommends supplements. You would have to get your blood levels checked to see if your sun exposure is enough for you.

Mary, ask for a 25 hydroxyvitamin D test. Levels should be between 30 and 50 ng/ml. If your levels are low, your doctor will probably recommend checking again in a few months.

Nicole Henderson - July 29, 2012 1:26 AM

Hi, Dr Fuhrman

I am concerned about the dosage. I went to a health food store some months ago and the rep sold me a bottle of D3 in 5000iu. He recommended that I take two a day and my son who is 15 takes one a day. Are you saying that these levels is to high,esp for me and my son? What dosage should be be taking? We do get some sun exposure. Of course, my son gets more than more than me because of sports. He loves to play basketball outside.

Please let me know. I am concerned about doasage since the maximum limit seems to be 5,000 for an adult.

Kathy Dyer - July 30, 2012 11:51 AM

A friend's doctor told him that as we age into our late sixties and early seventies we lose our ability to make Vitamin D from the sun? Any info on this? I am outside usually a few hours every day working in my garden, but also take 2000 IU supplement. I haven't had the blood test to determine levels as Medicare does not pay for it.

Bernard Kirzner - April 15, 2013 3:52 PM

Can UV light exposed Mushrooms provide enough Vitamin D? Are commercially available Mushrooms UV exposed?

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