Vitamin D may protect against colon cancer

Vitamin D insufficiency is widespread, and is thought to contribute to a variety of disease states, including osteoporosis, cardiovascular disease, diabetes, autoimmune diseases, depression, and cancers.

Vitamin D affects calcium absorption and metabolism in the bone, kidney, and intestine, but it also acts as a regulator of gene transcription in many tissues, affecting genes that control cell growth, adhesion, differentiation, proliferation, and programmed cell death. Vitamin D’s action on such genes has been shown to suppress proliferation of human colon cancer cells and tumor growth.1,2

Also, the cells of the colon, whether they are normal or cancerous, are capable of converting 25(OH)D to its active form 1,25(OH)2D. It is likely that this ability has purpose – vitamin D may have yet unidentified actions specific to the cells of the colon.

Researchers analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which has over 520,000 participants. Blood levels of vitamin D, which were measured at the start of the study, were compared between 1248 colorectal cancer patients and matched controls after diagnosis.

Circulating 25(OH)D levels of below 20 ng/ml were associated with increased risk of colorectal cancer compared with levels between 20-30 ng/ml.  When the researchers arranged the data into 5 quintiles of Vitamin D levels, they found a dose-dependent reduction in colon cancer risk; highest quintile (greater than 40 ng/ml) had 40% reduced risk compared to lowest quintile (less than 10 ng/ml). When cancers were distinguished by site, the association between Vitamin D levels and colon cancer was even stronger – the highest quintile showed a 60% risk reduction.3

This large study followed up at least 25 previous studies since 2002. A 2009 review of these previous studies confirmed that there is indeed an inverse relationship between vitamin D levels and colorectal cancer. Even after a diagnosis of colon cancer, vitamin D levels are associated with increased survival – in colon cancer patients, higher vitamin D levels were predictive of a decreased risk of death from any cause, not only colon cancer.4

The 2009 review concluded that 25(OH)D levels of 32 ng/ml would be sufficient to achieve the protection against colorectal cancers seen in the literature, and the most recent study cited saw benefits with as low as 20 ng/ml. A minimum of 30 ng/ml 25(OH)D is thought to be required for vitamin D to properly exert its many beneficial effects.5 Accordingly, I  recommend that levels be maintained in the range of 35-55 ng/ml. 

About 50% of the U.S. population is deficient in vitamin D and cannot rely on sun exposure because of indoor jobs, skin color, and their climate. Plus, with the depletion of the ozone layer, the amount of sun most people would require to achieve these levels may result in too much skin damage and skin cancer.6 



1. Ingraham BA, Bragdon B, Nohe A. Molecular basis of the potential of vitamin D to prevent cancer. Curr Med Res Opin. 2008 Jan;24(1):139-49.

2. Journal of Clinical Investigation (2009, July 7). Understanding The Anticancer Effects Of Vitamin D3. ScienceDaily. Retrieved April 6, 2010, from /releases/2009/07/090706171500.htm

Emory University (2008, April 14). Vitamin D And Calcium Influence Cell Death In The Colon, Researchers Find. ScienceDaily. Retrieved April 6, 2010, from /releases/2008/04/080413161052.htm

Rockefeller University Press (2008, November 26). Vitamin D Can Alter Color Cancer Cells In Many Ways, Through One Pathway. ScienceDaily. Retrieved April 6, 2010, from /releases/2008/11/081117091614.htm

3. Jenab M, Bueno-de-Mesquita HB, Ferrari P, et al. Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations:a nested case-control study. BMJ. 2010 Jan 21;340:b5500.

High vitamin D levels linked to lower risk of colon cancer. ScienceDaily. Retrieved April 6, 2010, from /releases/2010/01/100122002340.htm

4. Dana-Farber Cancer Institute (2008, June 20). Vitamin D Linked To Colon Cancer Survival. ScienceDaily. Retrieved April 6, 2010, from /releases/2008/06/080619090749.htm

5. Holick MF, Chen TC. Vitamin D deficiency: a worldwide problem with health consequences.Am J Clin Nutr 2008;87(suppl):1080S– 6S.

6. Terushkin V, Bender A, Psaty EL, et al. Estimated equivalency of vitamin D production from natural sun exposure versus oral vitamin D supplementation across seasons at two US latitudes. J Am Acad Dermatol. 2010 Apr 2. [Epub ahead of print]


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Comments (4) Read through and enter the discussion with the form at the end
Stephanie - April 14, 2010 12:37 PM

Assuming one were to get the appropriate amount of Vitamin D from the sun, how long would one need to stay outside (with sunblock on)? I have your vitamin D supplement, but I haven't been taking it lately because I'm spending a lot of time outside now that the weather's nice. Should I still take it anyway?

Diane - April 14, 2010 3:03 PM

You "recommend that levels be maintained in the range of 35-55 ng/ml." I currently take 1,200 IU daily of Vitamin D3. How much is 35-55 ng/ml in comparison? Thanks

Dr. Fuhrman - April 15, 2010 9:01 AM

I am not sure exactly because I do not know enough about you. The amount of sunshine needed to obtain adequate Vitamin D is very variable based on skin color, genetics, latitude, time of day, sunscreen use, how much skin is exposed, and how soon the skin is washed after exposure. Studies indicate that the variance is so wide, that for most Americans that work indoors during the day, sunshine cannot be depended on to repair the epidemic of deficiencies in America. However, whether you are using sunshine or supplements or some combination, the most important thing is to confirm adequacy with a blood test, because the risk of deficiency is too large to ignore.

To achieve the 35 – 55 ng/ml range (used in the US) most people need to take between 1500 – 2500 IU of Vitamin D. So you might need a little more if you are not getting any sun.

Paul - April 22, 2010 4:16 PM

I received this article from my "Living the CR Way" contacts. Remember though, the dose makes the poison. And Vitamin D is a fat soluble vitamin, meaning more persistent than a water soluble vitamin. It's a mouse experiment written in typical gobbledygook. But figured what it said in plain english is that some genetically modified mice got a tad too much vitamin D and exhibted an appearance (why just say appearance instead of phenotype??) of premature aging. Tons of caveats I'm sure such as it's a mouse study not a human one, etc... Fair enough. Point is that it's a fat soluble vitamin that we are usually on the low end of. Don't over do it though. We're not sure of what the risks are on the other side.


Is Vitamin D making you age faster?

Thinking about how much vitamin D to take? This provocative study from Harvard dental school showed that Vitamin D under certain circumstances might cause accelerated aging:

Trends in Molecular Medicine. 2006 Jul;12(7):298-305.
Hypervitaminosis D and premature aging: lessons learned from Fgf23 and Klotho mutant mice.
Razzaque MS, Lanske B.

Department of Developmental Biology, Harvard School of Dental Medicine,

The essential role of low levels of vitamin D during aging is well documented. However, possible effects of high levels of vitamin D on the aging process are not yet clear. Recent in vivo genetic-manipulation studies have shown increased serum level of vitamin D and altered mineral-ion homeostasis in mice that lack either fibroblast growth factor 23 (Fgf23) or klotho (Kl) genes. These mice develop identical phenotypes consistent with premature aging. Elimination or reduction of vitamin-D activity from Fgf23 and Kl mutant mice, either by dietary restriction or genetic manipulation could rescue premature aging-like features and ectopic calcifications, resulting in prolonged survival of both mutants. Such in vivo experimental studies indicated that excessive vitamin-D activity and altered mineral-ion homeostasis could accelerate the aging process.

PMID: 16731043

However, studies looking at vitamin D and prostate or breast cancer incidence have shown the vitamin to have a protective effect.

When evaluating studies like these, we look at the actions of vitamin D at the molecular level and compare them to calorie restriction, the gold standard for slowing aging and protecting against cancer.

We will be discussing this study at the upcoming New York Chapter of the CR Society Intl.. The meeting is free and open to everyone:

This Sunday at 4 PM

LifeThyme Natural Market

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