By: Andrew Stewart Published 07/29/13
There has been a lot of buzz in the news recently talking about Vitamin D and Cancer prevention. With the exception of daily recommended allowances, this is the most controversial area relating to Vitamin D.
Vitamin D Researchers and the Media
When health research is passed on to the general public it is often reduced down – it is a challenge for anyone to reduce 10 years of work into a succinct newspaper article or 2 minute news clip. This coupled with the “publish or perish” mentality in academia results in the production of news that while not necessarily untrue is greatly exaggerated. To help clarify, I’ll start by giving a brief summary on the general progression researchers take from theory to scientific fact.
Due to the nature of medical research and the progress we have made regarding ethics researchers generally have to start on a small scale and work their way up the scientific totem-pole. Long gone are the days of the Dr. Frankensteins who perform questionable experiments in their attic. When medical research pertaining to humans is done in a new area it is the researcher’s responsibility to prove (within reason) that what they are attempting to do won’t have unforeseen effects that endanger the people they are trying to help.
As a result, much work is done on clumps of cells from various donor species or on animal models that we recognize (through additional research) to be similar in some particular way to the human body. The work done in this area is termed “pre-clinical”. It is often a much easier, cheaper, and safer to study something. This however often comes at the cost of application – not everything that is true on a small scale is true in the real world.
The jump from pre-clinical testing to clinical testing in humans can be a rather large one. There is no guarantee that what worked before will work in humans. The human body is amazingly complex with many variables that can get in the way.
In the case of Vitamin D it appears that promising results in the lab do not always result in medical breakthroughs in humans. In 2011 a researcher by the name of Simone Mocellin collected a large body of scientific literature and dissected it to see if different researchers around the world were in agreement regarding the effects of Vitamin D on Cancer. The conclusion that was drawn was that “overall a relationship between vitamin D and cancer does exist, although its strength appears to weaken as we move from the preclinical to the clinical ground” (Mocellin 2011).
Below I have broken down what I have found researchers are generally saying about Vitamin D and different types of Cancer.
Upon writing this article, it would appear that the majority of the work done regarding the relationship between the circulating levels of Vitamin D in your blood and the risk of developing prostate cancer has lead to the conclusion that low levels of Vitamin D either do not lead to an increased risk of developing prostate cancer (2011 Mocellin, 2009 Yin et al, 2010 Gandini et al.). I found this agreement across three different meta-analyses which lend a significant amount of support to this conclusion.
Similar to the case of Prostate Cancer, low circulation levels of Vitamin D in the blood currently do not appear to increase the risk of developing Breast Cancer (Gandini 2011, Chen 2010). Within the literature studied by Mocellin, there was one exception which indicated that increased risk of Breast cancer occurred with lower levels of Vitamin D. I tried to find a copy of this paper (Yin 2010) to take a look at it to see what they said but was unsuccessful – it does appear that their opinion is in the minority.
Now so far it appears that researchers haven’t come up with much regarding Vitamin D and Cancer, I did however save the best for last. When researchers have studied Colorectal cancer they found that increased levels of Vitamin D does result in a reduction in Cancer risk! (Gorham 2007, Yin 2009, Gandini 2010)
It is commonly accepted that diet and nutrition plays a large role in protecting ourselves from the risk of developing Colorectal cancer.
Well, I believe that this concludes our month on Vitamin D. I hope these posts have contributed to your knowledge on the subject and hopefully addressed some of the controversy that exists on the topic. If you are looking for more in depth information on the topic feel free to peruse the works cited, the researcher papers I have referenced all come from reputable journals with rigorous peer-review processes.
Mocellin, S. (2011). Vitamin D and cancer: Deciphering the truth. Biochimica et Biophysica Acta (BBA) – Reviews on Cancer, 1816(2), 172-178. doi: http://dx.doi.org/10.1016/j.bbcan.2011.07.001
Yin, L., Raum, E., Haug, U., Arndt, V., & Brenner, H. (2009). Meta-analysis of longitudinal studies: Serum vitamin D and prostate cancer risk. Cancer Epidemiology, 33(6), 435-445. doi: http://dx.doi.org/10.1016/j.canep.2009.10.014
Gandini, S., Boniol, M., Haukka, J., Byrnes, G., Cox, B., Sneyd, M. J., . . . Autier, P. (2011). Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. International Journal of Cancer, 128(6), 1414-1424. doi: 10.1002/ijc.25439
Chen, P., Hu, P., Xie, D., Qin, Y., Wang, F., & Wang, H. (2010). Meta-analysis of vitamin D, calcium and the prevention of breast cancer. Breast Cancer Research and Treatment, 121(2), 469-477. doi: 10.2105/AJPH.2004.045260
Gorham, E. D., Garland, C. F., Garland, F. C., Grant, W. B., Mohr, S. B., Lipkin, M., . . . Holick, M. F. (2007). Optimal Vitamin D Status for Colorectal Cancer Prevention: A Quantitative Meta Analysis. American Journal of Preventive Medicine, 32(3), 210-216. doi: http://dx.doi.org/10.1016/j.amepre.2006.11.004
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