Category Archives: Vitamin D

Vitamin D what is its Link to Cancer?

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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.

science_by_herryc-d4gp9xuDue 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.

Prostate 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.

Breast Cancer

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.

Colorectal Cancer

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.

stay_healthy_by_forshaka-d52ctqyCurrently it appears that keeping up your levels of Vitamin D does as well. This finding reinforces the requirement of a healthy and balanced diet for the maintenance of long term health.

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.

References

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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Vitamin D – What it does for Your Body

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By: Andrew Stewart                                                                                              Published 07/26/13

Hopefully after reading my last post you have some background on Vitamin D (If you’re still confused check out the links I included at the bottom of that post).

I think the next logical area I will cover is what researchers generally accept that Vitamin D does for you.

Like I mentioned earlier, Vitamin D does a ton of work within our bodies so this post is just going to scratch the surface.

Vitamin D, Calcium, and Phosphorus

femur_by_monorok-d5f7npeUnder “normal operating conditions” Vitamin D increases the efficiency of the small intestine. Contrary to popular belief, the intestines actually are extremely important for getting the nutrients out of our food – more so than the stomach. Anyway, Vitamin D allows us to get more Calcium and Phosphorus from the food we eat and into our bloodstream (DeLuca 1988). Both Calcium and Phosphorus are essential in our bodies for a multitude of biological processes which contribute to its normal growth, development, and maintenance.

Increasing levels of Phosphorus and Calcium in our blood helps the body build and maintain stronger bones. If you are at risk for osteoporosis or perhaps have recently broken a bone getting adequate levels of Vitamin D in your diet can help you increase bone mass/healing. The majority of the research published in this area is in agreement – low levels of Vitamin D have been observed to result in a slightly increased risk of bone fracture (Scragg 2011).

Vitamin D and Muscles?

While most people associate Vitamin D with bone, did you know that it also acts on your muscles? Without going too in depth into skeletal muscle physiology Vitamin D helps move Calcium into muscle cells.

Once Calcium gets moved to the right area in your muscle cells it interacts with the small contractile proteins which work together to develop force in your muscles (via a process called the Cross-Bridge Cycle). Lower levels of Calcium in muscles reduce your ability to contract them which contributes to the feeling of fatigue (2002 Pfeifer et al.). While muscle weakness after a workout doesn’t necessarily mean that your Vitamin D is low, it may contribute in part to that long term fatigue experienced during those dark winter months.

Vitamin D Enemy of Bacteria

The final aspect of Vitamin D I will look at today is that of an Immune Booster within our bodies. The role of Vitamin D in the immune system was first considered after the discovery of Vitamin D receptors in many different types of immune cells within the human body. It now appears tMacrophage_by_dclaudiobhat Vitamin D induces anti-mycobacterial activity in certain immune cells that make up the first line of defense in our bodies against foreign invaders.

Currently, it looks like Vitamin D modifies gene regulation causing a plethora of changes in these cells. The result is the production of strong bacteria eating macrophages (bacterial eating/killing cells) that are better at their job. Vitamin D allows the body to create cells that are both more effective at killing bacteria and are able to kill more bacteria before they run out of juice (2010 Baeke). When it comes to your immune system you definitely want it in tip top shape!

Now, in the media there has been quite a lot of buzz regarding Vitamin D and Cancer – I am saving this for last and will dedicate a whole post to the issue. You can look forward to this post within the next day or two. In the meantime, you can check out some of the literature I have cited below to get an in-depth view of the way Vitamin D works in our bodies.

References

Baeke, F., Takiishi, T., Korf, H., Gysemans, C., & Mathieu, C. (2010). Vitamin D: modulator of the immune system. Current Opinion in Pharmacology, 10(4), 482-496. doi: http://dx.doi.org/10.1016/j.coph.2010.04.001

DeLuca, H. F. (1988). The vitamin D story: a collaborative effort of basic science and clinical medicine. The FASEB Journal, 2(3), 224-236.

Pfeifer, M., Begerow, B., & Minne, H. W. (2002). Vitamin D and Muscle Function. Osteoporosis International, 13(3), 187-194. doi: 10.1007/s001980200012

Scragg, R. (2011). Vitamin D and public health: an overview of recent research on common diseases and mortality in adulthood. Public health nutrition, 14(9), 1515-1532.

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The basics of Vitamin D – what is it and what does your body do with it?

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By: Andrew Stewart                                                                                                      Published 07/23/13

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Let’s start off first by recognizing that “Vitamin D” isn’t necessarily one unique substance that our bodies need. It’s really an umbrella term which describes a group of molecules of similar structure.

For example, Vitamin D3 (Cholecalciferol) is created in our skin when it is exposed to energy from the sun. In a sense, Vitamin D3 isn’t a true vitamin. With adequate exposure to the sun (UVB) we can get along just fine without supplementation.

There are also forms of Vitamin D in the foods we eat. This form is commonly called Vitamin D2 or “Ergosterol” and can be found in eggs, fish oils, and many plants but generally in low levels. Many food suppliers now add Vitamin D to foods to increase the levels of Vitamin D in our diet.

Now, Vitamins D2 and D3 on their own don’t do much for our bodies – they are raw substances that require some processing before we can put them to use. Through the use of our liver and subsequently the kidneys a series of structural conversions occur creating a compound with the fancy name of 1,24-dihydroxycholecalciferol. Just like its precursors it is what we call a fat soluble compound.

As I am sure you know, we are mostly water and fats don’t dissolve too well in water. To account for this we have special Vitamin D binding proteins which protect the activated Vitamin D and shuttle it throughout our bodies to where we need it most.

Ok, now that our bodies have processed the Vitamin D we need and it is floating around in our bloodstream how do our cells get at it? Well, the Vitamin D carrier proteins pull the Vitamin D through the protective membrane (outer wall) in our cells so that it is exposed to the inner cellular machinery responsible for everyday function. In order for Vitamin D to work though, it needs a way of communicating with our machinery.

Lego_Thumbdrive_by_m_schneiderDeep inside our cells are Vitamin D Receptors. To simplify things, you can think of these receptors as a Lego with two open spots. One clips on to the bioactive Vitamin D, and the other onto our DNA. Once the receptor is clipped onto both, the way our DNA is read changes, and as a result different machines (systems) are turned on or shut down. This leads to a myriad of changes within our bodies. In fact, so many changes occur due to Vitamin D that researchers still don’t know everything that it does!

Ok, to prevent too much information overload I’m going to end here for today. In my next post I will start to go through what researchers think Vitamin D changes in the body. Later this week I will attempt to cover some of the Vitamin D controversy currently being brought up in the news; specifically, can Vitamin D do everything people say it does?

References

Bowen, R. A. (2011) Vitamin D (Calcitriol). Pathophysiology of the Endocrine System. Retrieved June 23, 2013, from http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/otherendo/vitamind.html

Higdon, J. & Drake V. (2011) Vitamin D. Oregon State University Micronutrient Information Center. Retrieved June 23, 2013, from http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/index.html

Mayo Clinic (2012) Vitamin D and Related Compounds (Oral Route, Parenteral Route). Mayo Clinic Drug Information. Retrieved June 23, 2013, from http://www.mayoclinic.com/health/drug-information/DR602171

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