Top 3 Things To Know about Vitamin D and Cancer
Over the years, controversial evidence from several studies have either supported or invalidated the idea that vitamin D deficiency increases the risk of cancer development. This article aims to review the anti-cancer potential of vitamin D and our current knowledge relating to vitamin D and cancer. Here are the top 3 things you absolutely need to know:
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| Fortified milk, a decent source of vitamin D |
1. Your Vitamin D Status Depends on Various Factors
Vitamin D is not really an essential element to be obtained from the diet since adequate amounts can be obtained via ultraviolet rays of the sun. However, several lifestyle factors, genetic, and environmental factors may lead to inadequate vitamin D status. Lifestyle factors may include indoor occupation or traditional attires that involve covering the skin completely. Genetic factors include dark skin pigmentation that reduces the effectiveness of vitamin D synthesis from the sun. Environmental factors include low levels of sunlight or winter seasons with little to no sunlight. These factors reduce the human body's potential to harness vitamin D from the sun, thus making this vitamin conditionally essential from the diet or supplements. For sun exposure times, natural food sources, and requirements see here.
2. How Vitamin may Fight Against Cancer
In the body, vitamin D is quickly converted to the potent steroid hormone, calcitriol. Calcitriol is required for the activation and function of Vitamin D Receptor (VDR) which is present inside almost all cells in the body. Upon activation of VDR by calcitriol (obtained from Vitamin D), VDR in conjunction with other proteins could bind to the DNA in order to drive several anti-tumor functions. In simple terms, these functions include:
- Decrease cancer cell growth (proliferation)
- Drive cancer cell death (apoptosis) by suppressing factors that enable cancer cells to escape the natural cell death program that is intrinsic to normal cells.
- Reduce cell signaling that leads to inflammation
- Prevent the breaking away of cancer cells from the original tumor site (metastasis and invasion)
- Decrease the development of new blood vessels in the tumor environment (angiogenesis). Over time, this reduces the supply of blood to the tumor microenvironment thereby starving cancer cells of vital nutrients necessary for their survival.
3. Vitamin D may prevent Cancer-related Deaths
Due to the anti-cancer potential of vitamin D, several studies have aimed to link this vitamin to cancer development and prevention. Indeed, pre-clinical trials showed significant promise but the evidence in humans have been controversial at best. However, a recent meta-analysis of ten randomized clinical trials concluded that while vitamin D supplementation does not impact the incidence of cancer development, but it significantly reduced total cancer mortality by 13%. However, the authors from Havard T.H. Chan School of Public Health noted that it is unknown if this effect is equal across all ethnicity since most studies included in their analysis had Caucasians as the major study participants. The ethnicity of study participants becomes important since an older study associated vitamin D deficiency with cancer incidence and mortality in African-Americans. Also, it is unclear if the anti-tumor action of vitamin D is site-specific, although some evidence suggests that it may be more effective on tumors along the digestive tract.
Put together, this information suggests that paying more attention to vitamin D status may be vital to the management of certain types of cancer and optimum health of the human body.
Useful Resources
- Feldman D et al. 2014. The role of vitamin D in reducing cancer risk and progression: https://www.nature.com/articles/nrc3691
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