What You Need to Know: Cancer patients who have higher levels of vitamin D when they are diagnosed tend to have better survival rates and remain in remission longer than patients who are vitamin D-deficient.
Background: The body naturally produces vitamin D after exposure to sunlight and absorbs it from certain foods. In addition to helping the body absorb the calcium and phosphorus needed for healthy bones, vitamin D affects a variety of biological processes by binding to a protein called a vitamin D receptor. This receptor is present in nearly every cell in the body.
“By reviewing studies that collectively examined vitamin D levels in 17,332 cancer patients, our analysis demonstrated that vitamin D levels are linked to better outcomes in several types of cancer,” said one of the study’s authors, Hui Wang, MD, PhD, Professor of the Institute for Nutritional Sciences at the Shanghai Institutes for Biological Sciences at the Chinese Academy of Sciences in Shanghai, China. “The results suggest vitamin D may influence the prognosis for people with breast cancer, colorectal cancer and lymphoma, in particular.”
The Evidence: The meta-analysis (study of studies) looked at the results of 25 separate studies that measured vitamin D levels in cancer patients at the time of diagnosis and tracked survival rates. In most of the research, patients had their vitamin D levels tested before they underwent any treatment for cancer. The study found a 10 nmol/L increase in vitamin D levels was tied to a 4 percent increase in survival among people with cancer.
Researchers found the strongest link between vitamin D levels and survival in breast cancer, lymphoma and colorectal cancer. There was less evidence of a connection in people with lung cancer, gastric cancer, prostate cancer, leukemia, melanoma or Merkel cell carcinoma, but the available data were positive.
“Considering that vitamin D deficiency is a widespread issue all over the world, it is important to ensure that everyone has sufficient levels of this important nutrient,” Wang said. “Physicians need to pay close attention to vitamin D levels in people who have been diagnosed with cancer.”
My Take: Many studies have established an association between low levels of vitamin D and a myriad of illnesses (for example, multiple sclerosis, macular degeneration, colon cancer, breast cancer, rheumatoid arthritis, heart disease, and more. Those closer to the equator appear to have lower incidences and death rates for certain cancers. Because exposure to ultraviolet light from sunlight leads to vitamin D production, researchers have wondered whether variation in vitamin D levels might be responsible for this association.
However, causality has not been established. Whether you can lower your risk of these diseases by increasing your vitamin D intake remains unknown. I am not enthusiastic about across-the-board recommendations regarding amounts for intake, since your blood vitamin D levels may depend on your weight, skin color, sun exposure, diet, genetics, and other factors. I do not think it is unreasonable to consider checking your blood level of vitamin D. With vigorous supplementation, your blood vitamin D levels may become toxic (too much vitamin D raises calcium levels, which can cause calcinosis – calcium is deposited in soft tissues such as the kidneys, heart, and lungs). On the other hand, many have levels that are too low. The safe upper intake level of vitamin D for adults is around 4000 IU daily (some patients are placed on higher doses, but only temporarily, and with monitoring of blood levels). Finally, excessive exposure to sunlight can increase your risk of skin cancer.
I’m Dr. Michael Hunter.
The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.
Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad: Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minute; Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.
Reference: Endocrine Society. “Vitamin D may raise survival rates among cancer patients.” ScienceDaily. ScienceDaily, 29 April 2014. <www.sciencedaily.com/releases/2014/04/140429133456.htm>; Mian Li, Peizhan Chen, Jingquan Li, Ruiai Chu, Dong Xie, Hui Wang. Review:The Impacts of Circulating 25-Hydroxyvitamin D Levels on Cancer Patient Outcomes: A Systematic Review and Meta-Analysis. The Journal of Clinical Endocrinology & Metabolism, 2014; jc.2013-4320 DOI: 10.1210/jc.2013-4320