(RxWiki News) Vitamin D is an important nutrient that affects bone, tissue and cell growth. Vitamin D deficiency is common around the world, especially among cancer patients.
A recent review of studies found that higher levels of vitamin D in cancer patients before starting treatment were associated with improved overall survival, better disease-free survival for various cancer types and reduced cancer-specific death.
The researchers determined that these associations were strongest among patients with breast cancer, lymphoma and colorectal cancer.
"Discuss the potential benefits of vitamin D with your oncologist."
The lead authors of this review were Mian Li and Peizhan Chen from the Key Laboratory of Food Safety Research at the Chinese Academy of Sciences in Shanghai, China.
The review included 25 studies, published between 2007 and 2014, on the association between circulating vitamin D levels at or near the time of cancer diagnosis and outcomes for patients.
These studies involved a total of 17,332 cancer patients. Ten studies were from the United States, nine were from Europe, four were from Asia and two were from Canada.
All of the study participants had their blood vitamin D levels measured before starting treatment.
The results showed that there were significant associations between blood levels of vitamin D prior to treatment and cancer outcomes.
The colorectal cancer patients with blood vitamin D levels in the highest quartile (the top 25 percent of all levels) were 45 percent less likely to die from any cause compared to the colorectal cancer patients with blood vitamin D levels in the lowest quartile.
Breast cancer patients with vitamin D levels in the highest quartile were 37 percent less likely to die from any cause compared to those in the lowest quartile of vitamin D levels.
The researchers found that lymphoma patients who had vitamin D levels in the highest quartile were 52 percent less likely to die from any cause compared to those with levels in the lowest quartiles.
Higher levels of vitamin D were significantly associated with reduced cancer-specific death for the participants with colorectal cancer and lymphoma.
The findings also revealed that higher levels of blood vitamin D improved disease-free remission for the participants with breast cancer and lymphoma.
A 10-nmol/L increase in blood vitamin D levels was associated with 4 percent decreased odds of the participants with any type of cancer dying from any cause.
"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," review co-author Hui Wang, MD, PhD, said in a press statement. "Physicians need to pay close attention to vitamin D levels in people who have been diagnosed with cancer."
This review was limited because some of the studies only measured vitamin D levels once, and they were not taken at the same time in each study. Also, the quartiles of vitamin D levels contained different ranges of levels from study to study. Lastly, the review's findings were based off of observational trials, so the researchers could not determine a cause-and-effect relationship.
This review was published on April 29 in the Journal of Clinical Endocrinology & Metabolism.
This research was funded by the Ministry of Science and Technology of China, the National Nature Science Foundation, the Science and Technology Commission of Shanghai Municipality, the Director Foundation, the Institute for Nutritional Sciences, Shanghai Institute for Biological Sciences, the Chinese Academy of Sciences and the Sanofi Aventis-Shanghai Institute for Biological Sciences.