Vitamin D levels at diagnosis may affect the survival chances of some cancer patients, new research suggests.
Patients with more of the vitamin in their blood tended to have better survival rates and remain in remission longer than those who were deficient, a study found.
Researchers came to the conclusion after analysing the results of 25 separate studies looking at vitamin D and cancer death rates.
Lead scientist Hui Wang, from the Chinese Academy of Sciences in Shanghai, said: “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.
“The results suggest vitamin D may influence the prognosis for people with breast cancer, colorectal (bowel) cancer and lymphoma, in particular.”
Vitamin D, produced naturally in body by exposing the skin to sunlight and absorbed from certain foods, is vital for healthy bones and also influences a wide range of biological processes.
A protein called the vitamin D receptor that is sensitive to the vitamin is found in nearly every cell in the body.
In most of the studies involved in the research, patients had their vitamin D levels tested before undergoing any cancer treatment.
Wang's team found that a 10 nanomole per litre increase in vitamin D blood levels was associated with a 4% greater chance of survival.
The strongest link between vitamin D level and death rate was seen in breast and bowel cancer patients, and those with the blood cancer lymphoma.
There was less evidence of a connection with lung cancer, stomach cancer, prostate cancer, leukaemia, melanoma skin cancer and Merkel cell carcinoma.
“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,” said Wang. “Physicians need to pay close attention to vitamin D levels in people who have been diagnosed with cancer.”
The research is published in the Journal of Endocrinology & Metabolism.