Among patients diagnosed with colorectal cancer, those with higher levels of vitamin D in their blood prior to diagnosis have an improved survival compared with those with lower levels. These results were recently published in the Journal of Clinical Oncology.
Vitamin D is a fat-soluble vitamin that comes from dietary supplements, foods such as fortified milk and cereal, certain kinds of fish (including salmon, mackerel, and tuna), and exposure to sunlight. Vitamin D is thought to play a role in the prevention of some types of cancer.
Results from previous trials have indicated that individuals with higher levels of vitamin D in their blood have a reduced risk of developing colorectal cancer. The effects of vitamin D on outcomes of patients already diagnosed with colorectal cancer, however, are unknown. Because colorectal cancer remains the second leading cause of cancer-related deaths, studying the effects of dietary and exercise habits on outcomes has become a source of extensive research.
Researchers from Harvard University recently conducted a study to further explore the potential relationship between vitamin D levels in the blood and their effects on outcomes of colorectal cancer. The study included 304 participants in the Nurses’ Health Study and Health Professionals Follow-Up Study (HPFS) who had been diagnosed with colorectal cancer between 1991 and 2002. Blood samples were drawn when the trial began, prior to the diagnosis of colorectal cancer.
- Higher levels of vitamin D in the blood prior to diagnosis of colorectal cancer were associated with a significantly increased overall survival.
- Patients with higher levels of vitamin D in the blood prior to diagnosis of colorectal cancer also had a reduction in death caused by colorectal cancer.
The researchers concluded: “Further study of the vitamin D pathway and its influence on colorectal [cancer] and cancer progression is warranted.”
Reference: Ng K, Meyerhardt J, Wu K, et al. Circulating 25-hydroxyvitamin D levels and survival in patients with colorectal cancer. Journal of Clinical Oncology. 2008;26:2984-2991.