Life Extension Update Exclusive
Harvard study of professional men finds increased vitamin D levels associated with lower risk of cancer mortality...
The April 5, 2006 issue of the Journal of the National Cancer Institute reported the findings of researchers at Harvard University that higher estimated levels of vitamin D are associated with a decreased incidence of all cancers, particularly those of the digestive system, as well as a decreased risk of dying from the disease.
Edward Giovannucci, MD, of Harvard School of Public Health, and colleagues estimated vitamin D levels for 47,800 men who participated in the Health Professionals Follow-Up Study, an ongoing prospective investigation into the causes of chronic diseases in male health professionals who were 40 to 75 years old upon enrollment in 1986. Dietary and other information was provided by questionnaires completed at the beginning of the study and every four years thereafter, and medical history was updated every two years. Long-term vitamin D levels were estimated from dietary intake and supplementation, skin pigmentation, adiposity, geographic residence, and leisure-time physical activity [this methodology was developed using the plasma 25-hydroxy-vitamin D levels of a subset of 1095 participants, and verified on another group].
Between 1986 and 2000 there were 4,286 cancer diagnoses and 2,025 deaths from the disease. Men whose estimated 25(OH)D (vitamin D) levels were in the top 10 percent of participants experienced a 22 percent lower risk of mortality from any cancer than those in the lowest tenth. The research team found that an increment in vitamin D levels of 25 nanomoles per liter (nmol/L) was associated with a 17 reduction in cancer incidence, a 29 percent reduction in cancer mortality, and a 45 percent reduction in digestive tract (colorectal, pancreatic, esophageal and stomach) cancer mortality.
“Achieving a 25(OH)D increment of 25 nmol/L may require a vitamin D supplementation of at least 1500 IU/day, a safe but not generally encouraged level,” the authors write. “Because current recommendations are adequate only to prevent extremely low vitamin D levels, establishing definitely whether cancer incidence and mortality rates are increased by inadequate vitamin D status should be a high priority.”
In an editorial in the same issue of the JNCI, Gary G. Schwartz, PhD, of Wake Forest University and William J. Blot, PhD, of the International Epidemiology Institute in Rockville, write, "The promising results from both observational and laboratory studies should usher in a new era of intervention studies of vitamin D and cancer risk. Because many public health scientists are already clamoring for higher levels of vitamin D supplementation for bone and other health, randomized trials of vitamin D and cancer risk should be undertaken speedily."
Comment: Receptors for vitamin D have been found all over the body from bone and brain to thymus and uterus. While there is still much to learn, strong evidence suggests that vitamin D is also important as an immune enhancement, anti-cancer and cardio- protective and joint protective agent, as well as being a potent antioxidant.
From an anthropological perspective we evolved outdoors exposed to abundant sunlight with very “high” vitamin D blood levels. Farmers and outdoor workers in sunny climates produce an equivalent of 10,000 IU vitamin D a day from solar radiation. These outdoor folks have naturally high vitamin D blood levels, at, or above the high end of normal for the standard laboratory range. These levels are maintained without any toxic effects, in fact, considerable data suggest health-promoting effects. I take 4,000 IU every day, but I do not get alot of sun.
Add Vitamin D3 to your health program: NSI Vitamin D3 -- 1,000 IU
Christopher Wiechert's Healthblogger is for educational or informational purposes only, and is not intended to diagnose or provide treatment for any condition. If you have any concerns about your own health, you should always consult with a healthcare professional. If you decide to use this information on your own, it's your constitutional right, but I assume no responsibility.
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