Life Extension Update
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."
Little is known about the causes of pancreatic cancer. The disease is difficult to diagnose in its early stages, as it presents few symptoms and there are few tests to screen for it. As a result, most patients have incurable disease by the time they are diagnosed. Fewer than 5 percent of pancreatic cancer patients survive five years beyond diagnosis of the disease.
Nutritional intervention aims to:
Consuming a diet rich in fruit and vegetables, plus controlling calories by dietary measures or exercise, will help to prevent pancreatic cancer ( Lowenfels AB et al 2004). A constituent of cruciferous vegetables such as watercress called phenethyl isothiocyanate (PEITC) stopped pancreatic cancer from developing in a hamster model that was given a cancer-causing agent (a carcinogen known as BOP) (Nishikawa A et al 2004).
In the news: Increasing vitamin D intake cuts cancer risk; Testosterone benefits male Alzheimer’s patients; Warfarin increases fracture risk in men; DHEA promotes better wound healing; Stem cells may help treat heart disease; High carotenoid, selenium levels reduce mortality risk; Life Extension experts address Antiaging Congress.
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