The June, 2007 edition of the American Journal of Clinical Nutrition published the results of a four year trial that revealed a protective effect for vitamin D and calcium against cancer in women. The findings bolster a recent study which uncovered an association between calcium and vitamin D intake and a lower risk of breast cancer.
Researchers at Creighton University in Omaha, Nebraska enrolled 1,179 women aged 55 and older living in a nine-county surrounding area. The participants were randomized to receive 1100 international units vitamin D3 plus 1400 milligrams calcium from calcium citrate or 1500 milligrams calcium from calcium carbonate, calcium only, or a placebo for four years. Serum 25-hydroxyvitamin D levels [25(OH)D] were measured at the beginning of the study and at 12 months.
After one year, vitamin D levels had increased in the calcium plus vitamin D group. By the end of the trial, fifty women had been diagnosed with a nonskin cancer, including 13 during the first year of the study. Cancers included breast, colon, lung, and other cancers. While women who received calcium alone had a 47 percent lower risk of developing cancer over the course of the trial compared with subjects who received the placebo, those who received both calcium and vitamin D experienced a 60 percent lower risk. When subjects whose cancers were diagnosed during the first year of the study were excluded from the analysis, due to the possibility that their cancers were pre-existing upon enrollment, the reduction in risk associated with calcium plus vitamin D was further lowered to 77 percent less than the placebo group.
â€śImproving vitamin D nutritional status substantially reduced all-cancer-risk in postmenopausal women,â€? the authors conclude. â€śFurthermore, baseline and treatment-induced serum 25(OH)D concentrations were themselves strong predictors of cancer risk. These findings highlight the importance of promoting optimum vitamin D status and underscore the value of achieving and maintaining a high serum 25(OH)D concentration.â€?
Lead author and Creighton University nutrition researcher Dr Joan Lappe announced, â€śThis is the first clinical trial to show that boosting vitamin D status can affect the overall risk for cancer â€“ a proposition that has tremendous public health potential. By choosing vitamin-D rich foods like milk and taking a supplement Americans can help improve their vitamin D levels and potentially impact their cancer risk.â€?
Related Health Concern: Complementary alternative cancer therapies
Complementary alternative medical therapies (CAM) is a collective term for an array of remedies that lie outside what is traditionally considered conventional medical treatment for cancer. These include the use of herbal, vitamin, and nutritional supplements, as well as physical and psychological interventions such as exercise, relaxation, massage, prayer, hypnotherapy, and acupuncture (Deng G et al 2005; Hann D et al 2005; Molassiotis A et al 2005). The use of CAM as a component of integrated cancer treatment regimens may help patients reduce the side effects associated with conventional cancer treatments, alleviate symptoms, enhance immune function, and provide greater quality of (and control over) life (Deng G et al 2004, 2005).
In clinical studies involving more than 1000 colorectal cancer patients, calcium supplements reduced the risk of cancer recurrence (Shaukat A et al 2005). Other studies show that calcium supplements generally reduce the risk of developing colorectal cancer in the first place (Flood A et al 2005; Sandler RS 2005). This beneficial effect of calcium was noted for calcium obtained from both dietary sources and nutritional supplements (Flood A et al 2005).
Insufficient vitamin D levels are particularly associated with increased risk of developing breast, colon, and prostate cancers (Chen TC et al 2003; Studzinski GP et al 1995). Increased vitamin D levels, obtained through sun exposure, are associated with a reduced risk of non-Hodgkinâ€™s lymphoma (Hughes AM et al 2004). Vitamin D causes bones to release calcium and can thus lead to excessively high calcium levels (hypercalcemia); however, scientists are developing synthetic versions of natural vitamin D (deltanoids) that lack this adverse side effect (Agoston ES et al 2006; Guyton KZ et al 2003).