Calcitriol is known to be involved in the immune system, calcium and bone metabolism, and regulation of gene expression; hormone D is linked to prevention and treatment of osteoporosis, cancer, diabetes, and other diseases of aging, including tooth attachment, muscle function and inadvertent falls which can result in bone fractures. A growing amount of research suggests that vitamin D may be beneficial to cancer patients. Recently experts believe that that current governmental guidelines in all countries with respect to how much daily vitamin D is required simply to maintain bone health and health in general are too low and do not reflect the many scientific advances made in vitamin D and hormone D research over the past 10 years. There are guideliens for supplementation but not in cacner patients. The American Academy of Pediatrics (AAP) doubled the amount of vitamin D it recommends for infants, children and adolescents. Current guideliens are current vitamin D guidelines of 200 to 600 daily. The Skin Cancer Foundation has revised its vitamin D recommendations for adults who have limited sun exposure or who practice photo protection to increase their amount of daily vitamin D from 400 to 1000 international units (IUs). BC Cancer Agency recommends daily intake for calcium is 1500 mg for postmenopausal women and 1000 mg for premenopausal women. A daily supplement of 1000 IU of vitamin D is recommended for bone health and the prevention of cancer, in all women. However, cancer patients are more prone to hypervitaminosis D.
Even though there are some minor disagreements about specific cut points, most experts suggest that a blood level of 25-OHD, considered to be the best marker of vitamin D status, of approximately 75 nmol/L (30 ng/mL) is required for vitamin D sufficiency. Unfortunately, the standard supplementary dose has not been established, or whether supplementation should or should not be guided by blood levels of Vit. D.
Goodwin PJ.Vitamin D in cancer patients: above all, do no harm.J Clin Oncol. 2009 May 1;27(13):2151-6.
Anthony W. Norman et al, 13th Workshop consensus for vitamin D nutritional guidelines The Journal of Steroid Biochemistry and Molecular Biology, Volume 103, Issues 3-5, March 2007, Pages 201-203