I was already considering raising my daily vitamin D intake to 2000iu, and now this:
Review finds current vitamin D recommendations insufficient to achieve healthy blood levels
A review published in the July, 2006 issue of the American Journal of Clinical Nutrition which sought to determine the optimal serum levels of the major circulating form of vitamin D [25(OH)D] for several health outcomes concluded that it would be necessary to consume at least 1000 international units of vitamin D per day to elevate blood serum levels in half the adult population to 75 nanomoles per liter, the minimum level that the researchers found to be advantageous for helping to preserve normal bone mineral density and lower extremity function, and aiding in the prevention of periodontal disease, falls, fractures, and colorectal cancer. Although there is evidence for vitamin D in preventing other diseases such as multiple sclerosis, tuberculosis, insulin resistance, osteoarthritis, hypertension, and cancers other than colorectal cancer, the authors did not include these diseases in the current review.
H. A. Bischoff-Ferrari of Harvard School of Public Health in Boston and University Hospital Zurich in Switzerland, along with colleagues at Harvard and Tufts University evaluated clinical trials and meta-analyses involving vitamin D and each of the selected health outcomes. They concluded that the most desirable serum levels of vitamin D began at 75 nanomoles per liter (30 nanograms per milliliter), and optimal levels are between 90 and 100 nanomoles per liter. These levels cannot be reached by most individuals with the current recommended intakes of 200 international units per day for younger adults and 600 international units per day for older adults. To bring vitamin D concentrations in at least 50 percent of the population up to optimal levels, the authors recommend at least 1000 IU vitamin D per day, and they remark that 2000 IU per day may be a safe recommended daily allowance.
“On the basis of this review, we suggest that, for bone health in younger adults and all outcomes in older adults, including antifracture efficacy, lower-extremity strength, dental health, and colorectal cancer prevention, an increase in the current recommended intake of vitamin D may be warranted,” the authors conclude. “Given the low cost, the safety, and the demonstrated benefit of higher 25(OH)D concentrations, vitamin D supplementation should become a public health priority to combat these common and costly chronic diseases.”