The Agency for Healthcare Research and Quality (AHRQ) issued a new evidence report on vitamin D and bone health in August. Following its release, the report, “Effectiveness and Safety of Vitamin D in Relation to Bone Health,” served as a framework for a National Institutes of Health (NIH) conference held in early September, which examined a range of scientific perspectives related to vitamin D and bone health across the lifecycle.

“This independent, systematic review is timely because there are mixed messages and recommendations to consumers regarding the benefits and harms of vitamin D intake,” said NIH Office of Dietary Supplements (ODS) director, Paul Coates, PhD. “The evidence report in combination with the conference presentations and discussions, newly available methodological tools, and newer information on the vitamin D status of the U.S. population will provide an invaluable and very timely update for the research and public health communities of what we know and what we need to know for this key nutrient.”

Researchers have long known that vitamin D impacts bone health, but there is uncertainty about how much vitamin D is needed to achieve optimal bone health and whether there are differences in the relationship of vitamin D status to bone health across age and life stage groups. This report highlights the fact that the largest amount of evidence for bone health benefits is in postmenopausal women and older men (the majority over 60 years of age) taking vitamin D supplements. This report also confirms that vitamin D from ultraviolet-B (sunlight) exposure, fortified foods, or dietary supplements are all effective in raising the level of circulating vitamin D. Of concern, there were only sparse data on other subgroups cited as being at high risk for the consequences of low vitamin D, such as dark-skinned individuals and pregnant and lactating women.

The report also found it difficult to define specific blood levels of markers for vitamin D status that indicate optimal levels for bone health. One reason for this is that current methods, which measure serum-25-hydroxy vitamin D as the marker for vitamin D status, yield highly inconsistent results. As part of its broader vitamin D initiative, ODS is working with laboratory testing facilities to standardize the quantification of vitamin D status.

Further, report investigators were not able to separate the impact of vitamin D from that of calcium, as most trials studied the effect of vitamin D plus calcium. The combination of vitamin D3 (daily dose 700 to 800 IU) and calcium (daily dose 500 to 1200 mg) decreased the risk of falls, fractures and bone loss in the elderly, ranging in age from 62 to 85 years old. The current recommended intake is 400 IU per day for people 51 to 70 years of age, and 600 IU per day for people over 70 years of age. Based on the combined data of two trials, the decreased risk of fractures was seen primarily in the subgroup of elderly women (average age 85 years) living in nursing homes.

The vitamin D conference held last month evaluated the efficacy and safety of vitamin D, identified gaps in knowledge on the efficacy and safety of vitamin D, and informed NIH and other Federal agencies on vitamin D and health research priorities. According to Lisa Ahramjian at the Office of Disease Prevention at the NIH, the conference proceedings will be published in the American Journal of Clinical Nutrition in the coming months.