But after reviewing nearly 1,000 studies and taking testimony from experts, the report concluded that “information about the health benefits beyond bone health…were from studies that provided often mixed and inconclusive results and could not be considered reliable.”

And the authors said that recent reports suggesting that many people don’t get enough of the vitamin might reflect flawed screening tests and protocols, not true deficiency. “The number of people with vitamin D deficiency in North America may be overestimated because many laboratories appear to be using cut-points that are much higher than the committee suggests is appropriate,” said the IOM report. Still, the report noted that some groups, notably older adults living in institutions and those who have dark skin, might be at increased risk of vitamin D deficiency.

Likewise, most people get enough calcium, the report said. The lone exception: girls 9 to 18. Post-menopausal women actually often get too much of the mineral, putting them at greater risk for kidney stones. The IOM report notes the dangers associated with taking too much of either nutrient. “Higher levels have not been shown to confer greater benefits, and in fact, they have been linked to other health problems, challenging the concept that ‘more is better.’ ”

Bottom Line: We applaud the IOM’s actions, which will help clear up confusion about how much vitamin D people need and establish some much needed standards for testing. And its emphasis on the potential risks of very high doses provides an important and often neglected cautionary message. The table below shows the new recommendations for vitamin D and calcium below. See our recommendations for how to get enough vitamin D and calcium.

—Kevin McCarthy, associate editor