The idea made so much sense it was almost unquestioningly accepted: Vitamin D pills can protect bones from fractures. After all, the body needs the vitamin for the gut to absorb calcium, which bones need to grow and stay healthy.
But now, in the first large randomized controlled study in the United States, funded by the federal government, researchers report that vitamin D pills taken with or without calcium have no effect on bone fracture rates. The results, published Thursday in The New England Journal of Medicine, hold for people with osteoporosis and even those whose blood tests deemed them vitamin D deficient.
These results followed other conclusions from the same study that found no support for a long list of purported benefits of vitamin D supplements.