Vitamin D supplements are widely recommended to prevent bone fractures in older adults — but a clinical trial, published Wednesday in the New England Journal of Medicinefound that they may not do much after all.
In 2011, the National Academy of Medicine (then called the Institute of Medicine) recommended the general public get between 600 and 800 international units (IU) of vitamin D daily. That recommendation was based on past research showing that the vitamin may support bone health by aiding in calcium absorption and decreasing bone turnover, which causes bone deterioration.
Subsequent studies have yielded contradicting results; some concluded supplementing with vitamin D was beneficial, while one even found that high vitamin D levels caused by taking supplements could be harmful and cause more falls. Other trials have looked at both calcium and vitamin D together, making it difficult to analyze the vitamin’s effects on its own.