THE FACTS Millions of Americans take multivitamins daily, looking to get all sorts of health benefits. But when it comes to a good night’s sleep, can these pills do a disservice?

Over the years, anecdotal reports have suggested as much, with some users claiming that multivitamins shorten sleep and lead to more frequent awakenings in the middle of the night. In one study in 2007, researchers recruited hundreds of subjects and investigated their sleep habits  including looking at their use of vitamins and medications  then had them keep sleep diaries for two weeks.

Image Credit... Christoph Niemann

After controlling for age, sex and other variables, the scientists found a slightly higher rate of poor or interrupted sleep in people taking multivitamins. But because they found only an association, they could not rule out the possibility that people with poorer sleep are simply more likely to seek out multivitamins.