Multivitamins have ignited a fierce scientific debate over whether nutritional supplements are beneficial to our health or a multi-billion-dollar racket . A long-term randomized controlled trial in the United States has now produced some of the strongest evidence to date that nutritional supplements may slow aging. "A lot of people take a multivitamin without necessarily knowing any benefits from taking it, so the more we can learn about its potential health benefits, the better," says senior