ABCNews -- In recent years, both research on and the availability of vitamin supplements has increased, drawing increased attention to the possibility that a daily pill can enhance health. In particular, it is a message that is resounding with men. According to the Council for Responsible Nutrition, 53 percent of American adults take a multivitamin supplements, and 50 percent of adult men 18 and older take a multivitamin, according to a 2008 survey. But preliminary encouraging findings can often hit a wall when they are refuted by larger studies that lead to increased scrutiny on products whose claims overstated the benefits of that early research. The latest product to enter the crosshairs of a watchdog group is Bayer's One A Day Men's Health...