Nationwide Mutual Insurance Co. says it’s keeping tabs on allegations that Denver Broncos quarterback and Nationwide company spokesman Peyton Manning used performance-enhancing drugs banned by the National Football League, the Columbus Business Journal reported. According to an Al-Jazeera report Sunday, Manning received human growth hormone from an anti-aging clinic in Indianapolis to recover from neck surgeries in 2011. Manning has vehemently denied the report. Columbus-based Nationwide, which spends millions annually on sports marketing, has had ties with the NFL and Manning since signing separate sponsorship deals in the summer of 2014.