The market for carbonated soft drinks, diet and nondiet, was worth nearly $73 billion in the United States in 2008, according to “Beverage Digest.” Many of these beverages contain phosphoric acid, a substance that has a possible link to several health problems. Drinking sodas in moderation might be safe, but if you tend to drink a lot of colas, you might want to rethink your choices the next time you reach for a soda can.