Kidneys
A team from the National Institutes of Health investigated the dietary habits of 465 people with chronic kidney disease and 467 healthy subjects. The results, published in the journal “Epidemiology” in July 2007, found that drinking two or more colas a day, diet or regular, was associated with a twofold risk of developing kidney disease. The clear sodas that contained citric acid didn’t have the same risk. The researchers weren't able to pinpoint an exact cause for the results, although they noted that phosphoric acid has been associated with urinary changes that promote kidney stones.