been introduced over the years, wherein other flavors (such as wild cherry, vanilla, lemon, and lime) have been added to the cola. A caffeine-free version of Diet Pepsi is also produced. In Australia, this variant is known as Pepsi Light Caffeine Free and has a gold label. It's only available in 1.25 litre bottles, and the ingredients are listed as Carbonated Water, Caramel Color, Phosphoric Acid, Aspartame, Sodium Benzoate, Acesulfame Potassium, Flavour (Natural), and Citric Acid. The availability and brand identification of Diet Pepsi flavor variants varies by country. In addition to Diet Pepsi, PepsiCo also produces the low-calorie colas Pepsi Max and Pepsi Zero Sugar, depending on the country. Composition In the United States, Diet Pepsi is marketed as having zero calories, as FDA guidelines categorize products with fewer than five calories per serving to be labeled as containing "zero calories". Though Diet Pepsi is represented worldwide as a low- or no-calorie beverage, the ingredients comprising its makeup vary in some cases by the country of origin. In the US, its ingredients are recorded as "carbonated water, caramel color, aspartame, phosphoric acid, potassium benzoate (preserves freshness), caffeine, citric acid, natural flavor, acesulfame potassium; phenylketonurics: contains phenylalanine". In Canada, the ingredient listing reads: "carbonated water, caramel color, phosphoric acid, aspartame (124 mg/355 ml, contains phenylalanine), sodium benzoate, caffeine, flavor, acesulfame potassium (32 mg/355ml), citric acid, dimethylpolysiloxane". Comparatively in the UK, Diet Pepsi is listed as consisting of "carbonated water, colour (caramel E150d), flavorings (including caffeine), phosphoric acid, sweeteners (aspartame, acesulfame K), acidity regulator (sodium citrate), preservative (sodium benzoate), citric acid, contains a source of phenylalanine". The initial formulation of Diet Pepsi was sweetened with the artificial sweetener saccharin, although concerns over saccharin emerged in the 1970s, prompting a shift to an alternative sweetener, aspartame, which was marketed as the brand NutraSweet, in 1983. Aspartame has been the subject of controversy, most notably in 1996 following a 60 Minutes report on concerns alleging that aspartame might be linked to the development of brain tumors in humans. Critics of aspartame have expressed concerns that numerous health risks may be associated with its consumption; however, peer-reviewed comprehensive review articles and independent reviews by governmental regulatory bodies have analyzed the published research on the safety of aspartame and have described it as safe for consumption at current levels. Aspartame has been deemed safe for human consumption by regulatory agencies in their respective countries, including