Ingredients in Diet Sodas

Diet sodas are commonly marketed to people with diabetes, people wanting to cut back on sugar and people reducing their calories in an effort to lose weight. Diet sodas contain many of the same ingredients as regular sodas, with the primary differences being the ingredients used to sweeten the beverages and certain preservatives. Diet sodas typically contain fewer calories than regular soda. Manufacturers often use low-calorie or zero-calorie sweeteners to keep the calorie content on the low end.

Don't drink a lot of diet soda. (Image: nd3000/iStock/Getty Images)

Artificial Sweeteners

Sucralose, acesulfame K and aspartame are three artificial sweeteners commonly found in diet sodas. Sucralose is a zero-calorie sweetener that is 600 times sweeter than sugar and aspartame is 200 times sweeter than sugar. Acesulfame K is about 150 to 200 times sweeter than sugar and is typically found in combination with aspartame or other artificial sweeteners because it acts to enhance and sustain the flavor of sweet foods.

Caffeine Content

Diet sodas typically contain caffeine in amounts comparable to that of regular sodas. For example, diet Mountain Dew, Diet Coke, Diet RC and Diet Pepsi contain 55, 45, 43 and 36 milligrams of caffeine respectively. These amounts are the same as, or very similar to, the regular versions. Caffeine is considered safe in moderate amounts of 100 to 200 milligrams per day, although tolerance varies from person to person.

Phosphoric Acid

Many sodas, including diet soda, contain phosphoric acid, which is a mineral acid composed of phosphorus. Phosphoric acid gives soda its acidity and tart, sharp flavor. In fact, almost all of the acidity in soda comes from phosphoric acid, according to Frostburg State University. Phosphoric acid is corrosive and drinking sodas regularly has long been linked to an increased risk of dental erosion. However, the acid concentration in the typical soda is lower than that of orange juice or lemonade, according to FSU.

Preservatives and Artificial Colorings

Diet sodas typically contain the preservative potassium benzoate, which is primarily used to preserve the freshness of diet foods. Manufacturers add it to diet soda to prevent mold from growing while the soda is on store shelves. Like regular soda, diet soda often contains artificial dyes, which add color to the beverage. The Food and Drug Administration has approved nine artificial colors in the U.S. Before food additives such as artificial colors are approved, the FDA evaluates them to ensure they are safe for human consumption.