It is commonly accepted that people with diabetes can drink artificially sweetened soft drinks — diet soda, to most people — without risk of raising their blood glucose level. This belief is based on the American Dietetic Association’s categorization of diet soda as a “free food,” which means that it contains less than 20 calories and 5 grams of carbohydrate per serving.
But new research suggests that consumption of diet soda may not be as harmless as the conventional wisdom holds. Although diet sodas don’t directly raise blood glucose level, several recent studies have concluded that people who drink diet soda daily have a higher risk of developing Type 2 diabetes as well as metabolic syndrome, a term used to describe the common combination of high blood pressure, abnormal blood lipid (cholesterol and triglyceride) levels, insulin resistance, and excess abdominal fat.
These puzzling findings certainly fly in the face of accepted nutrition science, and they raise the question: How could beverages so low in calories and carbohydrate increase the chance of developing Type 2 diabetes and its related risk factors?
Types of sweeteners
Diet sodas (as well as some other beverages and food products) are currently sweetened with a variety of types of low-calorie sweeteners, including the following:
Saccharin is one of the oldest artificial sweeteners still in use and has been on the market since 1977. It is the sweetening agent found in Sweet’N Low. Although use of saccharin has declined somewhat during the past 20 years, it is still used — along with aspartame — to sweeten the popular diet soda Tab.
Aspartame, the sweetener found in Equal and NutraSweet, has been in use since 1981. It is 200 times sweeter than sugar and is widely used in sodas and snack foods. Because it breaks down into its chemical components — phenylalanine and aspartic acid — in the body, aspartame should not be consumed by individuals who have phenylketonuria, a rare genetic disease in which the body is unable to process phenylalanine. If unchecked, this disorder can result in seizures, developmental problems, and brain damage. (In most US states, newborns are routinely screened for phenylketonuria.)
Acesulfame potassium (often called acesulfame K) was approved by the US Food and Drug Administration (FDA) in 1988. It is about 180 times sweeter than sugar. Because it has a slightly bitter aftertaste, acesulfame K is usually blended with other sweeteners for use in beverages and foods. It is sold under the names Sunett and Sweet One.
Sucralose is the artificial sweetener found in Splenda. It has been used since 1998 and is about 600 times sweeter than sugar. It is often used in baked goods and snack foods (as well as diet beverages) because it does not break down when heated.
Stevia is a sweetener that, unlike the others listed here, is not synthetically produced. It is derived from the leaves of stevia rebaudiana, an herb grown in Brazil and Paraguay that is related to the daisy plant. A component of the stevia leaf, rebaudioside A, was recognized by the FDA as safe for use in foods and beverages in December 2008. This sweetener can be found in Sprite Green and Zevia low-calorie sodas and is also available in single-serving packets under the brand names Truvia, PureVia, OnlySweet, and Stevia Extract in the Raw. Another brand of stevia sold in single-serving packets, SweetLeaf, contains both rebaudioside A and another purified stevia component called stevioside. According to information from the company, SweetLeaf was given the go-ahead by the FDA to sell this product as a food ingredient in August 2009. Stevia products that contain the whole leaf or other, less-purified extracts of stevia are sold as dietary supplements, not sweeteners.