Which Diet Sodas Do Not Contain Aspartame?

Sometimes you want something a bit more pizazzy than water — like a diet soda. But if you have a rare hereditary disorder known as phenylketonuria (PKU), you need to limit your intake of phenylalanine, found in aspartame.

Fortunately, there are some diet sodas without aspartame.

Aspartame is a sugar substitute about 200 times sweeter than table sugar, so just a small amount is needed to sweeten foods or beverages.

Although it contains 4 calories per gram — the same number of calories in sugar — far less is needed to achieve sweetness, according to the International Food Information Council Foundation. So, it adds negligible calories to food.

It's one of the most popular artificial sweeteners, according to the University of Alabama at Birmingham. Aspartame is composed of aspartic acid and phenylalanine, two amino acids.

The U.S. Food and Drug Administration (FDA) approved the use of aspartame in carbonated beverages in 1983, and many other leading global health agencies, including the World Health Organization, Health Canada and the European Food Safety Authority approve its use in foods and beverages.

The FDA says the acceptable daily intake for aspartame is 50 milligrams per kilogram of body weight, per day. This means that a person who weighs 150 pounds can safely take in 3,400 milligrams of the artificial sweetener — or about 19 cans of diet soda — every day.

Aspartame is not safe for some people, though. A hereditary disorder called PKU requires you strictly limit your intake of phenylalanine, one of the components of aspartame. Always choose diet drinks without aspartame if you have this condition.

The amino acids phenylalanine and aspartic acid are present in natural foods, however, so aspartame isn't the only source. In fact, it's been found that one cup of cow's milk has 0.70 milligrams of aspartic acid, per an October 2021 study in ‌Foods,‌ which could be more than some drinks sweetened with aspartame.

The American Cancer Society notes that some rumors pointing to aspartame causing cancer do exist, but affirms that major health organizations have not found this to be true.

Current evidence shows that low- and no-calorie sweeteners and beverages, including those containing aspartame, are ‌not‌ associated with an increased risk of cancer in humans, per an April 2019 meta-analysis in ‌Regulatory Toxicology and Pharmacology‌.

Although federal agencies still support the safety of taking in aspartame at the level of 50 milligrams per kilogram of body weight per day, recent research brings the safety of the sugar sweetener into question.

A June 2018 paper in ‌Nutritional Neuroscience‌ found that aspartame has been linked to behavioral and cognitive problems — such as headaches, irritable mood, depression and insomnia. Aspartame acts as a chemical stressor, which can have adverse effects on brain health. The researchers advise that aspartame be approached with caution and that more research about the effects of aspartame on brain health is needed.

A September 2017 review in ‌Nutrition Journal‌ noted that there are numerous evidence gaps related to the health effects of nonnutritive sweeteners, including aspartame, so more research is necessary to affirm their safety.

Reduced and no-sugar versions of drinks provide a way to cut back on sugar without having to give up the beverages you enjoy.

Even though major health organizations haven't come out against aspartame-containing drinks, you may choose to avoid them in an abundance of caution.

From Coca-Cola, for example, Diet Coke with Splenda or Coca-Cola Life are options for diet soda without aspartame. Splenda is an artificial sweetener made from sugar. The chemical structure is altered so that much of it passes through your body undigested and unabsorbed.

Coca-Cola Life is sweetened with a blend of cane sugar and stevia leaf extract. Stevia is a naturally sweet plant that can be used to offer noncaloric sweetening. Coca-Cola Life has 35 percent fewer calories than traditional Coke and less added sugar.

Aspartame is still present in the Coca-Cola products Diet Coke, Fanta Zero, Fresca and Coke Zero. Note that other diet sodas from Pepsi, including Diet Mountain Dew and Diet Mug root beer, contain aspartame.

Other soda manufacturers offer aspartame-free diet sodas that can satisfy your desire for a bubbly drink without the artificial sweetener and still no calories. Zevia, for example, uses stevia leaf extract to sweeten all of their soda products. Flavors include traditional cola, but also fruit options such as black cherry and orange as well as ginger ale, root beer and cream varieties.

Hansen's diet sodas are sweetened with sucralose and ace-K and contain no aspartame. Hansen's flavors include cola, vanilla, pomegranate, strawberry and ginger ale, among others.