Is the Artificial Sweetener Acesulfame Potassium Safe?

Acesulfame potassium, also called acesulfame K or Ace-K, is one of six artificial sweeteners that have been approved for use in the United States, according to the U.S. Food and Drug Administration (FDA). The other five are sucralose, saccharin, aspartame, neotame and advantame.

The main benefit of so-called nonnutritive sweeteners — which don't provide any vitamins, minerals or any other nutritional benefits — is that they "provide little, if any, calories," Nancy Farrell Allen, RDN, spokesperson for the Academy of Nutrition and Dietetics, tells LIVESTRONG.com.

Ace-K specifically, she adds, "has a good shelf life and is stable in food-preparation methods." That means it doesn't lose its flavor over time, maintaining its sweetness even when heated (which means it can be used in baked goods).

All six of the artificial sweeteners approved by the FDA are considered "high-intensity" sweeteners because they are all much sweeter than regular sugar (sucrose). Ace-K is 200 times sweeter than sugar, says the FDA.

Read more: All the Different Types of Sweeteners and Sugar Substitutes You Need to Know About

The FDA first approved acesulfame potassium in 1988 for use in chewing gum, beverages (including instant coffee and tea), gelatins and puddings. It was also approved for use as a sugar substitute as long as each packet contained no more than the equivalent of two teaspoonfuls of sugar, according to the original FDA approval. At the time, the FDA did not approve Ace-K for confections or hard or soft candy.

In 2003, the FDA expanded its approval of Ace-K so it could be used as a "general-purpose sweetener and flavor enhancer in food, not including meat and poultry." The compound is now found in a wide variety of foods and beverages including all the original food categories plus baked goods, frozen desserts, protein shakes and diet beverages, says Farrell Allen. It's also found in some soft and hard candies and other sweets.

Ace-K is best when combined with other sweeteners as it can leave a slight bitter aftertaste, says Farrell Allen.

You can find Ace-K sold under the brand names of Sunett and Sweet One. It's listed on the ingredient panel of food products in the U.S. as either acesulfame K, acesfulame potassium or Ace-K, says the FDA, or sometimes as E950 in Europe.

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In 1980, the FDA banned the artificial sweetener cyclamate because of a concern that it might cause bladder cancer in laboratory animals, according to the National Cancer Institute. Subsequent studies didn't find the same risk but cyclamate is still banned, and other artificial sweeteners have raised the same worries.

So far, Ace-K and the other five approved sweeteners do not show any evidence of causing cancer. "Despite controversy in test results, the FDA and the European Union maintain that Ace-K is safe for consumer use," says Farrell Allen. "FDA listed it as a Grade I suggesting 'good/strong evidence supporting' its safety."

The FDA's approval of Ace-K was based on an analysis of several studies, most of them on animals, looking at the compound's effect on reproduction, metabolism, genetics and cancer, among other things. They showed no harm and also indicated that Ace-K isn't metabolized by the body. In other words, it is eliminated with other waste. However, note that Ace-K is not approved in meat or poultry because, the FDA says, there isn't enough data.

The National Cancer Society points out that the FDA didn't find any evidence that Ace-K caused cancer.

Read more: 10 Foods That Are Linked to a Higher Cancer Risk

Not everyone agrees that Ace-K is safe. The Center for Science in the Public Interest (CSPI), a consumer watchdog group, has put Ace-K on its list of substances to avoid, saying the existing studies are dated and had significant flaws. CSPI has asked the FDA to conduct more studies.

More recently, researchers, including the authors of a 2017 article in the journal PLOS One, have raised concerns that artificial sweeteners in general may actually contribute to obesity and glucose metabolism. The PLoS One study found changes in the gut microbiome of mice who were given acesulfame potassium. They also reported that the compound was linked with weight gain in male mice, though not female mice.

Read more: What Are the Dangers of Splenda, Sucralose and Aspartame?

In 1988, the FDA determined that the acceptable daily intake (ADI) of acesulfame potassium was 15 milligrams for each kilogram (2.2 pounds) of body weight per day. According to the FDA, this amount of Ace-K would be safe if consumed every day over a lifetime. The 2003 ruling did not change the ADI for Ace-K.

This ADI amounts to around 900 milligrams of Ace-K a day for a 130-pound person, which would take drinking two gallons of beverages containing acesulfame potassium, according to the International Food Information Council Foundation.

Read more: The Ultimate Guide to Natural Sweeteners