Coca-Cola has no plans to remove aspartame from Diet Coke.

Considered safe by the Food and Drug Administration for more than three decades, aspartame is now a sweetener of concern. Upcoming sales of diet soft drinks may provide insight on the level of consumer concern.

This year PepsiCo North America Beverages, Purchase, N.Y., said it plans to remove aspartame from its diet soft drinks. The Coca-Cola Co., Atlanta, has no such plans for Diet Coke.

The International Food Information Council Foundation’s 2015 Food and Health Survey found 37% of American consumers said they are trying to limit or avoid aspartame entirely, which was up from 33% in 2014. Women and college graduates are more likely to avoid the sweetener. Other
artificial high-intensity sweeteners in the study included sucralose, at 25% in 2015 and 21% in 2014, and acesulfame potassium, at 13% in 2015 and 8% in 2014.

“Aspartame is just one sweetener, but it’s the one that seems to get most of the negatives in the press and on YouTube,” said Al Carey, chief executive officer of Americas Beverages for PepsiCo on Feb. 19 at the Consumer Analyst Group of New York Conference.

PepsiCo North America Beverages said its Diet Pepsi, Caffeine Free Diet Pepsi and Wild Cherry Diet Pepsi will be free of aspartame starting in August. A blend of sucralose and acesulfame potassium will sweeten the drinks instead.

Ajinomoto, which sells aspartame, responded to PepsiCo’s decision in an April 30 statement.

“PepsiCo has been clear that this is a marketing move in response to declining sales of the product line rather than a reflection on aspartame’s taste or safety,” Ajinomoto said. “Consumer research shows that 100% aspartame offers consumers the closest possible match to 100% sugar, but without the calories.”

Ajinomoto, which has its North American headquarters in Fort Lee, N.J., said aspartame has been in Diet Pepsi since the 1980s.

“It is unfortunate that claims by Diet Pepsi that the brand’s new formulation is ‘aspartame free’ may unsettle some consumers about aspartame, which is a wholesome and thoroughly tested food ingredient that tastes more like sugar than any other low-calorie sweetener,” Ajinomoto said. “At a time when the government and health care providers are seeking effective ways to help people manage their weight, claims of this sort will be counter productive.”

Sandy Douglas, president of Coca-Cola, spoke about Diet Coke May 12 at the Goldman Sachs Global Staples Forum.

“Consumers are telling us, ‘Don’t change Diet Coke. We love it just the way it is,’” he said. “But at the same time there is a lot of junk science and alarmism around low- and no-calorie sweeteners that we have to address, and most importantly, we have to ask third parties to help us address it because in the end, low- or no-calorie sweeteners are 100% safe.”

About a year ago Minneapolis-based General Mills, Inc. replaced aspartame with sucralose in its Yoplait Light because of consumer requests. Company sales of yogurt remain strong. For the nine-month period ended Feb. 22, 2015, General Mills’ yogurt, ready-to-eat cereal and snacks gained market share in the U.S. retail segment. The company said Yoplait Original Style and Greek yogurt varieties made “particularly strong contributions” to nine-month net sales results, but General Mills made no specific mention of Yoplait Light.

Other sweeteners have faced perception problems. Companies often promote products with “no high-fructose corn syrup,” which has the Corn Refiners Association, Washington, defending that sweetener.

When analyzing the percentages of consumers saying they are avoiding a certain ingredient, know whether the survey is “aided” or “unaided,” according to the Corn Refiners Association. Aided questions give consumers a list of possible answers while unaided questions do not give a list and thus lead to answers reflecting items that are noteworthy enough for consumers to remember without prompting.

In the IFIC survey, people first were given a list of dietary components and ingredients and asked whether or not they “considered” them while making decisions on which foods or beverages to eat/purchase. Then, for the items that they said they considered, they were asked whether they were trying to avoid or consume (on a scale from “trying to avoid altogether” to “trying to get as much as possible”).

PepsiCo North America Beverages said its Diet Pepsi, Caffeine Free Diet Pepsi and Wild Cherry Diet Pepsi will be free of aspartame starting in August.

The association recently released 2015 Sweetener 360, a survey of more than 15,000 consumers conducted by the association and completed in part by Nielsen and Mintel Consulting. The survey found consumers are becoming more mindful of sweeteners and health, but their purchase behavior is not changing. For example, 46% of millennials said it is worth the sacrifice to pay more for food and beverages with sweetener ingredients that are “better for you,” which was the highest percentage of any generation. Yet millennial consumers account for 22% of sales for HFCS-sweetened products while being only 20% of the U.S. population.

Considered safe since 1981

Aspartame’s history in the U.S. market dates to at least 1981 when the F.D.A. approved its use in certain conditions. An F.D.A. aspartame approval for carbonated beverages came in 1983, and the F.D.A. approved it as a “general purpose sweetener” in 1996.

“Aspartame is one of the most exhaustively studied substances in the human food supply, with more than 100 studies supporting its safety,” the F.D.A. said.

However, the European Ramazzini Foundation in 2005 published findings of a study on aspartame conducted in rats. The results indicated aspartame may cause cancer.

Following the study, a European Food Safety Authority panel evaluated aspartame twice, releasing recommendations in 2006 and 2013. Both times the E.F.S.A. found in favor of keeping the acceptable daily intake (A.D.I.) of aspartame at 40 mg per kilogram of body weight per day.

Debate over aspartame’s safety still continues in 2015. The Center for Science in the Public Interest, Washington, said the sweetener caused cancer and tumors in two studies on rats and cancer in one study on mice.

The Calorie Control Council, Atlanta, has said for a 150-lb adult to reach the F.D.A.’s A.D.I. for aspartame of 50 mg per kilogram of body weight, he or she would need to drink 20 carbonated soft drinks in one day. A 50-lb child would need to drink 6 carbonated soft drinks in one day to reach the A.D.I. Aspartame is found globally in more than 6,000 products and consumed by more than 200 million people, according to the Calorie Control Council, an international association representing the low- and reduced-calorie food and beverage industry.