PepsiCo said it would replace its current Diet Pepsi offerings in the United States with those free of aspartame, an artificial sweetener that has come under scrutiny from health-conscious consumers.

Diet Pepsi, Caffeine-Free Diet Pepsi and Wild Cherry Diet Pepsi sweetened with a blend of sucralose and acesulfame potassium will begin replacing current offerings in August, the company said on Friday.

U.S. sales of carbonated soft drinks have been declining for nearly a decade, with consumers shifting away from diet soda because of perceived health concerns about artificial sweeteners, specifically aspartame.

"Diet cola drinkers in the U.S. told us they wanted aspartame-free Diet Pepsi and we're delivering," Seth Kaufman, senior vice-president of the Pepsi and flavors portfolio within the company's North America beverages business, said in a statement.

Sales in PepsiCo's beverage business have been hurt by a long-term decline in soft drink sales in the United States.

Aspartame, which is about 200 times sweeter than sugar, is widely used to sweeten diet sodas. It is also used by rival Coca-Cola Co in its drinks such as Diet Coke, Coke Zero and Schweppes Diet Lemonade.