Vitaminwater has too much sugar to be accurately described as nutritious, Britain's ad regulator ruled Wednesday, ordering brand owner Coca-Cola to stop publicizing the claim.

Britain's ad watchdog is challenging Coke's nutrition claims for its Vitaminwater. (Mark Lennihan/Associated Press)

The Advertising Standards Authority said Coca-Cola broke ad rules when it described its popular line of flavoured water products as "delicious and nutritious" in an ad last summer, explaining that consumers wouldn't expect a drink marketed as nutritious to have between four and five teaspoons of added sugar.

The Coca-Cola Co. said it's disappointed by the ruling, although it won't face any further action as long as it doesn't run the ad again.

The ruling is little more than a regulatory rap on the knuckles, but underlines transatlantic concerns about the way in which Vitaminwater is marketed.

In the United States, consumers and health advocacy group Center for Science in the Public Interest are suing over claims that Coca-Cola is using deceptive labelling to sell the drinks. In July, a district court judge wrote that Vitaminwater's use of the word "healthy" violated Food and Drug Administration labelling rules.

Vitaminwater is made by New York-based Glaceau, which was bought by Coca-Cola in a $4.1-billion US deal in 2007.