Diet Coke Plus
© The Coca-Cola CompanyRegulators say Diet Coke Plus lacks enough nutrients to justify the word "plus."
The Food and Drug Administration called on Coca-Cola Co. to revise the label on a version of its Diet Coke brand containing vitamins and minerals, warning the beverage giant that it makes inappropriate nutritional claims, according to a warning later posted on the agency's Web site Tuesday.

The FDA said the soft drink, Diet Coke Plus, doesn't contain enough nutrients to qualify for use of the word "plus." Foods may use that name only if they contain at least 10% more of the reference daily intake or daily reference value of a nutrient than a similar product. The FDA also invoked a longstanding rule under which it "does not consider it appropriate" to fortify snack foods such as carbonated beverages.

The warning letter, sent to Coke Dec. 10, comes as a growing number of nutrient-enhanced beverages, from energy drinks to enhanced waters, have appeared on store shelves, putting pressure on the FDA to police more aggressively the claims many of the products make about the benefits they can deliver.

Coke isn't the only company to add nutrients to a soft drink. Cadbury PLC marketed a fortified version of 7UP with calcium, fruit juice and Vitamin C four years ago, and PepsiCo Inc. currently sells Diet Pepsi Max, a diet soda with ginseng.

The FDA called on Coke to "take prompt action to correct these violations" and asked the company to respond within 15 days of receipt of the letter.

A Coke spokesman, Scott Williamson, said the company will respond to the FDA in early January, but that it has no plans to change the label.

"We take seriously the issues raised by the FDA in its letter," he said. "This does not involve any health or safety issues, and we believe the label on Diet Coke Plus complies with FDA's policies and regulations."

Coke launched Diet Coke Plus in March 2007 as a calorie-free soft drink and "a good source of vitamins B3, B6, and B12, and the minerals zinc and magnesium," according to a press release. The drink hasn't been a huge hit, however, selling the equivalent of 10.2 million 8-ounce cases in 2007, compared with 990 million 8-ounce cases of Diet Coke that year, according to Beverage Digest, an industry publication and data service.