The Food and Drug Administration (FDA) has warned the Coca-Cola Company that its label for Diet Coke Plus is misleading. At issue, the agency says, are the label's nutritional claims.

In a warning letter to Coke's CEO Muhtar Kent, the FDA said it has reviewed the label and has concluded the product is in violation of the Federal Food, Drug and Cosmetic Act. It has further found the product is "misbranded," because it makes a nutrient content claim but does not meet the criteria to make the claim.

The FDA says Diet Coke Plus bears the term "Plus" as part of its name, and the principal display panel of the product label also includes the language, "Diet Coke with Vitamins & Minerals." The ingredient list includes the following added vitamins and minerals: magnesium sulfate (declared at 10% of the Daily Value (DV) for magnesium in the Nutrition Facts panel), zinc gluconate (declared at 10% of the DV for zinc), niacinamide (declared at 15% of the DV for niacin), pyridoxine hydrochloride (declared at 15% of the DV for vitamin B6), and cyanocobalamine (declared at 15% of the DV for vitamin B12).

"The term 'plus' in Diet Coke Plus, read in conjunction with the language Diet Coke with Vitamins & Minerals, meets the definition of a nutrient content claim because it characterizes the product's level of vitamins and minerals, which are nutrients of the type required to be in nutrition labeling," the FDA said. "Based on our review, we have concluded that this product is in violation of the Federal Food, Drug, and Cosmetic Act."

The FDA said it does not consider it appropriate to fortify snack foods such as carbonated beverages, with vitamins and minerals, and then to try and promote the snack food's nutritional value.

"It is your responsibility to ensure that all of your products are in compliance with the laws and regulations enforced by FDA," the agency warned. "You should take prompt action to correct the violations. Failure to promptly correct these violations may result in regulatory actions without further notice, such as seizure and/or injunction."