Federal health regulators have scolded Coca-Cola for placing inappropriate nutritional claims on its Diet Coke Plus soft drink, according to the Associated Press. The Food and Drug Administration issued a warning letter to Coca-Cola, objecting to the product''s labeling, which describes the drink as "Diet Coke with Vitamins and Minerals." Regulators said the beverage does not have enough nutrients to justify the use of the word "plus" in its name. According to the agency, foods labeled "plus" must have at least 10 percent more nutrients than comparable products. Additionally, the FDA said it is inappropriate to add extra nutrients to "snack foods such as carbonated beverages." In the letter, the FDA calls on Coca-Cola to revise the drink''s labeling and inform the agency of its plans within 15 days of receiving the message. The FDA has posted the letter online. Coca-Cola said it will respond to the FDA, but currently has no plans to change the label. The company launched Diet Coke Plus in March 2007, touting it as a calorie-free soft drink with extra vitamins and minerals. According to the company''s Web site, the drink contains vitamin B, zinc and magnesium. Once a niche market, nutrient-enriched beverages have grown into multibillion dollar business, which includes everything from calcium-enhanced orange juice to energy drinks containing ginseng, ginkgo and other herbs. In recent years the FDA has begun cracking down on companies that overstate the benefits of the products. The FDA has endorsed health claims on several foods, but only after government researchers verified that the products help prevent disease. Oatmeal products, for example, can carry the FDA-approved claim, "may reduce risk of heart disease." The FDA regularly issues warning letters to companies that do not follow regulations for manufacturing and marketing. The letters are not legally binding, but the agency can take companies to court if they are ignored.