Producer of two popular brands of green tea drinks have been warned by the Food and Drug Administration about making nutrient claims that are unauthorized.

The FDA in a warning letter to Dr Pepper Snapple Group said that it is improper to state that the company's Canada Dry Sparkling Green Tea Ginger Ale is enhanced with antioxidants.

This was because the drink was a carbonated beverage and was a snack food. The FDA said that the beverage should not claim to be nutritionally fortified.

The letter added that nutrients that claim to contain antioxidants are not recognised to contain antioxidants activity.

The FDA also stated that claims were being made by Unilever Inc.'s Lipton Green Tea 100 per cent Naturally Decaffeinated about being healthy for those who have a risk of heart diseases.

FDA told Unilever that these claims mean that Lipton green tea must prove its effectiveness and safety standards before making such claims.

FDA added that these claims were also against federal wording rules.

A spokesman for Plano, Texas-based Dr Pepper Snapple Group said, “The company was looking forward to working with the FDA and addressing the issues raised."