Burger King has reintroduced, in a small number of its restaurants, some of the food colors that have been associated with possible hyperactivity in young children, according to the UK Food Standards Agency (FSA).

The company has reintroduced the colours as a result of trialling the Coca-Cola Freestyle drinks dispensing system for six months. The trial ends in December 2012.

The Agency noted that Burger King will therefore be removed from its list of caterers and restaurants whose food/products is/are free from these colors.

The vending machine allows users to choose from a variety of different flavours, but for technical reasons, Coca-Cola said it was unable to remove all of the colors associated with possible hyperactivity from the drinks system before the trial.

However, Coca-Cola reaffirmed its commitment to remove these colors from its entire product range, the agency said.

Six food colors that have been associated with possible hyperactivity in young children have been identified by the agency. They are sunset yellow FCF, quinoline yellow, carmoisine, allura red, tartrazine, and ponceau 4R .

The Agency is encouraging the food industry to voluntarily remove these colors from their products.