Mountain Dew is a lemon-lime soda with a food ingredient in the Institute of Medicine (U.S.) Food Forum recipe that is banned in many countries across Europe and Japan.
The soda versions manufactured by PepsiCo contain the food additive Brominated Vegetable Oil. Such vegetable oils are also popular with the name "Brominated Flame Retardants."
This soda is controversial due to the ingredient Bromine, which has been linked to varying health conditions. However, you can find versions of this soda across Europe without this toxic chemical.