There is lots of controversy about flavorings for e-cigarettes. Here are some of the plant extract flavorings for e-cigarettes. Lung damage has been associated with vaping with e-cigarettes with flavorings found to be particularly harmful. Polyphenols bind iron. Polyphenols binding iron, which is needed for hemoglobin, in the lungs could adversely affect the ability to breathe. Mint flavorings are getting a pass in the FDA regulations on e-cigarette flavorings, however, mint has very high polyphenol contents.