A dentist from Beverly Hills, Calif. claims that a bitter power found in dark chocolate, theobromine, can actually harden the enamel. This would add protection to the teeth against the possible impact of staining.
Milk chocolate, however, would not have the same effect based on its high sugar content that causes bacteria and bad breath.
Dr. Harold Katz also states that cheese, green tea and strawberries have a beneficial impact when it comes to whitening teeth. The foods, just like dark chocolate, produce the best results when consumed early in the day after plaque piled up over night.
Strawberries can be mashed into a paste and baking soda to create a natural whitening solution. This, however, doesn’t work for all berries as some actually stain teeth. It’s the malic acid in strawberries that does the trick.
Green tea helps because it possesses tannins and polyphenols that stop bacteria and plaque from adhering to the surface of the tooth.