Acid is known to damage your teeth.

In fact, acid starts to weaken enamel at a pH (acid scale) below 5.5. Many of the food we eat and drinks we drink have a pH lower than that. Here's a sample of the pH of some common foods and drinks

Water                pH 7
Avocado            pH 6.5
Banana              pH 4.5-5.2
Beer                   pH 4.0-5.0
Salad Dressing  pH 3.5-4.2
Orange Juice     pH 3.4-3.8
Cola                   pH 2.4
Energy Drinks   pH 2.4-3.6
Wine                  pH 2.3-3.8
Lemon Juice      pH 2.2


Beware of the acidity of your food, make sure to drink some water after consuming something acidic, that way you can reduce the acidity in your mouth and the damage to your teeth!