Acids found in food and beverages can have a harmful affect on your teeth. Each tooth has a hard protective layer called the enamel. When acidic foods come in contact with this enamel, they can make it soft. When this happens repeatedly, your enamel can wear away and can never be restored naturally.
You can also get more cavities if you regularly eat foods with high acidity. It's impossible to make a complete list, as acidic foods are found everywhere, but following are some of the more common acidic foods and beverages: Beer, Beef, Soft drinks, Coffee, Fish, Lamb, Pasta, White Flour, Table Salt, Pork and White Bread. Even grazing on fruits and vegetables slowly throughout the day can expose your teeth to acid damage.
Bacteria in your mouth, which feeds on sugars, can also create acid. The best way to avoid acid damage is to avoid snacking continuously throughout the day. Rinsing and flossing, and chewing sugar free gum is also helpful. Brushing right after eating acidic foods though, can actually damage the teeth, because the enamel is soft from the acid. If you want to balance the acidity in your mouth....eat more nuts and dairy products.