Ratatouille can rot your teeth
Cooked vegetables can be as acidic as tooth-eroding fizzy drinks, scientists warn.
Eggplants, green capsicum and zucchini become more acidic when roasted in the oven, while red capsicum becomes heavily acidic when stewed, according to a study at Scotland's University of Dundee.
But the acidity of onions or tomatoes does not change with the cooking method.
Dr Graham Chadwick publishes his findings in the current issue of the European Journal of Prosthodontics and Restorative Dentistry.
The researchers study was prompted by reports that people on a vegetarian diet may be at risk of dental erosion. This is because the large quantity of foods that they eat, such as fruit and vegetables, tend to be quite acidic.
So the researchers studied how different methods of cooking a vegetarian dish like ratatouille could affect its acidity.
Ratatouille was acidic no matter how it was cooked, but oven-roasting significantly increased the acidity of the dish, compared with stewing.
"The acidity of ratatouille prepared by oven-roasting is the same as that of some carbonated drinks that, when consumed in excess, are believed to contribute to the development of dental erosion," says Chadwick.
Acid can etch into the thin layer of enamel that protects the teeth and can also affect the underlying dentin.
Earlier this year, researchers presented research into the corrosive potential of acidic drinks at the American Association for Dental Research annual meeting in Florida.
The University of Iowa researchers found that drinks including fizzy drinks and apple juice can erode exposed root surfaces.