Researchers at the University of Dundee have discovered that different methods of cooking vegetables can vary their effects on dental erosion. A new study led by Dr Graham Chadwick from the School of Dentistry, found that oven-roasted ratatouille was significantly more acidic than the traditional stewed version of the dish (Chadwick R G. Eur J Prosthodont Restor Dent 2006; 14: 28–31).

The research was based on reports that a vegetarian diet may give more risk of dental erosion due to the acidic nature of a large number foods involved, including fruit and vegetables. Ratatouille is a popular vegetarian dish made from tomatoes, onions, aubergines, courgettes and red and green peppers, and can be either stewed on a stove-top or oven roasted. The team looked to see whether the cooking method had any effect on its final acidity and therefore its potential for contributing to dental erosion.

Although ratatouille is always acidic, oven roasting was found to increase the acidity of the dish to the point where it was equivalent to some carbonated drinks. 'The finding that cooking method has an impact on the acidity of food is an interesting and useful tool for dentists when advising patients on ways to reduce their chances of dental erosion,' said Dr Chadwick.

The Dundee team also looked at whether the cooking method had an impact on individual vegetables and fruits. They found that there was no effect on the acidity of tomatoes or onions, but roasting resulted in more acidic aubergines, green peppers and courgettes. Red peppers were found to be more acidic when stewed.