Traditional culinary view maintains that eating raw vegetables is more nutritious than eating cooked ones, but a small and growing number of studies suggest that cooking may actually increase the release of some nutrients, according to study leader Nicoletta Pellegrini, of the University of Parma in Italy.
However, she added that scientists are seeking more complete data on the nutritional properties of cooked vegetables.
For the study, Pellegrini and colleagues evaluated the effects of three commonly-used Italian cooking practices – boiling, steaming, and frying, on the nutritional content of carrots, zucchini and broccoli.
Researchers found that boiling and steaming maintained the antioxidant compounds of the vegetables but frying caused a significantly higher loss of antioxidants in comparison to the water-based cooking methods.
For broccoli, steaming actually increased its content of glucosinolates, a group of plant compounds touted for their cancer-fighting abilities, they discovered.
The research team said that their findings suggest that it may be possible to select a cooking method for each vegetable that can best preserve or improve its nutritional quality.
The study is published in the Journal of Agricultural and Food Chemistry.