Dave Parker
A study shows whether roasting vegetables is healthy depends on the precise method of preparation. If you keep one thing in mind, fried vegetables are even healthier than boiled ones.
One factor that makes vegetables so healthy is their wealth of so-called phenols: the secondary plant substances have an antioxidant effect, i.e. they protect the cells from damage and thus help to prevent diseases such as cancer or diabetes, and heart disease. But does it matter how the vegetables are prepared? In a study, Spanish and Mexican researchers examined whether roasting vegetables is healthy or whether broccoli and the like should be boiled to achieve the greatest possible health effect.
Study: Boil or fry vegetables?
The research team led by Prof. Cristina Samaniego Sánchez at the University of Granada (Spain), together with colleagues from the University of Sur Jalisco (Mexico), investigated which type of preparation preserves the phenols better in the vegetables – boiling or roasting. The scientists prepared different types of vegetables (potatoes, squash, tomatoes, and eggplant) in different ways. They fried the vegetables in extra virgin olive oil and boiled them in water, or a mixture of water and olive oil. The researchers then analyzed, among other things, the content of fat and phenols in the vegetables and compared them with that of raw vegetables.
Can you fry it with olive oil?
You can use olive oil for frying. Virgin olive oil can be heated up to around 160 °C – ideal for frying fish and vegetables. Steaks prefer it hotter (approx. 200 °C). Refined olive oil is well suited for this (the oil is refined if it is not expressly labeled as virgin or cold-pressed).
Are Roasted Vegetables Healthy? Yes, on one condition
The result: Frying in olive oil increased the phenol content in the vegetables – this effect could not be achieved when cooking. Prof. Samaniego: “Oil as a means of transporting heat increases the number of phenols in vegetables, in contrast to other methods of preparation such as cooking, where the heat is transported through the water.” This means that larger amounts of the plant substances are retained during frying and the oil enriches the vegetables with added phenols. As a condition, the researchers call the use of extra virgin olive oil.
Although roasting also increases the fat and calorie content in the vegetables, the study leaders say that the vegetables are still healthier overall.
