Many of us believe that boiled vegetables are more nutritious and healthier than stir-fried vegetables. However, a study has reached the opposite conclusion.
This research, conducted by the University of Granada (Spain), was published in the journal Food Chemistry. According to the researchers, stir-fried vegetables are healthier than boiled ones, especially when we use olive oil for stir-frying.
Why Are Stir-Fried Vegetables Healthier?
Professor Cristina Samaniego Sánchez, one of the authors of the study, explains: “Stir-frying vegetables not only helps preserve the phenolic compounds in the vegetables but also adds additional phenolic compounds from the oil to the dish. Phenolic compounds are plant compounds that have been proven to protect cells and prevent various diseases.” In contrast, boiling vegetables does not increase the phenolic compound content as stir-frying does.
Moreover, stir-frying retains more nutrients than boiling. A previous study published in the journal Food Science showed that boiling celery causes a loss of 14% of the antioxidants present in the vegetable. Antioxidants can help prevent the formation of cancer cells in the body.
Another study published in the journal Food and Chemical Toxicology measured glucosinolates—a nutrient with anti-cancer properties—in broccoli, Brussels sprouts, cauliflower, and cabbage after boiling. The results showed that boiling reduced the glucosinolate content in broccoli by 77% and in cauliflower by 75%. The scientists found that 90% of the glucosinolate loss was dissolved in the water used to boil these vegetables.
How to Eat Stir-Fried Vegetables for Better Health?
Stir-fry vegetables with healthy oils (Illustrative photo)
Stir-frying vegetables not only preserves the nutrients but also enhances the levels of beneficial plant compounds. However, when stir-frying, it is important to use healthy cooking oils.
Researchers in Spain found that in the Mediterranean diet—a diet praised for its many health benefits—people often consume stir-fried vegetable dishes along with nuts and olive oil. The researchers also compared the nutritional content when stir-frying broccoli with various oils, including refined olive oil, extra virgin olive oil, peanut oil, soybean oil, and canola oil. The results showed that stir-frying with extra virgin olive oil retains the most nutrients.
However, when consuming stir-fried vegetables, one should be aware that this cooking method can increase the calorie content of the dish. Therefore, it is advisable to eat in moderation to avoid excess calorie intake.
Overall, according to information from the Blue Zones website, (a science group that studies the lifestyles of the longest-living people in the world), boiling vegetables may not be the best way to retain nutrients. However, to maximize the nutritional benefits from vegetables, in addition to stir-frying, you can also stew or make soups as they allow you to eat both the water and the vegetables. Steaming is also a very effective method for preserving nutrients, antioxidants, and the flavor of vegetables.
