A new study has found that drizzling a small amount of extra virgin olive oil over vegetables before cooking can significantly boost their nutritional value while also making them taste better. Researchers determined that even a modest quantity of this popular kitchen staple added to vegetable patties raises levels of heart-healthy monounsaturated fats and certain antioxidants. The findings, reported by Food & Wine, add to a growing body of evidence supporting the everyday use of extra virgin olive oil in home cooking.
The study was published in January in the journal Foods by scientists at the University of Chile, who examined the nutritional impact of incorporating a small amount of extra virgin olive oil into vegetable patties. The research team prepared 42 patties made from broccoli, carrots, onion, egg whites, oats, and a spice blend that included salt, pepper, garlic powder, and cumin. They divided the recipes into two groups, one containing half a teaspoon of extra virgin olive oil and one without, and then cooked each group using three different methods.
The three cooking methods tested were oven roasting at 356°F for 15 minutes, air frying at 356°F for 15 minutes, and deep frying at 338°F for two minutes. Before and after cooking, the team measured the nutritional profiles of each patty, tracking fat, protein, carbohydrate, and mineral content alongside antioxidant levels. The results showed a clear difference depending on both the cooking method and whether olive oil was included.
Deep frying turned out to be the least favorable option for anyone watching their saturated fat intake, with that method increasing total fat content by as much as 75% compared to oven-roasted or air-fried versions. Oven roasting and air frying, on the other hand, kept oil absorption relatively low, suggesting that how you cook your vegetables may matter just as much as what you put in them. That said, the deep-fried patties made with extra virgin olive oil actually showed the highest total polyphenol content, which highlights the antioxidant benefits of olive oil even under more intense cooking conditions.
Patties that contained extra virgin olive oil consistently showed higher levels of monounsaturated fats, particularly oleic acid, a fatty acid found naturally in olive oil that is linked to improved heart health and anti-inflammatory effects. The study also recorded other changes in fatty acid composition, including increases in palmitic and alpha-linolenic acid during deep frying, as well as a reduction in polyunsaturated fatty acids like linoleic acid in the olive oil-enriched patties. Raw patties generally had the highest antioxidant counts overall, which suggests that heat can degrade certain compounds, though those made with olive oil retained more antioxidants after cooking than those without it.
The researchers did not stop at nutritional analysis. They recruited 53 volunteers to taste and rate the patties on appearance, aroma, flavor, and texture. The results were decisive: the oven-roasted and air-fried patties made with olive oil came out on top, with nearly nine out of ten participants preferring the air-fried olive oil version and more than three-quarters favoring the oven-roasted one.
The findings likely extend well beyond vegetable patties. Because many vitamins and antioxidants found in vegetables are fat-soluble rather than water-soluble, adding a small amount of oil during cooking can help the body absorb those nutrients more efficiently. Tossing broccoli, carrots, Brussels sprouts, or sweet potatoes with a little olive oil before roasting, for instance, may help with the absorption of fat-soluble vitamins and carotenoids. The researchers suggest that even a modest amount, roughly half to one teaspoon per serving, may be enough to make a meaningful difference.
This is not the only recent study pointing in the same direction. A separate study published in December in the journal Food Nutrition investigated how extra virgin olive oil can help the body extract more key nutrients from kale. As those researchers explained, while kale is packed with nutrients, the human body struggles to absorb some of its most important vitamins, including A, D, E, and K, because they dissolve in fat rather than water. When kale was dressed with a special oil-and-water-based sauce described as a “nanoemulsion-based sauce,” the researchers’ digestion model absorbed significantly more vitamins and antioxidants from both raw and cooked kale.
Extra virgin olive oil is one of the cornerstones of the Mediterranean diet, which is widely recognized by nutrition researchers as one of the healthiest dietary patterns in the world. It is produced by cold-pressing whole olives and is distinguished from refined olive oils by its higher polyphenol content, which are natural plant compounds with powerful antioxidant properties. Oleic acid, the predominant fatty acid in extra virgin olive oil, typically makes up between 55% and 83% of its total fat content, and numerous large-scale studies have associated regular consumption of olive oil with reduced risk of cardiovascular disease, type 2 diabetes, and certain cancers. The polyphenols in extra virgin olive oil, including oleocanthal and oleuropein, have also been studied for their potential anti-inflammatory and neuroprotective effects.
If you have thoughts on how you use olive oil in your everyday cooking or whether these findings change how you approach meal prep, share them in the comments.
