I came across an article the other day extolling the benefits of frying vegetables in olive oil. The article proclaimed that frying the vegetables was actually healthier than boiling or sautéing them.
Why were the fried vegetable purported to be healthier than the other preparations? Because they had higher polyphenol content (a type of antioxidant) than the vegetables prepared using the other methods. While I don’t dispute the findings (although the full article is behind a paywall so I can’t state that for certain and I do wonder where the funding came from) I do think that the comparison is disingenuous.
All vegetables were cooked for the same amount of time, regardless of preparation method. In reality, it would take differing amounts of time to cook these vegetables using different cooking techniques.
I also question the cooking methods selected. Why not roasting or steaming? We know that high nutrient losses are going to occur with boiling and at high temperatures as water soluble and heat sensitive vitamins are leeched from the veggies or destroyed.
The selection of vegetables is also curious to me. They used eggplant, tomato, pumpkin, and potato. Would it be because these types of vegetables would readily absorb oil that they were chosen? I’d be curious to see what the results would show if vegetables such as asparagus, broccoli, cauliflower, or snap peas were used.
While an increase in polyphenols may be seen when these vegetables are fried, this doesn’t necessarily mean that we should all start frying our vegetables. Frying increases acrylamide in food which is a potential cause of cancer. It’s doubtful that the increased polyphenol content from the olive oil justifies the increased acrylamide content.
Steaming vegetables until tender crisp is one of the best methods for preserving nutrients. If you want to increase the polyphenol content and maximize nutrition, why not toss your steamed vegetables with a little olive oil?
Have some raw vegetables, some roasted, some sautéed, some steamed, maybe some boiled or fried. Variety is an important factor in a healthy diet. That encompasses not just the foods we eat but how we prepare them.