Does Roasting Vegetables Ruin Nutrients? - Sharon Palmer, The Plant Powered Dietitian (2024)

Everybody loves roasted vegetables, right? But does roasting veggies, from air fryer roasted vegetables to sheet pan roasted vegetables, ruin their nutritional value? Learn all about this hot topic here.

Delicious, golden brown, roasted veggies are as hot as ever! The art of roasting fresh veggies, such as asparagus, cauliflower, and brussels sprouts, on a pan over high heat with a touch of olive oil and seasonings makes them taste simply divine. Whether it’s sheet pan roasted vegetables, air fryer roasted vegetables, or even roasting frozen vegetables, the result is pure genius. The carbohydrates in the veggies caramelize, mellowing out strong flavors into golden, toasty perfection—all with a nice pleasant crunch. What’s not to like? In particular, roasted root vegetables, such as parsnips, carrots, sweet potatoes, and turnips result in an amazing textures and flavors. You can serve roasted veggies as a side-dish, and in salads, kebabs, grain bowls, pasta, sandwiches, wraps, pita, and the list goes on. Some of my favorite roasted veggie recipes include the following:

• Sesame Soy Glazed Roasted Japanese Sweet Potatoes
• Roasted Sesame Shish*to Peppers
• Roasted Winter Vegetables with Za’atar
• Mediterranean Sheet Pan Veggies
• Roasted Butternut Squash with Dates Figs and Pistachios
• Roasted Romanesco Cauliflower with Raisins and Pine Nuts

But does roasting vegetables ruin nutrients? Today, I’m answering your top questions on whether roasting veggies ruins nutrients.

Question: I love roasted vegetables, but does roasting them at high heat destroy their nutrients?

Answer:

No, you don’t need to forgo roasted veggies because of high heat. The fact is that all forms of cooking can destroy some of the nutrients (such as vitamin C and B vitamins) in vegetables. But the flip side is that some nutrients actually become more bioavailable when vegetables are cooked, since cooking helps release the nutrients from the cell walls of the plant. These include nutrients in the carotenoid family, such as lycopene (found in tomatoes and red peppers) and beta-carotene (in carrots, spinach and kale). Mushrooms, asparagus and cabbage supply more antioxidant compounds when cooked compared with raw. And antioxidant compounds in foods we eat may help protect against cancer and other diseases.

One caveat: Charring can cause the formation of acrylamides (potential cancer-causing chemicals), particularly in starchy foods such as potatoes. Instead, roast your starchy veggies to a golden brown. Meanwhile, some nutrients, such as vitamin B-6 and folate in broccoli and the polyphenols (micronutrients that help protect against cancer and cardiovascular disease) in onions are better preserved in raw fruits and vegetables. So, it’s good to enjoy a diet that has some raw and some cooked foods to gain the benefits of each. If you like roasted vegetables, continue to enjoy them. Steaming, microwaving and boiling vegetables are also fine methods, but minimize the water you use and length of time you cook them to preserve nutrients. Try to avoid frying them to keep calorie levels in check and reduce overall nutrient loss.

Here are more roasted veggie recipes to enjoy:

Roasted Kohlrabi with Pumpkin Seeds
Maple and Balsamic Roasted Brussels Sprouts
Roasted Rosemary Potatoes and Tomatoes
Roasted Chicory with Pistachios and Pomegranates
Sheet Pan Roasted Vegetables and Beans with Za’atar

Another good way to enjoy veggies is to grill them. Check out this step-by-step guide for grilling vegetables here.

Check out the other nutrition questions I’m answering at The Plant-Powered Dietitian:

• Why Do Beans Cause Gas?
• What to Put in a Salad To Make it Healthy?
• How Do I Get Vegan Calcium Sources?
• What are Common Nutrition Issues for Plant-Based Diets?
• What are the Best Supplements for a Vegan Diet?
• Are There Benefits for the AIP Diet?

About Ask Sharon:

As part of my program “Ask Sharon”, I am answering the top question of the month submitted through my blog, Facebook, Twitter or Instagram to answer here. You can even win a prize! Don’t forget to submit your burning nutrition question this month via my blog, or other social media.

Main image: Roasted Sesame Broccolini from California Vegan, published in 2021.

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