QUESTION: “Hey Dr. Neal, thank you for sharing all this information which has helped me to live a healthier life. I just listened to Episode 1323 (on freezing fruits and vegetables) and it got me wondering. I often use the air fryer to cook frozen vegetables. Is that saving some nutrients or is it still best to boil them in water?”
Listen to Dr. Neal narrate this post on Episode 1393 of the podcast Optimal Health Daily.
DR. NEAL: Thank you so much for your question. I’m so glad you find the show helpful and thank you so much for your kind words.
I wasn’t sure whether an air fryer would catch on. It wasn’t until the last holiday season that I realized air fryers were a real phenomenon. Multiple family members listed an air fryer on their holiday wish lists. Since then, I’ve heard numerous stories of people using their air fryers for cooking EVERYTHING… from the usual French fries and mozzarella sticks to vegetables, as you mentioned, and even cooking up chicken from scratch.
So, are there any health benefits to using an air fryer as your main cooking appliance? The bottom line: it depends.
What’s an Air Fryer?
Before I get into that, I need to describe what an air fryer is and what it does. The product is designed to be a healthier alternative to deep frying.
Instead of submerging food in oil and cooking it that way, an air fryer works by circulating hot air around the food which cooks it (kind of like a convection oven). In case you’re wondering, this hot air is around 400 degrees Fahrenheit (or, around 204 degrees Centigrade).
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You can brush some oil on the food, but you don’t have to. Either way, this hot air will cook the outside of the food first while keeping the inside moist. There’s a basket at the bottom to catch any grease that drips off. But in the end, the air fryer is designed to provide a similar texture and flavor to deep fried foods. But since oil is optional, you don’t get that extra fat and calories.
So, if watching calories and total fat is important, then yes, an air fryer would be healthier. But what about preserving nutrients?
Does an Air Fryer Preserve Nutrients?
Unfortunately, when it comes to actual research on air fryers there isn’t a whole lot out there… yet. I imagine that we’ll see more published studies as time goes on. So, as I answer your question Sarah, please know that this is based on my best guess at this point.
Based on previously published research looking at nutrient preservation when cooking vegetables, we find that high heat usually leads to a loss of nutrients, especially antioxidants. So, when cooking vegetables at 400 degrees Fahrenheit (or 204 degrees Centigrade) as you would in an air fryer, it’s basically a given that nutrients will be lost. But I would guess that the amount of nutrients lost would be the same as if you roasted them in the oven. But if you were to cook vegetables in water or in the oven using a roasting pan, you might be able to recapture some of those lost nutrients.
This is because when heated, some of the nutrients start to leave the vegetables and get into the surrounding liquid.
I’ll give you an example: say you’re cooking some organically grown frozen broccoli in boiling water. After the broccoli has finished cooking, I would save the water you just used to cook the broccoli and repurpose it somehow. You could use the leftover water to make a soup or stew. You could use it to boil your pasta. This is because some of those lost nutrients that leached out of the broccoli likely ended up in the boiling water. If you’re roasting vegetables in the oven and using a roasting pan, save those pan drippings and add them to another dish or drizzle it on top of the vegetables.
The Bottom Line
So, my best guess based on previously published research is that air frying frozen vegetables will probably lead to a loss of a decent amount of nutrients, particularly antioxidants. That doesn’t mean that using an air fryer to cook frozen vegetables is completely off limits. It just reminds us that consuming a variety of vegetables using a variety of cooking methods (raw, boiled, roasted, and yes, even air fried) would be most beneficial for our health.
Listen to Dr. Neal narrate this post on kids and healthy food on Episode 1386 of the podcast Optimal Health Daily.
