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Follow-Up: How to Cook Vegetables, Simplified

By , SparkPeople Blogger
Last week, I blogged about How Cooking Affects Your Vegetables' Nutritional Value. We learned that adding a bit of fat helps you absorb more phytonutrients from your vegetables and that microwaving and steaming retain more of the nutrition than boiling or frying.

Afterwards, many of you had questions, good ones:

"Like several people mentioned, I love roasted veggies. But how does that impact nutritional value?? Does anyone know?"
"What about soup? I know the veggies are boiled more or less but everything is still in the pot. Is soup a bad process for keeping the nutrients of veggies?"

As I'm not a nutritionist, I headed straight to the source. I contacted the Journal of Food Science, which had published the original study.
I was sent the full study, which cleared up many of our questions.

The study examined the effects of boiling (in a quart of water), microwaving (in a glass dish with no added water), pressure-cooking (with about 1 1/2 c water), griddling (cooking in a skillet with no fat or oil), frying (cooking in a skillet with about a half-cup of olive oil), and baking (in a ceramic container at 400 degrees F with no fat or oil) on a pound each of 20 vegetables. Scientists measured the antioxidant level of each vegetable after cooking.

Some interesting findings:

  • Artichokes were the only vegetable to retain very high amounts of nutrients regardless of cooking method.

  • The highest losses were observed in cauliflower after boiling and microwaving, peas after boiling, and zucchini after boiling and frying.

  • Beets, green beans and garlic kept all antioxidant activity after most cooking treatments.

  • Swiss chard and peppers lost significant antioxidant activity in all processes.

  • Celery actually increased the amount of antioxidants after every cooking method except boiling.

The conclusion: "Water is not the cook's best friend when it comes to preparing vegetables." However, the study did recommend further research on cooking's impact on nutrition.

The findings reiterate what we've probably all observed in the kitchen.
If you boil or pressure cook vegetables, they break down, they change color and they become softer. We're taught that the vibrant color of vegetables is the key to their nutritional significance; if we cook them for too long, they become lackluster and dull. That brilliant, nutritious goodness inside of them, while unlocked in most cases by brief, dry cooking methods, is leached out if they're cooked for too long or in too much water.

And we've all witnessed the effects of overcooked vegetables. If you boil green beans for an hour, they turn brown and the cooking water takes on a greenish-brown tint as the nutrients--not to mention the flavor--leaves the vegetables.

In soup, we're again cooking vegetables for long periods of time, but we're consuming the water in which they've been cooked. While some nutrients might be lost (and that varies based on cooking time and vegetable), you're still consuming the nutrients as long as you eat the broth.

Roasting vegetables is a great way to transform vegetable haters into vegetable lovers. Roasting (with a bit of heart-healthy fat like olive oil) and baking (without oil) remove some of the water from a vegetable, concentrating and enhancing the flavor of the food's natural sweetness. The starch in potatoes is tamed into a smooth and creamy texture, the sharp flavor of turnips is rendered sweet and the distinct tang of radishes is tamed by the oven.

In recent years, many people have heard that grilling or broiling have been linked to cancer. To clarify: The protein in meat, poultry and fish contains substances that, when heated at high temperatures, form carcinogenic compounds called heterocyclic amines (HCAs). Vegetables do not contain these substances. (And the American Institute for Cancer Research encourages consumers to focus more on what they're eating, not how it's cooked. In other words, moderate your meat intake and choose lean cuts, the group says.)

Grilling vegetables could probably be likened to griddling or baking, meaning that it is a pretty good way to retain nutrients. Just don't scorch them--if vegetables are burned, it's a pretty good bet you're not maximizing their nutritional value.

The better cooking methods: microwaving, griddling (sautéing in a nonstick pan with no oil) and baking (roasting). Frying is in the middle (in terms of retaining nutrients--added fat wasn't taken into consideration in this study). The least preferable methods: boiling and pressure cooking. If you don't have a microwave (like me), then you can steam vegetables on the stove with minimal water and achieve an effect similar to microwaving.

When you're cooking your vegetables, remember to use as little water as possible, choose the microwave or a steamer, and add (minimal heart-healthy) fat. And really, don't stress too much about how you're cooking them, just make sure you're getting at least five servings of vegetables (and fruit) each day!

I hope this cleared up any confusion!

How do you cook your vegetables? Have any foolproof recipes to share?

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GETULLY 11/20/2020
Roasting all the way! Report
DEE107 7/29/2020
thanks Report
KOALA_BEAR 3/21/2020
Since pressure cooking kills nutrients, glad I didn't give in & buy an instapot. Keeping my microwave & crockpot.
Thanks Report
Thank you Report
thanks Report
I need to explore more veggies and how to cook them. Report
Thanks for a great article. Report
great article Report
Great article. Cant wait to try different methods other than steaming. Report
I like to use the steam bags for the microwave. The foods cooks quickly and tastes great Report
Thanks for following up with the different ways on how to cook vegetables. I am a picky eater when it comes to vegetables, so I am trying to find different ways of cooking them. Glad to find boiling doesn't affect the artichoke's nutrients, because I think a boiled artichoke tastes more delicious than when it's microwaved! Report
I mostly roast my veggies. I used to steam them only but roasting imparts so much more flavor! I made mashed potatoes last week & added pureed cauliflower to them & no one could tell. Report
Great article..thank you so very much Report
Great series. You're probably going to lose a couple of vitamins in soup even if you eat the broth, like Vit C and B5 (pantothenic acid) because they are heat labile: they actually break down. But they are readily available in many vegetables and fruits, so it's enough to eat some raw fruits and vegetabes to get enough. Report
I have known for a long time North Americans overcook their veggies, which is why I choose to eat everything raw. But if I had to eat cooked, the Asian way of a quick saute in a Wok is best, then your broccoli turns a brilliant hue of green but retains crispness, as does the carrots and everything else. And its so fast to boot! Report
really good to know - I always worry about what good I'm really doing by cooking my veggies - good to know the ways I can make sure the most "good stuff" stays in there. Report
I love my vegetables in salads. I have even tried the recipe above. Very Good. Report
Ha! One of my top favorite veggies is artichokes. Birdseye has frozen artichoke hearts, I sautee with garlic, cayenne pepper and olive oil. I like fresh artichokes steamed. Report
Good stuff! Report
This is very helpful in thinking about how best to cook. I am learning to love the different tastes of healthy foods! Report
I have a question: The new SP chef has a video teaching us how to burn tomatoes and peppers and peel the skin. How does that effect the nutritional value of the tomato and the peppers?

Califartist, there is a great SP recipe for eggplant parmesan that you bake and no oil is needed. It may be called Lowfat Eggplant Parmesan. It's very good.

It's nice to know celery increases its antioxidant level. Who would've thought that was possible? That would be a good quiz question. I cook vegetables in a variety of ways, steaming, sauteing, in soup, in risotto, microwaving, etc.

It's probably good that I also eat them raw! Report
Thanks for the follow up, I enjoyed this article. I like my veggies grilled, roasted, steamed or very lightly "stir fried" . Report
I want to learn some good ways to cook eggplant that don't soak up the olive oil. We've barbequed them with a light brush of EVOO, but I still worry about the extra calories in that. Suggetions? Report
I have come to love veggies:
In the summer I grill them and in the winter I roast them and make tons of different kinds of soups. Report
I love fresh veggies with a little olive oil cooked on the grill. Report
Stepf, I'm an avowed "veg-head," and you are most definitely my go-to gal for info on Ma Nature's finest, having penned a marvelous article on roasted veggies, too. When not roasted, veggies are pretty fabulous steamed, so I was delighted to hear that my fave veg in the universe, the artichoke, can be cooked any ol' way to retain its goodies! Steam one of the huge globe arties for two hours and use Promise fat-free margarine blended with fresh crushed garlic for a fat-free, luscious dip. The secret is to microwave, say, about 4 T. of the Promise for just the slightest amount of time on 50% power, just 'til the edges start to liquify; then stir again. WOW!!

Your devoted fan, Susan Report
I steam them. Report
I have never really liked veggies, but last year I found a little bit of olive oil and grilling them does taste pretty good for most of the vegetables that I have tried. Some of the spice blends lightly sprinkled on are good to mix up the flavours a bit Report

That looks really good! Great now I am hungry:) Report
Thanks for the clarification. I love to roast a whole lot of veggies then refrigerate so I can add to a salad or just nosh on them when the hunger pangs...or is it pains :) hit. Report
Mmmm...I love roasted vegetables. Report
Good info on which way is best to cook veggies Report
my veggies are steamed or raw. I don't have any "recipes" as I like my veggies plain. Report
I usually steam my vegetables. A lot of times I will start my potatoes in the microwave while the water is getting hot and then finish them off in the steamer. Report
YOU, turned me into a roasted veggie freak, Stepf, hahahahaha!! and I can't THANK YOU enough for all your BRILLIANT recipes, and the food research you 'do' for us every chance you get!! I am sooo excited to find out what YOU'VE been up to... what NEW 'thing' you've found to share with us!! hehe!! Just want you to KNOW how much I appreciate you today!!
Have a HEALTHY weekend, everyone!!
¸.·´¸.·*´¨) ¸.·*¨)
(¸.·´ (¸.·´ *Annie
Oh... I did not KNOW that about Artichokes & Celery!! VERY cool!! Report
I eat most of my vegetable raw. When I cook them, I steam or grill them. Report
Great info - in simple terms - thanks!
I will try to stick with griddleing, bake/broil, stir fry without oil... Report
We usally grill ms ofour veggies and meat. I had been wonder if this was the best way to cook them. Thank you this was very helpful. Report
I just want to mention that one big reason that veggies lose so many nutrients with boiling is that they are usually put in a lot of water that gets drained off along with the nutrients. I use water in most of my veggie cooking but do it more like a stir fry. I put just a little bit (a tablespoon or 2 or more depending on the veggie) in the pan, cover it (a glass cover works best for visibility) and stay right there with it. You definitely don't want the water to dry up. The cooking goes very, very fast and if you put a bit of seasoning on it, (always use a natural, mineral-balanced salt; never, ever conventional table salt) then, even if there's a bit of water left on the veggies it tastes like a robust broth. Usually there is little or no water left in the pan and your vegetables come out fresh, colorful, and tasty with a good deal more of their nutrients left without the use of oils, which, with a lot of them, if you heat past a certain point become very unhealthy. If I want the flavor of olive oil then I drizzle a teaspoon over the veggies on my plate. That method works so well and so fast!
Of course, some nutrients are lost simply because of the heat. Some things are best eaten raw to get full benefit. I like to incorporate both in my diet.

PS: those carcinogenic compounds will be present in your oil-cooked veggies--not from the veggies themselves but from the oil that's been subjected to high heat whether you grill, roast or saute. Some "experts" on the subject tell us to never use olive oil in cooking because it has such a low smoke point. Boy, isn't that a jump from the norm!! Just worth thinking about.

Oh, also, I cook fish and chicken this way too. It's called "poaching" but I use very little water. I season the water just like you would for poaching with a bit of lemon juice and white wine along with seasoning of choice...YUM!! Report
I steam my veggies in a veggie steamer, or in a microwave steam pouch. I like my veggies crisp-tender, so stir-frying in water, a tsp of olive oil, or non-stick spray is delicious, too. However, nothing beats grilled asparagus! Great article, and super to hear that I'm using good cooking choices. Report
Thanks for the article! I love roasting all my vegetables. Report
Thanks for this article. It was very, very informative. I'm going to pass this on to everyone in my family. We love roasting veggies in the winter and grilling them in the summer, love soup, and now my husband's an even bigger fan of celery! Report
I love grilled veggies in the summer on the BBQ! So delicious! Nothing beats them! Report
I usually microwave mine, so I'm glad to hear that it's a healthy way to do it. I've read that microwaves can be toxic to your health, though, too. There's always two sides to every story! Report
This has been one of the best, common-sense blogs I've read about cooking veggies. Thank you for the information! Report
Great Blog. I learned a lot. Report
Hi and Thank You for the Follow up. I know I, and I'm sure many others asked about soup. I love soup and now am glad to know that I'm not loosing to many nutrients. The picture with this article, penne pasta and veggies w/ cheese and herbs, looks sooo yummy... Report
Roasted...I have gotten my vegetable hating DH to eat more vegetables this is also fairly quick Report