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Does Cooking My Vegetables Hurt Their Vegetable-ness?

I’m not gonna even ask about the pound of butter I require in order to choke them down

As a child of the 1980s, I was frequently apprised of “The Three Demandments of Hulkamania”: “Train, say your prayers and take your vitamins.” Well, I never got my hands on a bottle of the Hulkster’s vitamins, and I was inculcated to think that the majority of my vitamin intake would have to come through the ingestion of vegetables.

The best kept secret about vegetables is that they have varying tolerances to heat, and depending upon the vegetable, this can obliterate some or all of the micronutrient content contained therein. What this amounts to is that the nutrient content provided on the labels of your favorite vegetables — especially if you purchase them in pre-portioned packages — is a cross between a best-case scenario and wishful thinking. In most cases, the full nutrient value of the vegetable won’t be accessible unless you consume it completely raw, while in other cases, heat is actually required to unlock the absorbability of the veggies. 

No matter what you do, unless you know the specific chemistry of the vegetable in question and how to unlock its peak value, you’re never going to be able to maximize the nutrient quality of your food. Even then, the percentage of vitamin absorbed is going to be a best guess — i.e., you can never know for certain.

Wait a minute, this is insane! You’re telling me that I’m not getting the full benefits out of my nightly McDonald’s side salad?

That thing? It’s lettuce, a single slice of tomato and two cucumbers — there are more nutrients in a serving of Bloody Mary mix. Also, the answer to your question is “definitely not,” but I’ll get into that a little later on. McMenus aside, it all depends on what’s in the salad, but we should probably start with the vegetables you’re preparing on top of your stove or inside of your oven.

Let’s suppose that you’re of the belief that frozen vegetables are no good, and that any amount of processing irreparably ruins food. So instead of buying the Birds Eye California Blend consisting of broccoli, cauliflower and carrots, you rush off to the produce aisle, bag the component vegetables yourself, chop them up and boil them all together. “My vitamin A and vitamin C intake is going to go straight through the roof!” you cackle gleefully. “I’ll never get sick again, and I can now toss my prescription eyewear into the garbage!”

Not so fast. You need to be very careful with respect to your food-preparation choices, or again, you may end up massively reducing the quantity of vitamins available for you to absorb. Vitamin C is a water-soluble vitamin, and the combination of heat and water will deplete the quantity of it contained in the vegetables, and cause it to leach into the water it’s being cooked in. As a result, the act of boiling your self-made California Blend is going to reduce the presence of vitamin C with every second that passes. In fact, if you’re one of those people who boils the crap out of your vegetables, you can degrade their vitamin C content completely. This applies to all of the water-soluble vitamins, which absolutely lose some of their potency when you heat them in water.

That’s cool. I’d much rather prepare everything in cooking oil or butter.

I see where that might seem like a tasty alternative, but now you’re opening yourself up to a new method of degrading vegetables’ nutrients. 

Remember the vitamin A from the carrots in our California Blend? Well, much like vitamins E, D and K, vitamin A is fat-soluble, which means that it has a tendency to be degraded somewhat when it’s cooked in a fatty substance like butter, oil or margarine. During testing, when vegetables were fried in a shallow pan containing a fat-heavy substance bereft of additional antioxidants, the loss of fat-soluble vitamins ranged from 30 to 70 percent.

So this presents us with a quandary: Fat-soluble vitamins need to be accompanied by fat in order for the body to fully absorb them, but incorporating fats into the cooking process causes the vitamins contained within those vegetables to become somewhat degraded, thereby defeating the process somewhat. What’s a person to do?

This is frustrating! Can I just sidestep this whole process by eating my veggies raw?

That’s the way ODB would have liked it, but is consuming vegetables raw the answer to all of our problems?

Not necessarily. Even though eating a vegetable raw guarantees that all of the potential nutrients enter your body, the way a vegetable is prepared can also influence its absorbability and digestibility. For example, a study found that the absorbability of lycopene from tomatoes was found to increase by 35 percent when it was heated, and provided a significant boost to the tomatoes’ antioxidant activity as well. This increase in antioxidant activity was found to have increased when heating carrots, spinach, mushrooms and several other vegetables, too. So the raw tomato from your McDonald’s side salad can never contribute to your health as much as you’d like it to.

I’m so confused. Is there no one correct way to eat my vegetables?

Unfortunately, there isn’t, but that’s okay. If your goal in eating vegetables is to extract as much micronutrient content from them as you can, I’d simply advise you to eat sizable portions of them from a wide swath of sources. It couldn’t hurt either to throw a daily multivitamin into the mix. 

Furthermore, try to eat your foods completely, including everything in the environment they’re cooked in. Some vitamin content that’s lost in the preparation process is still stored in the surrounding water and juices, and up to 90 percent of some vitamins can be recovered by consuming those juices. Or to put it another way, consume all of the fluids emanating from the veggies you’re consuming like a human Bunnicula.

At the same time, always remember that vitamins aren’t the be-all-end-all of health. The contents of your food are crucial to your well-being, but micronutrients aren’t medicine, they aren’t mystical and they certainly aren’t magical. So do the best you can, but don’t waste hours trying to extract every last nutrient from every last vegetable, because sometimes you need to see the forest through the trees. Or I guess in this case, the salad through the lettuce.