More Vegetables Mindlessly, Part 2

Last week we described how vegetables magically become more appealing when dubbed fancy names like “X-ray vision carrots.” And by now, you and your kids are doubtless shoveling in the carrot sticks by the fistfuls.

Now, on to more pressing question: should you stir-fry, steam, or boil?

It’s actually an important question to consider, because the cooking method you choose has a significant effect on how much of a veggie’s nutrients your body receives.

Researchers in Murcia, Spain, discovered that just by boiling celery, the veggie lost 14 percent of its antioxidants–powerful nutrients that help fight cancer. [i] Food scientists in England measured the glucosinolates–another cancer-fighting nutrient–in broccoli, Brussels sprouts, cauliflower, and green cabbage after boiling. Boiled broccoli lost 77 percent of these key anti-cancer ingredients; cauliflower, 75 percent. When the English researchers tested the boiling water, they found the missing health-boosters–90 percent of the missing glucosinolates ended up in the cooking pot.[ii]


Clearly, boiling isn’t the way to go. But you’ve still got a variety of options–from microwave to steam to stir-fry. All of these methods work just fine, but here are a few facts to keep in mind as you choose the best way to cook up your daily dose of plants:

  • Steaming is good. Vegetables cooked in a steam basket–out of contact with hot water that drains their cancer-fighting properties–retain nutrients and also taste delicious.
  • Stir-frying is better. Not only does this cooking method preserve more nutrients than boiling, it also offers cardiovascular perks. Researchers in Spain found that compared to a low-fat diet, eating a Mediterranean diet supplemented with nuts and olive oil had a beneficial effect on cardiovascular risk factors.
  • Olive oil is best. The Spanish researchers also evaluated the effect of stir-frying broccoli with different oils: refined olive oil, extra virgin olive oil, sunflower oil, peanut oil, soybean oil, and safflower oil. Compared to all the oily options, broccoli stir-fried with extra-virgin olive oil retained the most nutrients.[iii]


[i] Jiménez-Monreal, A. M., García-Diz, L., Martínez-Tomé, M., Mariscal, M. and Murcia, M. A. (2009), Influence of Cooking Methods on Antioxidant Activity of Vegetables. Journal of Food Science, 74: H97–H103. doi: 10.1111/j.1750-3841.2009.01091.x

[ii] Song L., Thornalley P.J., Effect of storage, processing and cooking on glucosinolate content of Brassica vegetables, (2007) Food and Chemical Toxicology, 45 (2), pp. 216-224.

[iii] Moreno, D. A., López-Berenguer, C. and García-Viguera, C. (2007), Effects of Stir-Fry Cooking with Different Edible Oils on the Phytochemical Composition of Broccoli. Journal of Food Science, 72: S064–S068. doi: 10.1111/j.1750-3841.2006.00213.x

September 27, 2011

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