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Sizzle time

(article, Rebecca Kessler)

Raw veggies are better for you than cooked, or so most people think. But according to a new study, it ain’t necessarily so. Home cooks and devotees of a raw-food diet alike may be surprised to hear that cooking can maintain or even improve vegetables’ natural antioxidants and other cancer-busting compounds.

Nicoletta Pellegrini, of the University of Parma in Italy, and her colleagues studied the nutritional effects of boiling, steaming, and frying on carrots, zucchini, and broccoli. They analyzed both the veggies’ levels of individual antioxidant compounds and their “total antioxidant capacity,” or TAC — a technical term that sums up the ability of foods to neutralize free radicals. 

Their results, published in the Journal of Agricultural and Food Chemistry, show that whatever the method, the veggies’ TAC improved with cooking. But the results of the individual-antioxidant analysis were more complex: Depending on the method and the vegetable, cooking might enhance, maintain, or harm specific antioxidant compounds.

In carrots, boiling boosted a suite of antioxidant compounds called carotenoids, but steaming and frying (the worst offender, as you might have predicted) killed them off. On the other hand, all three cooking methods reduced levels of the other antioxidants Pellegrini looked at: polyphenols and ascorbic acid. Most antioxidants held steady in boiled zucchini, but declined in steamed or fried zucchini (again, the latter was the more damaging technique). 

Broccoli had yet another story. Boiling and steaming increased carotenoids. And compared to the raw stuff, steamed broccoli had far more glucosinolates, or cancer-fighting compounds unique to broccoli and other members of the brassica genus, such as cauliflower and Brussels sprouts. 

As in life, so with food; rarely are choices as cut and dried as “raw is good, cooked is bad.” Pellegrini says she thinks it may eventually be possible to match specific veggies with cooking methods to maximize their health benefits. Meanwhile, the best advice is simple: Just eat your dang veggies.