Is there a right or a wrong way to cook a vegetable? If you want to unleash all its disease-fighting superpowers, then the answer is probably yes.
And as scientists poke and prod the inner world of vegetables down to the molecule, they've learned that broccoli is among the veggies sensitive to cooking technique. If cooked more than a few minutes, broccoli's antioxidants aren't as adept at knocking out carcinogens that cause cancer. And if you want broccoli to do just that – fight cancer — forget about taking broccoli supplements, which don't hold a candle to the whole vegetable, an expert says in a new paper.
A lot of other vegetables are packed with vitamins, minerals and valuable chemicals that can be unlocked or blocked, depending on preparation and the foods they're eaten with, as The Salt's co-host, Allison Aubrey, has reported. Tomatoes are best eaten with a little fat, like olive oil, while carrots may be more willing to offer up their antioxidants when cooked.
But as Emily Ho, an associate professor and researcher at the Linus Pauling Institute at Oregon State University, tells The Salt, cooking broccoli too long destroys the enzyme that breaks down chemicals called glucosinolates into cancer-fighting agents. That means a savory cream of broccoli soup, for example, is sadly not going to showcase broccoli at its nutritional best.
But choppin' broccoli is still just fine, as fans of Dana Carvey's classic Saturday Night Live skit will be glad to hear.
And the best way to eat it once chopped is raw or steamed for just two to three minutes.
This applies to other cruciferous veggies – like cauliflower, kale, wasabi and cabbage — too, says Ho, who's been studying broccoli for years. These vegetables all have compounds that can "target sick cells and keep normal cells happy, which is what you want for cancer prevention," Ho says.
Her latest paper, published in the Journal of Agricultural and Food Chemistry, however, shows that most broccoli supplements don't have enough of the good enzyme that will put those compounds to work.
Ultimately, Ho says, the best way to use food to prevent cancer is to eat five to nine servings of fruits and vegetables a day and eat a wide variety of them. The way cancer does damage in the body is, after all, pretty complex stuff, and each fruit or vegetable may play a different role in helping fend off disease.
Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.