Steam vegetables   Steaming helps retain cancer-fighting nutrients in broccoli better than other cooking methods, reports a new study from the University of Illinois at Urbana-Champaign. Sulforaphane—a plant compound with strong anti-cancer properties—is abundant in cruciferous vegetables like broccoli, cauliflower, kale, and arugula. The enzyme myrosinase is necessary to release the compound, but most cooking methods destroy it. Steaming is a slower, gentler heat, and isn’t intense enough to kill myrosinase

 

Eat strawberries whole   Whole strawberries contain 8 to 12 percent more vitamin C than the cut fruits, according to a 2011 Brazilian study. That’s because vitamin C begins to break down when it’s exposed to light and oxygen.

 

Heat tomatoes up   Tomatoes may lower your risk of stroke, fight prostate cancer, and preserve brain power as you age—that's why they made our list of the 40 Foods with Superpowers. But heating tomatoes significantly increases their levels of lycopene, the chemical that can raise antioxidant levels.

 

Do not skip frozen fruits and vegetables     U.K. scientists found that in two out of three cases, frozen fruits and vegetables packed higher levels of antioxidants—including polyphenols, vitamin C, and beta-carotene—than the fresh kind. As produce ages, nutrients begin to change and break down. It's therefore better to eat food that was frozen at prime ripeness with its nutrients intact than week-old produce that no longer has the same beneficial chemical makeup.