Breathe Easier With Fruits and Veggies
In addition to beta-carotene, the study also included four other carotenoids: alpha-carotene, lutein, lycopene, and beta-cryptoxanthin. Alpha-carotene is found mostly in carrots, lutein is found in green, leafy vegetables such as spinach and kale, lycopene is found in tomatoes, and beta-cryptoxanthin is found mostly in oranges. "Beta-carotene is found in carrots, but also a lot of other vegetables as well -- you get a little of it from a lot of different vegetables," says Michaud.
Although many people take beta-carotene supplements, "if anything, the association [with reduced lung cancer risk] was stronger for alpha-carotene than beta-carotene," she notes. For instance, among nonsmokers, those who ate the most fruits and vegetables containing alpha-carotene had a 63% decrease in lung cancer risk compared to those who ate the least of these foods.
John Weisburger, PhD, a senior member of the American Health Foundation in Valhalla, N.Y., explains that while carotenoids undoubtedly play a role in neutralizing free radicals, "fruits and vegetables also contain other antioxidants, like quercitin, that may also play a role," he says.
Although the study's findings apply to smokers and nonsmokers alike, Michaud has a message for smokers in particular. "We want to re-emphasize that for lung cancer, the most important thing is to have people stop smoking," she says. "Then, on top of that, diets rich in fruits and vegetables provide protection as well." Smoking accounts for more than 90% of the lung cancer cases seen yearly.
Michaud adds, "We're not sure exactly what's in vegetables that gives protection, so it's important to eat the fruits and vegetables and not just take a pill."