More than 200 studies from around the world have shown that a diet high in fruit and vegetables lowers the risk of many cancers, including breast cancer. Researchers from Harvard University studied more than 89,000 women and found that those who ate more than 2.2 servings of vegetables a day had a 20 percent lower risk of breast cancer than those who ate less than one serving.8 Another study in premenopausal women found that high total vegetable intake lowered the risk of breast cancer by 54 percent.9
It appears that dark green vegetables are most protective. Spinach, kale, rapini, collard greens, Swiss chard and romaine lettuce are good sources of beta-carotene, an antioxidant nutrient that might protect breast cells from damage caused by harmful free radical molecules—free radicals roam the body and damage the genetic material of cells, which may lead to cancer development.
Popping beta-carotene pills does not have the same protective powers. Scientists are learning that there’s more to fruits and vegetables than vitamins, minerals and fiber. They also contain thousands of phytochemicals, naturally occurring compounds that act as antioxidants and natural antibiotics, and so may inhibit cancer development. Experts believe that phytochemicals probably work together with vitamins and minerals in the food. In a nutshell, it’s the whole food that seems to be most important in cancer prevention.
Make sure you get at least five to ten servings of fruits and vegetables each day. Aim for a minimum of three fruits and three vegetables. Here are a few ways to get more “green” into your diet:
• Spinach One-half cup (125 ml) of cooked spinach provides your full day’s requirement of vitamin A and offers plenty of folate (read more about the possible role of folate in breast cancer prevention in the section on Vitamins and Minerals on page 145). Spinach is also an excellent source of vitamin C. One-half cup (125 ml) cooked has more nutrition than 1 cup (250 ml) raw because it contains 2 cups (500 ml) of leaves, and heating makes the protein in spinach easier to break down. Steam, braise or stir-fry with a little garlic; add a splash of balsamic vinegar at the end of cooking.
• Kale Just 1 cup (250 ml) of this member of the cabbage family provides more than twice the daily requirements of beta-carotene and vitamin C. Kale is also a good source of calcium and vitamin E, another important antioxidant. Steam or stir-fry this green with other vegetables, or throw kale into soup and simmer. Kale shrinks a lot during cooking; 3 cups (750 ml) raw will give you 1 cup (250 ml) cooked.
• Collard greens In addition to plenty of vitamins and minerals, this vegetable contains natural sulfur compounds that may prevent certain cancers. Stir-fry collards then add a dash of roasted sesame oil and a handful of cashews.
• Beet greens The next time you buy fresh beets, save the greens and eat them, too. The green tops of root vegetables have more nutrition than the root when it comes to vitamins and minerals. These greens are a good source of vitamins A and C, as well as calcium and iron. Prepare them as you would any green.
• Swiss chard Here’s another great vegetable that provides calcium, beta-carotene and vitamin C. Use both the leaves and the stalks when cooking, but add the leaves at the end of cooking, as the stalks take longer to soften. Stir-fry Swiss chard with a little olive oil and garlic, or add lemon juice and Parmesan cheese; it’s also great in pasta with a little olive oil and red pepper flakes.