Can what you eat help prevent (or promote) breast cancer? Yes" probably, but exactly how is not yet clear. How do we make sense of all the studies on diet and cancer?
Let’s start with this understanding, relating to a common breast cancer myth: recent studies have not found significant decreases in the incidence of breast cancer when consumption of fruits and vegetables was increased. Keeping breast cancer at bay is not as simple as eating your fruits and veggies every day.
At the same time, nutritionists and researchers are coming to a solid understanding of the link between certain foods and breast cancer, based on a number of long-term studies. The following recommendations aren’t a sure thing, but they’re the research community’s best guesses to date. Here’s the latest:
- Antioxidants: Without taking a deep dive into molecular biology, antioxidants help prevent your body’s cells from being damaged. Damaged cells often grow out of control, which can lead to cancer. Ergo, consuming antioxidants can help prevent cancer. What foods contain lots of antioxidants? LOTs of foods, luckily. Here are the best sources:
, avocados, cherries, pears, plums, prunes, pineapple, oranges, and kiwi fruit.
, and broccoli.
; and kidney, pinto, and black beans.
Nuts: Walnuts, pistachios, pecans, hazelnuts, and almonds.
Spices and herbs: Ground cloves, cinnamon, ginger, dried oregano, and turmeric.
Beverages: Green tea, coffee, red wine, and most fruit juices. BUT, despite its high antioxidant level, breast cancer survivors should generally avoid alcohol; go for grape juice instead.
And finally, oatmeal; and dark chocolate (bittersweet or semisweet).
- Soy: Tofu, or not tofu" that is the question. Back and forth we go. First soy is supposed to help prevent breast cancer. Then it’s said to promote tumor growth in rats. What’s the latest on the humble soybean? Most recent studies show that the phytoestrogens (plant estrogens) in soy may actually shoulder aside some of your own human estrogen. And since plant estrogens don’t "feed" breast cancer cells like human estrogen, that’s a good thing. Bottom line: It appears soy may play a role (though a modest one) in the prevention of breast cancer recurrence in postmenopausal women. And women with naturally higher levels of estrogen will benefit more than women with lower levels. If you like tofu and soymilk-go for it! If you don’t-don’t force the issue. There are plenty of other good-for-you foods out there. P.S. Flaxseed is a strong second to soy as far as phytoestrogen content; sprinkle it on your morning cereal.
- Phytochemicals: Phytochemicals-naturally occurring chemicals found in vegetables-are known to be good for you, and are thought to play a role in preventing breast cancer. They prevent the formation of carcinogens; keep carcinogens from attacking your cells; and help cells rid themselves of cancer-like changes.
The closest association between possible breast cancer prevention and phytochemicals is in cruciferous vegetables, which produce estrogen-like activity in your body, just as phytoestrogens do. The most familiar of these vegetables include broccoli, cauliflower, arugula, kale, Brussels sprouts, collard and mustard greens, turnip and rutabaga, radishes, daikon, and bok choy.
Carotenoids, plant pigments found in brightly colored fruits and vegetables (think red and green peppers, cantaloupe, tomatoes, carrots, acorn squash, and the like) are another type of beneficial phytochemical. One 5-year study of breast cancer survivors showed that the women with the highest level of carotenoids in their blood had a 40% reduced risk of recurrence.
- Good fat: We all need some fat in our diet; what we don’t need are saturated animal fats, like those found in meat and butter. Monounsaturated vegetable fats are good fats, and the best of these are olive oil and canola oil. Olive oil is full of phytochemicals as well as vitamin E, which is an antioxidant. Flavor olive oil with dried herbs, and drizzle it on bread in place of butter. Toss your salad with olive oil and a good balsamic vinegar. Stir-fry veggies. Do your cooking and baking with canola oil: it’s an easy replacement for the bottle of vegetable oil you keep in the cupboard.
- Bad fat: Cut back on it" sigh. This is a song you’ve heard sung for years, and not just in conjunction with breast cancer. Trade that Big Mac for a veggie burger! Go for the reduced-fat yogurt, air-popped popcorn, and a slice of turkey breast instead of a drumstick. Good advice for all of us-but especially for postmenopausal women with ER-negative, early stage breast cancer (breast cancer that’s been confined to the breast and underarm lymph nodes). A seven-year study involving nearly 2,500 breast cancer survivors-the Women’s Intervention Nutrition Study (WINS)-showed that women on a lower-fat diet (about 33g fat per day) experienced a 24% overall reduction in the relative risk of recurrence, compared to women who ingested about 52g fat per day. For women with ER-positive breast cancer, the risk reduction is 15%; for those with ER-negative cancer, it’s a whopping 42%.
- Alcohol: Avoid it, or at least be temperate in enjoying it. The evidence is pretty strong that consuming more than 3 to 4 drinks a week increases your breast cancer risk. Reminder: A drink = 12 ounces of beer, 5 ounces of wine, or 1 1/2 ounces (a shot and a half) of hard liquor. Drink lightly, if at all. Studies show that women who consume 2 to 5 drinks per day have a 41% higher risk of getting breast cancer than women who don’t drink at all. Is it worth it? Your choice.
- Mushrooms: Never mind the Arimidex, I’ll take stuffed mushrooms! A recent study showed that the linoleic acid found in mushrooms seems to inhibit aromatase, an enzyme that helps your body make estrogen. Discourage aromatase" hinder estrogen production" stymie estrogen-receptive breast cancer (the kind 70% of us have). Button mushrooms are said to be the most effective, followed by their larger cousins, stuffing mushrooms; then portobello, crimini, shiitake and baby button mushrooms.
- Fiber: YUM! Come on now, fiber can be very tasty. And bet you didn’t know our old friend fiber likes to bind itself to estrogen, preventing it from feeding tumor cells. So, what’s the easiest, tastiest way to eat more fiber? Whole grains, for sure. Think whole-grain breakfast cereal and oatmeal (which also helps your cholesterol levels). And whole-wheat pita or wraps. In fact, the bread aisle now has all kinds of tasty, moist, soft whole-grain breads, perfect for sandwiches. Then again, you can always bake your own whole-grain treats. I’ve switched from white flour to King Arthur White Whole Wheat Flour for nearly all of my baking. It’s a 100% whole wheat flour that’s lighter in color and milder-flavored than regular whole wheat. I use it in cookies, muffins, bars" everywhere I’d use all-purpose flour. Check out the recipe section at kingarthurflour.com for all kinds of yummy whole-grain treats.
- Eat real food. As opposed to trying to get all your phytochemicals, antioxidants, soy isoflavones, etc. in pill form or supplements. Time and time again, nutritionists and scientists have isolated the nutrients and chemicals in fruits and vegetables, then synthesized them artificially to include in a pill or dietary supplement, and guess what? They’re just not as effective as the original. There’s something about the way all the elements of a fruit or vegetable work in harmony that makes it really, really good for us. It’s better and easier to simply eat an apple than to try to match its benefits by taking a variety of man-made chemical substitutes. Note: I’m not dissing multivitamins, calcium, omega-3 fish oil capsules, or any of those daily pills you take; simply reminding you that supplements should be just that: supplementary to "the real thing."
- Don’t eat too much. Calories in (eating), calories out (physical activity)" Remember, the two have to be in balance, OR weighted a bit towards "more out than in." So, SO much easier said than done. SIGH. It’s a fact: fat produces estrogen, and breast cancer is linked to high levels of estrogen in your body. The more fat you carry, the greater your lifetime risk of breast cancer. According to the American Cancer Society’s Web site, ""researchers found that the greater the weight gain, the greater the risk for all types, stages, and grades of breast cancer." Women who’ve gained 60 pounds during adulthood (that is, you weight 60 pounds more now than you did at age 18) are nearly twice as likely to get breast cancer as women who’ve gained 20 pounds or less. Don’t give in to weight gain; fight it for all you’re worth. Because never forget: you’re worth a lot.
So, do you see a common thread here? Fruits" vegetables" natural foods" whole grains" less bad fat, more good fat" less alcohol, more fruit juice, coffee, and tea" Learn to spend more time in the produce aisle than in that oh-so-tempting cookie aisle, and you’ll be doing yourself an enormous favor. You may also be saving your life.
While cancer prevention is not as simple as eating more fruits and vegetables, nutritionists and researchers know a ton about what makes certain foods good for you. Do you? Test your knowledge.
P.S. Check out Take-10 Super Cookies, a recipe I developed incorporating 10 of the ingredients mentioned above.
PJ Hamel is senior digital content editor and food writer at King Arthur Flour, and a James Beard award-winning author. A 16-year breast cancer survivor, her passion is helping women through this devastating disease. She manages a large and active online survivor support network based at her local hospital and shares her wisdom and experience with the greater community via HealthCentral.com.