Nov. 1, 2007 at 12:25 PM ET
About 178,480 women in the United States will be found to have invasive breast cancer in 2007; it’s the most common type of cancer among women in the United States, other than skin cancer. While some of the risk factors for breast cancer are not within our control, such as gender, age or family history, there are some factors that are within our control, such as diet and exercise. In regard to lifestyle, here’s what research suggests:
Maintain a healthy weight
Studies show that maintaining a healthy weight (especially for postmenopausal women) is an important aspect of decreasing one's risk of developing breast cancer. In fact, one study showed that obese women (BMI >30) had a 31 percent greater risk of developing breast cancer compared to women of healthy body weight (BMI < 25). Why? Excess weight may lead to elevated levels of the hormone estrogen, which may be involved in the development of breast cancer.
One study showed that women who engaged in strenuous recreational activity for more than six hours a week had a 23 percent reduction in risk of breast cancer. Other studies indicate that anywhere from five to seven hours per week decreases risk. Even active housework has been shown to reduce your risk!
Watch the amount and type of fat you eat
Research suggests that greater total fat consumption (about 40 percent or more of daily calories) poses a greater risk for breast cancer than lower total fat consumption (about 20 percent of daily calories). With that in mind, try to limit total fat intake to less than 30 percent of daily calories in order to help in the prevention of breast cancer.
Saturated fats found in marbled meat and high-fat dairy products are more likely to increase risk of breast cancer than unsaturated fats found in nuts, seeds and avocados, as well as olive and canola oils. Try to limit saturated fat intake to less than 7 percent of total daily calories (if you’re following a 2,000-calorie diet, that’s no more than 15 grams).
Incorporate 5 vegetables/fruits a day
Produce provides numerous phytonutrients and antioxidants — substances which help prevent cellular damage throughout the body. One well-designed study found that regular consumption of five or more servings of veggies a day was associated with lower risk of breast cancer; however, according to a recent study published in JAMA, consuming more than five servings doesn’t seem to have any preventative effect. So when it comes to breast cancer prevention, I say aim for at least five daily servings of colorful produce.
Tip: Cruciferous vegetables such as broccoli, cabbage and brussels sprouts are particularly strong fighters (studies show they inhibit growth of breast cancer cells).
Studies show that above moderate (one or more drinks per day) consumption of alcohol is associated with increased risk of breast cancer. Alcohol may raise estrogen levels and decrease the body’s ability to use folic acid, a B vitamin that’s been linked to cancer prevention. To help minimize risk, stick with the Dietary Guidelines for Americans, which recommends no more than one alcoholic drink per day for women (one serving = 12 fluid ounces beer, 5 fluid ounces wine, or 1.5 fluid ounces of 80-proof distilled spirits).
Limit meats cooked at high temperatures
Cooking meats at high temperatures produces chemicals called heterocyclic amines (HCAs), which have been linked to an increased risk of certain cancers. Studies have shown that the risk is higher among people who eat meat (specifically beef) four or more times per week, and who cook their meats more thoroughly. The most HCAs are found in meats that have been fried, broiled or grilled — all cooking methods that typically use high temperatures. Roasting and baking produce fewer HCAs, and poaching, stewing or boiling meat produce the least.
I recommend limiting your intake of red meat altogether (aim for no more than three times each week), and cut back on your consumption of all meats cooked at high heat. When you do grill steak, pork and poultry, just be sure to trim excess fat, flip often and cut off charred or burnt parts of food before eating them (you may also want to cook meat slightly in the microwave or oven first, to lessen high-temperature cooking time). Also, marinate your meat before cooking — it helps to lessen HCA formation — and consider cutting meat into smaller chunks (they’ll cook faster, spend less time on the grill and you’ll reduce the likelihood of carcinogens forming).
Vitamin D deficiency has been linked to several cancers, including breast. I recommend eating plenty of vitamin D–rich foods (salmon and sardines), and choosing vitamin D–fortified milk, yogurt and cheese. Because few foods provide vitamin D, you should consider a daily multivitamin that provides 100 percent DV of vitamin D3. If you think you’re a candidate for even more, speak with your physician.
Phytoestrogens are a group of plant-derived compounds that are structurally and functionally similar to the hormone estrogen, which is found naturally in our bodies. There are several different groups of phytoestrogens; the most widely studied are the isoflavones, present in highconcentrations in soy products such as soybeans, tofu, tempeh and soy milk.
When it comes to breast cancer, there has beensome evidence that soy can play a protective role; however, its effects may depend on when in life it’s consumed. For example, Japanese women eat soy throughout life, whereas most American women may have only started eating soy as adults. It’s been proposed that isoflavones act as anti-estrogens in premenopausal women who have high circulating hormone levels. But after menopause, when estrogen levels are low, they may act like estrogens and any estrogen boost, even if weak, may at least theoretically be harmful in such women. The optimal amount of dietary soy is unknown — and different forms of soy may have different effects. For example, highly processed soy foods (meat analogues and energy bars) may have less biological activity than whole soybeans or soy milk.
What’s the bottom line? A moderate amount of soy consumption can be part of a healthy diet (1-2 servings daily), particularly in premenopausal women. A serving = ½ cup tofu, tempeh, edamame (out of the pod), ¼ cup soy nuts or 1 cup soy yogurt or soymilk. **However, if you have or have had breast cancer, or you’re at high risk, it’s important you speak with your personal physician and follow their expert advice when it comes to soy consumption. This remains a controversial topic and you may be instructed to completely avoid.
Important: Always avoid soy supplements — they may contain higher levels of isoflavones than present in soy foods without the other potentially healthy components. Long-term effects are not yet known.
Spice it up with curcumin!
Recent studies show that curcumin, the yellow spice found in turmeric and curry powder, may have anti-tumor compounds that can protect against breast cancer. Try these quick and easy tips to add curcumin to your diet:
Joy Bauer is the author of “Food Cures.” For more information on healthy eating, check out Joy’s Web site at www.joybauernutrition.com