October 28th, 2011
04:21 PM ET
Every weekday, a CNNHealth expert doctor answers a viewer question. On Friday, it's Dr. Melina Jampolis, a physician nutrition specialist.
Asked by Katherine in California
Does diet really make a difference when it comes to breast cancer?
Since October is Breast Cancer Awareness month, this is the perfect time to answer this question.
And the answer is a resounding yes. To get you the best possible information, I turned to registered dietitians Sally Scroggs, MS,RD,LD, and Clare McKinley, RD,LD, at the University of Texas M.D. Anderson Cancer Center, one of the leading cancer hospitals in the world. They explained that breast cancer risk could be decreased by up to 38% through lifestyle factors including maintaining a healthy weight, exercising regularly, and eating a healthy diet. In fact, less than 10% of breast cancer appears to have a genetic basis.
For prevention of breast cancer, limiting alcohol to one drink a day (5 ounces of wine, 12 ounces of beer, or 1.5 ounces of spirits) is one of the most important things that you can do. In addition, a plant-based diet loaded with at least two cups a day of a variety of produce is beneficial.
According to the American Institute for Cancer Research, "no single food or food component can protect you against cancer by itself. But scientists believe that the combination of foods in a predominantly plant-based diet may. There is evidence that the minerals, vitamins and phytochemicals in plant foods could interact in ways that boost their individual anti-cancer effects. This concept of interaction, where 1 + 1 = 3, is called synergy."
Some of their top picks for cancer prevention include beans, berries, cruciferous vegetables (broccoli, cauliflower, cabbage, brussels sprouts), dark leafy green vegetables (spinach, kale, chard, romaine, mustard greens), flaxseed, garlic, grapes/grape juice, green tea, soy, tomatoes and whole grains. A recent study in mice suggests that walnuts may also play a role in breast cancer prevention, but these findings need to be confirmed in humans.
There is also a growing body of research suggesting that curcumin, one of the active components of curry, may play a role in both the treatment and prevention of various types of cancer including breast cancer.
Being overweight is strongly associated with the risk of postmenopausal breast cancer. Adult weight gain of 22-44 pounds is associated with a 50% greater risk and a weight gain above 45 pounds is associated with an 87% increased risk.
Excess belly fat seems to be particularly harmful, most likely because of its effects on inflammation and its association with elevated insulin levels, so if you tend to be more "apple shaped" and carry extra weight in your belly, it is especially important to lose weight, exercise regularly, and limit refined grains, sugar sweetened beverages, and added sugar in your diet.
When it comes to breast cancer survivors, a healthy lifestyle is just as important, if not more so. Many women are concerned about soy consumption, which I've written about before. Sally and Clare agree that up to three servings per day is safe, but they emphasize that soy should come from whole foods like soy milk, edamame and tofu, and that supplements like smoothies, bars and soy fortified cereals should be limited.
Finally, during treatment, diet is very important to maintain health and optimize energy levels, but before taking any supplements, it is best to consult with a registered dietitian, preferably one that has experience with cancer treatment, because some supplements may actually interfere with chemotherapy or radiation.
In general, the emphasis should be on whole foods rich in anti-oxidants. Vitamin C may need to be supplemented in some cases if not enough is consumed in the diet. To find a registered dietitian, go to the American Dietetic Association website.
I hope you are encouraged by the fact that you can make a difference in your risk of breast cancer through lifestyle. Here a few breast cancer fighting recipes from M.D. Anderson to get you started in the right direction.
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