1/9/09

Soy Intake and Breast Cancer

Soy Intake and Breast Cancer
GOOD QUESTION: I'm confused about soy. Is it that those of us who had breast cancer should not use soy powder or eat tofu, etc., or is it that some people were taking too much soy powder and therefore the rest of us were cautioned against it?
GOOD ANSWER: The soy question is definitely confusing and controversial. Here is the concern about soy: The estrogen-like substances (isoflavones) in soy may stimulate the estrogen receptors of breast cancer cells and make them grow. It's this potential danger that makes many doctors warn their breast cancer patients against eating soy products.
On the other hand, there are some that believe that soy may protect a woman from breast cancer. Why? Because the strength of the soy isoflavones' estrogen-like powers is weak — like 1/1000th the "umph" of estradiol, your own body's regular estrogen. If the weaker soy isoflavones occupy the estrogen receptors instead of your body's stronger stuff, then the belief is that the receptors will be less "turned on," and the cells will be less likely to grow. These soy enthusiasts believe that the lower risk of breast cancer seen in Asian women living in Asia may be due in part to their use of soy as their main source of protein. (Of course, it isn't that simple, since these same women are doing other things that may reduce their risk: not smoking, minimal or no alcohol use, regular exercise, likelihood of being close to their ideal body weight, minimal consumption of animal fats from limited use of meats and dairy products over a lifetime.) So now you're probably asking: "What I am supposed to do until this whole controversy is worked out? I'd like to know how to make healthy choices for myself today — not 5 years from now when the answer is in!" Here's where you just have to rely on your best judgment and the cautious recommendations of responsible scientists, dietitians, and of course your own doctor, and research. It's OK to eat soy in the form of soy foods up to a few times per week, as a healthy source of protein (no cholesterol; many fat-free products are also available) instead of chicken and meat. You should not feel comfortable with using significant amounts of the processed soy products that come in the form of powders, tablets, capsules, drinks, etc., because it's entirely unknown if the soy isoflavones are safe in such high concentrations. Who knows — maybe they might stimulate the breast tissue excessively at such high levels. So try to eat a well-balanced diet with plenty of fruits and vegetables and grains (soybeans are beans). Buy organic and wash all produce off well. Don't overcook them. Use high-fat dips and salad dressings sparingly. When it comes to food (and other things too, of course), make sure you enjoy yourself. Your breast cancer experience has already "stolen" some of your joy, and now is the time to find ways to rediscover the pleasure in living — not to destroy it. Don't punish yourself with unrealistic expectations and things you don't like. Moderation is key. Life is too short to be fighting with yourself. You must believe that this is very important.

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