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Soy and Cancer

Posted 10/3/2014

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  First a reminder that I will no longer be writing posts on weekends. I suspect that news does not ruin anyone's Saturday or Sunday, but I don't want you wondering or even worrying. After this one, I will be back again on Monday.

  There is always a great deal of conversation about diet and cancer. No matter what your friends tell you, I promise you that there is no such thing as particular foods that will prevent or cure cancer. Yes, there are some foods that we know are especially good for us: e.g. kale and blueberries. But eating even vast amounts of so-called "super foods" won't do a thing directly about cancer cells. It is also worth saying here that sugar does not cause or encourage cancer growth. The association between sugar and cancer cells is way more complicated than that and has to do with cellular level biology. As I think about it, I will ask someone to write a guest post about that one. What you need to remember is that too many sweets are not good for us in general or our waistlines in particular, but that slice of chocolate cake or warm chocolate chip cookie is not dangerous!

 Women with breast cancer, especially those with ER positive breast cancers, worry about soy in their diets. This actually is relevant to some other kinds of cancer, too. There are some GYN cancers that may be associated with estrogen, and men with prostate cancer know that hormones are related and treatment sometimes involves them. Note that the title below is specific to breast cancer, but the information is more generally useful.

  This is a helpful essay from our current Nutrition Intern and even includes a couple of recipes:

The Truth on Soy and Breast Cancer
As a future registered dietitian one of the most popular questions I get from my friends is “Is soy really healthy? I heard that it causes breast cancer. Is that true? How much should I be eating?” As with many other topics in nutrition, people are getting mixed messages on what they should or should not be eating. The media is constantly presenting contradicting information in regards to soy and breast cancer, and it can be challenging to decide whether to consume soy or not. So what’s the truth about soy?

Soy is a great source of lean protein and offers many other health benefits as well. It is low in saturated fat and contains no cholesterol. Soy is rich in calcium, iron, zinc, fiber, potassium and the B vitamins. It is an excellent source of omega 3 fatty acids which has been shown to help reduce ones risk of developing heart disease and high blood pressure. Soy is also full of phytochemicals, powerful plant chemicals that can help our bodies fight off diseases such as cancer, heart disease and diabetes.

The confusion about soy in regards to breast cancer lies within the “phytoestrogens,” the estrogen-like chemicals found in soy products. These phytoestrogens look similar to estrogen, a hormone in our bodies necessary for childbearing which is also possibly related to increased breast cancer risk when over-exposed to over a lifetime. However, what people do not realize is that these phytoestrogens, although sound similar to estrogen, actually are not the same thing! In fact, soy does not contain any estrogen at all.

Evidence shows that it is safe for women to eat soy regularly, and some studies actually show it may be beneficial for breast cancer survivors to consume soy. Based on current research, it is recommended that people who want to include soy in their diet stick to whole soy foods such as tofu, tempeh, soymilk or soy nuts. There is not sufficient research when it comes to the safety of soy pills and supplements and how it behaves in mimicking estrogen in the body, so for now it is recommended to stick to the whole food sources of soy. Plus, eating the real thing tastes much better than a pill anyway. So bon appétit!

Be creative with your soy! Here are some tasty soy recipes to try out:

Soy Banana-Oat Pancakes
½ c rolled oats
½ c unbleached flour
¼ c soy flour
1 tablespoon baking powder
1.5 c plain soy milk
2 bananas, thinly sliced

Combine all ingredients except bananas and mix together. Once mixed, gently fold in the bananas. Pour ¼ cup batter onto a hot nonstick pan and cook for about 2 minutes or until bubbles appear, then flip and cook for another minute.
Tastes great with maple syrup or fruit on top.
Makes 12 pancakes, 103 calories, 3g protein, 1g fat, 20 g carbs

Creamy Tomato Soup
2 tsp vegetable oil
1 medium onion, diced
1 cup soymilk, plain
1 (12 oz.) pkg firm lite silken tofu
1 large tomato, diced
1/2 tsp salt
1/2 tsp chopped garlic
1 tsp fresh basil, chopped
1/2 tsp white pepper

Cook onion in sauce pan in oil for 3 minutes or until transparent. Add tomato and garlic, continuing to cook for 2-3 minutes. Add basil, salt, and pepper. Blend in soymilk. Cook, stirring constantly, for 1 minute. Remove from heat and cool briefly.
Add in tofu. Transfer to food processor and purée until smooth. Serve hot or chilled.
Makes 3 servings, 181 calories, 8.5g fat, 0mg cholesterol, 450 mg sodium, 17g carbs, 12g protein, 3g fiber

If you have any questions regarding soy or other nutrition questions in regards to cancer, feel free to reach out to Registered Dietitian, Lauren Fay, at or call 617-667-2565.

Julie Levine, BIDMC Dietetic Intern



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