This week's post comes from guest blogger Heather Mason, MS, RDN. For Breast Cancer Awareness month she tackles a tough question that is often asked. Keep reading to find her response.  


October is breast cancer awareness month. It’s a great time to donate to a cancer charity and it is also a great time to think about lifestyle choices which may affect your risk of developing cancer. A healthy diet and regular exercise are two lifestyle factors which play a role in reducing the risk of breast cancer.  A diet rich in fruits and vegetables has been shown to be beneficial in the prevention of breast cancer, prostate cancer, and colon cancer in epidemiological studies (studies looking at large populations). On the other hand, we often hear that there are some foods which may increase our risk for cancer. One frequently mentioned is soy. Many people have heard talk of soy being unhealthy, while some people think it’s healthy, what’s the deal?

To understand the interplay of soy and breast cancer we must first understand the components of soy. Soy foods such as tofu, edamame (soy beans), soy milk, and vegetarian “meats” contain isoflavones which are chemically similar to estrogen. Isoflavones can act like estrogen in the body, although they are much, much weaker than naturally occurring estrogen that your body produces. Keep in mind that soy foods do not contain estrogen. Soy also has antioxidant and anti-inflammatory properties which can work to reduce cancer growth.

In human studies the consumption of soy has either been shown to have no effect on breast cancer or it has had a positive effect. Meaning soy consumption was associated with reduced risk of developing breast cancer. Asian women have lower rates of breast cancer than American women; one of the possible reasons for this is a higher consumption of soy. In certain Asian populations soy is consumed as the main protein over chicken or meat. However, it is important to keep in mind other dietary and lifestyle factors that may affect the rate of cancer.  For example, Asian countries have different rates of fish consumption, fruit and vegetable intake, and on average, Asian women have a lower body mass index (BMI) than American women.

It is important to note that while the preliminary evidence on soy does look positive, the use of soy supplements to prevent cancer is currently not recommended. The supplements contain much higher doses than one would naturally consume in food and there has not been enough research performed regarding their safety and effectiveness at this point.

Another benefit of soy is that it is a high quality vegetarian source of protein. Several studies have shown that frequent red meat and processed meat consumption does increase your risk for heart disease and some cancers. Going vegetarian at least once a week with soy may be a positive change to your diet. Some of my favorite sources of soy are Morning Star Veggies Burgers, edamame (lightly salted or roasted with garlic) and cashew nut chicken with tofu instead of chicken. Do you eat soy? What soy foods do you like? 




Heather Mason is a Registered Dietitian who holds a Master’s Degree in Nutrition Science.  She currently works at Sierra Vista Medical Clinic where she counsels adults and children with diabetes, obesity, and cardiovascular disease.  She has a passion for blogging and delivering her healthy eating message in a fun and humorous way.  Her hobbies include baking and cooking, snowboarding, and any outdoor activities.  She is also an avid group exerciser and loves teaching Zumba Fitness classes. You can read more posts from her on her blog The Nutty Nutritionist. Follow her on Twitter @HeatherRDN.