Nutrition is an important part of recovery for an individual with cancer, and certain foods may need to be avoided to promote health. Soy and soy-based products and their effects on cancer have been the subject of many studies, with conflicting results. More exploration needs to be done. If you have cancer or have had cancer, talk with your doctor before adding soy-based foods to your diet.
Soy and Soy-Based Foods
Soy, a plant that is part of the pea family; has been used for food in Asia for at least 5,000 years, states MayoClinic.com. Use of this plant in other countries began in the 1700s, and soy products are widely used today in the United States. Soy-based foods include soy sauce, tempeh and tofu. The nutrient can also be combined with other ingredients to make soy ice cream, soy flour and vegetarian meat replacements. According to MayoClinic.com, soy is a source of protein, fiber and isoflavones. Isoflavones are plant-based chemicals that may act like estrogen in the human body.
Soy and Breast Cancer
The effect of soy-based foods on breast cancer has been widely studied and has been the subject of much debate. Due to the estrogenlike effects of soy isoflavones, it has been thought that individuals with hormone-sensitive cancers like estrogen-receptor positive breast cancer should stay away from soy, to prevent tumor growth. Studies on this topic have yielded a variety of results, and more research needs to be done to provide a definitive answer. A 2010 study by YA Cho and colleagues, published in the "European Journal of Clinical Nutrition," found that soy intake in post-menopausal women helped reduce the risk of breast cancer. Any woman who is taking hormone therapy for breast cancer should talk with her doctors about whether it is appropriate for her to eat soy foods.
Soy and Other Cancers
Soy may be beneficial for individuals with other types of cancer, and those looking to reduce the risk of developing cancer. Genistein, a soy isoflavone, has been shown to have anti-cancer effects on colon cancer cells, but this is still being studied. A 2011 study by W Qi and associates, published in "BioMed Central Cancer," found that genistein helped inhibit colon cancer cell growth, and may be helpful along with other colon cancer drugs. Individuals with prostate cancer may need to avoid soy products. Genistein actually promoted prostate cancer metastasis in rats, in a 2011 study done by a team led by H Nakamura, published in the "Public Library of Science 1." If you have prostate cancer, talk with your oncologist about whether or not soy-based products are safe for you to consume.
Considerations
If you have cancer, talk with your treatment team about your nutrition plan and whether soy-based products are appropriate for you. There are conflicting opinions on the topic, and your doctors and nutritionists can provide you with detailed information about your situation and how soy may affect your health.
References
- MayoClinic.com; Soy (Glycine Max); Natural Standard Patient Monograph; April 2011
- Breastcancer.org; Soy; February 2011
- PubMed.gov; "European Journal of Clinical Nutrition"; Effect of Dietary Soy Intake on Breast Cancer Risk According to Menopausal and Hormone Receptor Status; YA Cho et al; 2010
- PubMed.gov; "BioMed Central Cancer"; Genistein Inhibits Proliferation of Colon Cancer Cells by Attenuating a Negative Effect of Epidermal Growth Factor on Tumor Suppressor FOXO3 activity; W Qi et al; 2011
- PubMed.gov; "Public Library of Science 1"; Genistein Increases Epidermal Growth Factor Receptor Signaling and Promotes Tumor Progression in Advanced Human Prostate Cancer; H Nakamura et al; 2011
