Genistein / Soy
Also known by these names
Soy foods may have several other labels:
The beans of the soy plant contain isoflavones, a type of phytoestrogens which are chemical structures similar to the estrogen made in our bodies. However, phytoestrogens are not the same as female estrogens. Soy foods do not contain estrogen.1
Treating the Cancer
Working against cancer growth or spread, improving survival, or working with other treatments or therapies to improve their anticancer action
Evidence is generally favorable but sometimes inconclusive.
Lab and Animal Studies
Managing Side Effects and Promoting Wellness
Managing or relieving side effects or symptoms, reducing treatment toxicity, supporting quality of life or promoting general well-being
Reducing the risk of developing cancer or the risk of recurrence
Soy consumption is associated with reduced risk of some cancers but increased risk of others.
Lab and Animal Evidence
Soybeans and foods derived from soybeans are widely available. Extracts are sold as dietary supplements.
While in the past patients on tamoxifen were advised to avoid soy and genistein, more recent data suggest that soy does not reduce effects of tamoxifen and may even protect against estrogen-related endometrial cancers.
Soy foods are generally well tolerated by patient. Interactions with a few prescription medications are noted.31
“Regular ingestion of moderate amounts of soy daily seems to be safe—especially with the traditional fermented soy foods such as miso, tempeh, and natto when made from organic non-GMO soybeans."32
BCCT does not recommend therapies or doses, but provides information for patients and providers to consider as part of a complete treatment plan. Patients should discuss therapies with their physicians, as contraindications, interactions and side effects must be evaluated. Levels of active ingredients of natural products can vary widely between and even within products. See Quality and Sources of Herbs, Supplements and Other Natural Products.
Dosage recommendations are available from these sources:
- Natural Medicines Database (requires purchase)
- Protocols (below) may include specific recommended doses.
Integrative Programs, Protocols and Medical Systems
|For more information about programs and protocols, see our Integrative Programs and Protocols page.|
- Programs and protocols
- Ovarian cancer
- Prostate cancer
- Primary bone cancer (such as osteosarcoma)
- Uterine cancer
- Alschuler & Gazella complementary approaches36
- Block program, , with reference to prostate cancer37
- Chang strategies, , with reference to prostate cancer38
- McKinney protocols39
- General cancer
- Breast cancer
- Ovarian cancer
- Prostate cancer
- Traditional systems
Non-cancer Uses of Soy/Genistein
BCCT has not reviewed the effectiveness of this therapy for non-cancer uses.
Written by Laura Pole, RN, MSN, OCNS, and Nancy Hepp, MS; most recent update April 6, 2019. This summary draws from the Memorial Sloan Kettering Cancer Center’s About Herbs and National Cancer Institute’s PDQ® websites, the American Institute for Cancer Research website, and other sources as noted.
- American Institute for Cancer Research website. Soy and Cancer Survivorship
- National Cancer Institute: Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®)–Health Professional Version: Soy
- Memorial Sloan Kettering Cancer Center About Herbs webpage: Soy
- Academy of Nutrition and Dietetics Oncology Nutrition Dietetic Practice Group: Soy and Breast Cancer
- Moss Reports (purchase required): Select from the list of cancers down the left side of the page for a report describing uses of conventional, complementary, alternative and integrative therapies related to that cancer. Ralph Moss is among the most knowledgeable and balanced researchers of integrative cancer therapies. The cost of his Moss Reports is not negligible, but many patients find them of considerable value. Moss is also available for consultations.
- Lorenzo Cohen and Alison Jefferies: Anticancer Living: Transform Your Life and Health with the Mix of Six
- National Cancer Institute: Complementary and Alternative Medicine for Health Professionals
- Keith I. Block, MD: Life over Cancer: The Block Center Program for Integrative Cancer Treatment
- Lise Alschuler, ND, FABNO, and Karolyn Gazella: The Definitive Guide to Cancer, 3rd Edition
- American Botanical Council: HerbMed
- Lone Star Medical Group: Natural Alternative Treatments
- Therapeutic Research Center: Natural Medicines Database
- National Cancer Institute: Office of Cancer Complementary and Alternative Medicine
- The Tracey Birnhak Nutritional Counseling Services: Soy and Breast Cancer
- Neil McKinney, BSc, ND: Naturopathic Oncology, 3rd Edition
- Donald I. Abrams, MD, and Andrew T. Weil, MD: Integrative Oncology, 2nd Edition
- Raymond Chang, MD: Beyond the Magic Bullet: The Anti-Cancer Cocktail
- National Cancer Institute at the National Institutes of Health: PDQ® Cancer Information Summaries
- Dwight McKee, MD, editor: Clinical Pearls
- Keith Block and others: A Broad-Spectrum Integrative Design for Cancer Prevention and Therapy
- Barbara MacDonald, ND, LAc: The Breast Cancer Companion: A Complementary Care Manual: Third Edition