Limit or avoid during tamoxifen treatment - foods

Last updated: August 14, 2025

Foods to limit while on tamoxifen

The current webpage is designed to make additional research available concerning how certain foods and beverages or their major bioactive components can interfere with or reduce the beneficial treatment effects of tamoxifen. At the bottom of this webpage are links to studies relating to the foods under limit or avoid in Foods to eat and avoid during tamoxifen treatment.

Foods and beverages can reduce the beneficial cytotoxic effects of tamoxifen, worsen its harmful side effects, or otherwise interfere with treatment due to a variety of factors, among them:

Contains ethanol (beer, liquor, wine)
Potential cytochrome P450 interactions (açaí berries, grapefruit, limes, pomelos)
High genistein content (soy protein isolate, soybean paste, soybeans)
High omega-6 culinary oils (corn oil, safflower oil, soybean oil, sunflower oil)
Sesame lignans (sesame seeds & sesame seed oil)
High tangeretin content (peels of mandarin oranges (clementines, mandarins, tangerines) and all other orange varieties)

Selected breast cancer studies

CYP2D6 genotype and outcome in tamoxifen treated early breast cancer Cite
Thorén L, Lindh JD, Molden E, Kristiansen Kringen M, Bergh J, Eliasson E, et al. CYP2D6 genotype and outcome in tamoxifen treated early breast cancer. Acta Oncologica. MJS Publishing, Medical Journals Sweden AB; 2025; 64:848-856 10.2340/1651-226x.2025.43208
Polymethoxylated flavonoids in citrus fruits: absorption, metabolism, and anticancer mechanisms against breast cancer Cite
Wang Y, Mou Y, Lu S, Xia Y, Cheng B. Polymethoxylated flavonoids in citrus fruits: absorption, metabolism, and anticancer mechanisms against breast cancer. PeerJ. PeerJ; 2024; 11:e16711 10.7717/peerj.16711
Network Analysis of the Herb–Drug Interactions of Citrus Herbs Inspired by the “Grapefruit Juice Effect” Cite
Lü J, Zhang D, Zhang X, Sa R, Wang X, Wu H, et al. Network Analysis of the Herb–Drug Interactions of Citrus Herbs Inspired by the “Grapefruit Juice Effect”. ACS Omega. American Chemical Society (ACS); 2022; 7:35911-35923 10.1021/acsomega.2c04579
Phenolic and flavonoid content and in vitro inhibitory effect of some Amazonian fruit juices on CYP3A4 activity Cite
COSTA EMA, DE ANDRADE FIGUEIRA MB, CARRÃO DB, HABENSCHUS MD, OLIVEIRA ARMD, ACHO LDR, et al. Phenolic and flavonoid content and in vitro inhibitory effect of some Amazonian fruit juices on CYP3A4 activity. Acta Amazonica. FapUNIFESP (SciELO); 2022; 52:172-178 10.1590/1809-4392202103642
Tangeretin as an adjuvant and chemotherapeutic sensitizer against various types of cancers: a comparative overview Cite
Alhamad DW, Elgendy SM, Al-Tel TH, Omar HA. Tangeretin as an adjuvant and chemotherapeutic sensitizer against various types of cancers: a comparative overview. Journal of Pharmacy and Pharmacology. Oxford University Press (OUP); 2021; 73:601-610 10.1093/jpp/rgab013
Association of CYP2D6 genotype and tamoxifen metabolites with breast cancer recurrence in a low-dose trial Cite
DeCensi A, Johansson H, Helland T, Puntoni M, Macis D, Aristarco V, et al. Association of CYP2D6 genotype and tamoxifen metabolites with breast cancer recurrence in a low-dose trial. npj Breast Cancer. Springer Science and Business Media LLC; 2021; 7 10.1038/s41523-021-00236-6
Bioinformatic analysis reveals the molecular targets of tangeretin in overcoming the resistance of breast cancer to tamoxifen Cite
Hermawan A, Putri H, Ikawati M. Bioinformatic analysis reveals the molecular targets of tangeretin in overcoming the resistance of breast cancer to tamoxifen. Gene Reports. Elsevier BV; 2020; 21:100884 10.1016/j.genrep.2020.100884
Effect of isoflavones on breast cancer cell development and their impact on breast cancer treatments Cite
Hatono M, Ikeda H, Suzuki Y, Kajiwara Y, Kawada K, Tsukioki T, et al. Effect of isoflavones on breast cancer cell development and their impact on breast cancer treatments. Breast Cancer Research and Treatment. Springer Science and Business Media LLC; 2020; 10.1007/s10549-020-05957-z
Screening for CYP3A4 inhibition and induction coupled to parallel artificial membrane permeability assay (PAMPA) for prediction of botanical-drug interactions: The case of açaí and maca Cite
Zhang Y, Rants'o TA, Jung D, Lopez E, Abbott K, Pondugula SR, et al. Screening for CYP3A4 inhibition and induction coupled to parallel artificial membrane permeability assay (PAMPA) for prediction of botanical-drug interactions: The case of açaí and maca. Phytomedicine. Elsevier BV; 2019; 59:152915 10.1016/j.phymed.2019.152915
Combinatorial anti-proliferative effects of tamoxifen and naringenin: The role of four estrogen receptor subtypes Cite
Xu Z, Huang B, Liu J, Wu X, Luo N, Wang X, et al. Combinatorial anti-proliferative effects of tamoxifen and naringenin: The role of four estrogen receptor subtypes. Toxicology. Elsevier BV; 2018; 410:231-246 10.1016/j.tox.2018.08.013
Alcohol Regulates Genes that Are Associated with Response to Endocrine Therapy and Attenuates the Actions of Tamoxifen in Breast Cancer Cells Cite
Candelaria NR, Weldon R, Muthusamy S, Nguyen-Vu T, Addanki S, Yoffou P, et al. Alcohol Regulates Genes that Are Associated with Response to Endocrine Therapy and Attenuates the Actions of Tamoxifen in Breast Cancer Cells. PLOS ONE. Public Library of Science (PLoS); 2015; 10:e0145061 10.1371/journal.pone.0145061
Proteomic Changes Induced by Effective Chemopreventive Ratios of n-3:n-6 Fatty Acids and Tamoxifen against MNU-Induced Mammary Cancer in the Rat Cite
Skibinski CG, Thompson HJ, Das A, Manni A, Bortner JD, Stanley A, et al. Proteomic Changes Induced by Effective Chemopreventive Ratios of n-3:n-6 Fatty Acids and Tamoxifen against MNU-Induced Mammary Cancer in the Rat. Cancer Prevention Research. American Association for Cancer Research (AACR); 2013; 6:979-988 10.1158/1940-6207.capr-13-0152
Omega-3 Fatty Acids for Prevention of Breast Cancer: an Update and the State of the Science Cite
Iyengar NM, Hudis CA, Gucalp A. Omega-3 Fatty Acids for Prevention of Breast Cancer: an Update and the State of the Science. Current Breast Cancer Reports. Springer Science and Business Media LLC; 2013; 5:247-254 10.1007/s12609-013-0112-1
Low-dose dietary genistein negates the therapeutic effect of tamoxifen in athymic nude mice Cite
Du M, Yang X, Hartman JA, Cooke PS, Doerge DR, Ju YH, et al. Low-dose dietary genistein negates the therapeutic effect of tamoxifen in athymic nude mice. Carcinogenesis. Oxford University Press (OUP); 2012; 33:895-901 10.1093/carcin/bgs017
Reduced Bioavailability of Tamoxifen and its Metabolite 4-Hydroxytamoxifen After Oral Administration with Biochanin A (an Isoflavone) in Rats Cite
Singh SP, Wahajuddin , Raju KSR, Ali MM, Kohli K, Jain GK. Reduced Bioavailability of Tamoxifen and its Metabolite 4-Hydroxytamoxifen After Oral Administration with Biochanin A (an Isoflavone) in Rats. Phytotherapy Research. Wiley; 2011; 26:303-307 10.1002/ptr.3652
Abstract 5578: Transcriptomic changes in tamoxifen-treated mammary tumors in Sprague-Dawley rats fed with omega-3 or omega-6 rich diets Cite
Bidinotto LT, Vanegas JE, Vanden Heuvel JP, de Cicco RL, Santucci-Pereira J, Washington S, et al. Abstract 5578: Transcriptomic changes in tamoxifen-treated mammary tumors in Sprague-Dawley rats fed with omega-3 or omega-6 rich diets. Prevention Research. American Association for Cancer Research; 2011; 10.1158/1538-7445.am2011-5578
Significant Effect of Polymorphisms inCYP2D6andABCC2on Clinical Outcomes of Adjuvant Tamoxifen Therapy for Breast Cancer Patients Cite
Kiyotani K, Mushiroda T, Imamura CK, Hosono N, Tsunoda T, Kubo M, et al. Significant Effect of Polymorphisms inCYP2D6andABCC2on Clinical Outcomes of Adjuvant Tamoxifen Therapy for Breast Cancer Patients. Journal of Clinical Oncology. American Society of Clinical Oncology (ASCO); 2010; 28:1287-1293 10.1200/jco.2009.25.7246
Association between Alcohol Intake and Serum Sex Hormones and Peptides Differs by Tamoxifen Use in Breast Cancer Survivors Cite
Wayne S, Neuhouser ML, Ulrich CM, Koprowski C, Wiggins C, Baumgartner KB, et al. Association between Alcohol Intake and Serum Sex Hormones and Peptides Differs by Tamoxifen Use in Breast Cancer Survivors. Cancer Epidemiology Biomarkers & Prevention. American Association for Cancer Research (AACR); 2008; 17:3224-3232 10.1158/1055-9965.epi-08-0171
Phytoestrogens and breast cancer: a complex story Cite
Helferich WG, Andrade JE, Hoagland MS. Phytoestrogens and breast cancer: a complex story. Inflammopharmacology. Springer Science and Business Media LLC; 2008; 16:219-226 10.1007/s10787-008-8020-0
Lignan-rich sesame seed negates the tumor-inhibitory effect of tamoxifen but maintains bone health in a postmenopausal athymic mouse model with estrogen-responsive breast tumors Cite
Sacco SM, Chen J, Power KA, Ward WE, Thompson LU. Lignan-rich sesame seed negates the tumor-inhibitory effect of tamoxifen but maintains bone health in a postmenopausal athymic mouse model with estrogen-responsive breast tumors. Menopause. Ovid Technologies (Wolters Kluwer Health); 2008; 15:171-179 10.1097/gme.0b013e3180479901
The Effect of the Phytoestrogens Genistein, Daidzein, and Equol on the Growth of Tamoxifen-Resistant T47D/PKCα Cite
Tonetti DA, Zhang Y, Zhao H, Lim S, Constantinou AI. The Effect of the Phytoestrogens Genistein, Daidzein, and Equol on the Growth of Tamoxifen-Resistant T47D/PKCα. Nutrition and Cancer. Informa UK Limited; 2007; 58:222-229 10.1080/01635580701328545
Stimulatory effect of genistein and apigenin on the growth of breast cancer cells correlates with their ability to activate ER alpha Cite
Seo H, DeNardo DG, Jacquot Y, Laïos I, Vidal DS, Zambrana CR, et al. Stimulatory effect of genistein and apigenin on the growth of breast cancer cells correlates with their ability to activate ER alpha. Breast Cancer Research and Treatment. Springer Science and Business Media LLC; 2006; 99:121-134 10.1007/s10549-006-9191-2
Bergamottin, lime juice, and red wine as inhibitors of cytochrome P450 3a4 activity: comparison with grapefruit juice Cite
Bailey D. Bergamottin, lime juice, and red wine as inhibitors of cytochrome P450 3a4 activity: comparison with grapefruit juice. Clinical Pharmacology & Therapeutics. Wiley; 2003; 73:529-537 10.1016/s0009-9236(03)00051-1
Influence of Tangeretin on Tamoxifen's Therapeutic Benefit in Mammary Cancer Cite
Bracke ME, Depypere HT, Boterberg T, Van Marck VL, Vennekens KM, Vanluchene E, et al. Influence of Tangeretin on Tamoxifen's Therapeutic Benefit in Mammary Cancer. JNCI Journal of the National Cancer Institute. Oxford University Press (OUP); 1998; 91:354-359 10.1093/jnci/91.4.354

Selected breast cancer studies

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