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Is Turmeric Safe to Eat for People with Hormone-Sensitive Cancers?

Updated: 3 days ago


Turmeric root and turmeric powder contain naturally occurring phytoestrogens.

Is Turmeric Safe to Eat if You Have a Hormone-Sensitive Cancer?


You may have read that turmeric can influence oestrogen signalling, or that it behaves in an oestrogen-like way in the body. If you are living with a hormone-sensitive cancer, that can understandably feel concerning.


Turmeric contains curcumin, a compound studied for its anti-inflammatory and antioxidant properties. In laboratory models, curcumin has shown very weak interaction with oestrogen receptors at high concentrations. Because plant compounds that interact with these receptors are often described as phytoestrogens, curcumin is sometimes talked about in that way too.


So what does this actually mean in real life, at food levels?


Let’s look at what the evidence shows, and whether culinary turmeric has a place in your diet.


The Evidence in Brief: Is Culinary Turmeric Safe?


If you’re short on time, here’s what the research shows:

  • Culinary turmeric used in normal dietary amounts is considered safe for people with hormone-sensitive cancers.

  • There is no human evidence that turmeric used as a spice increases cancer risk or interferes with Tamoxifen.

  • Laboratory findings often cited online involve concentrations far beyond those reached through food and do not reflect real-world dietary use.

  • High-dose curcumin supplements deliver concentrated amounts and should be considered carefully alongside your medications, treatment, and individual health circumstances.


Understanding Turmeric and Curcumin


Turmeric is a bright yellow spice commonly used in cooking, especially in Indian and Southeast Asian cuisines. It comes from the root of the turmeric plant and has a warm, bitter taste. Turmeric contains curcumin, which is its main active component. Curcumin has been widely studied for its potential health benefits, most notably its anti-inflammatory and antioxidant properties.


The amount of curcumin in turmeric root is relatively low (typically less than 5%), and it is poorly absorbed in the gut (1). For this reason, supplements with high concentrations of curcumin are often used to study its effects and much of the research on the health benefits of turmeric have focused on curcumin supplements.


Turmeric, Curcumin and Cancer: What the Research Shows


As a compound with anti-inflammatory and antioxidant properties, curcumin may help support overall health when living with cancer, as well as managing some symptoms, and treatment related side effects.


Research compiling large amounts of data to analyse the effects on inflammation in the body, from a wide range of foods and nutrients, shows that turmeric has one of the strongest anti-inflammatory effects (2). While this is of interest, it is important to note that we see the greatest health gains in whole dietary patterns, where the diet contains a diverse and abundant range of ‘anti-inflammatory’ plant foods (3). Therefore, consuming turmeric alongside other plant foods, herbs and spices is more likely to be beneficial rather than focusing on turmeric in isolation.


Human clinical trials using curcumin supplements have shown mixed findings on its ability to successfully reduce inflammation in the body (4),(5),(6). The variable results could potentially be because different forms and dosages of curcumin are used in the trials, alongside differences in participants’ health, diet, and lifestyle. Additionally, there are many factors that affect inflammatory processes in the body, and as a result, it is very difficult to isolate and examine the effects of one supplement or one nutrient independently. Our overall diets and lifestyle are key.


Some laboratory studies on cancer cells have shown that curcumin can influence processes involved in cancer growth. In cell models, it has been observed to affect cancer cell survival and proliferation.


These findings have led to clinical research exploring its potential role alongside treatment. Some early trial results have generated interest, but larger, well-designed human studies are needed. At present, there is no clear evidence that turmeric or curcumin can prevent or treat cancer in people (Cancer Research UK).


What Are Phytoestrogens and How Do They Relate to Hormone-Sensitive Cancers?


Phytoestrogens are compounds that occur naturally in a wide range of plant foods, including several wholegrains, legumes, seeds, apples, red grapes, citrus fruits, berries, cruciferous vegetables, herbs, spices, and tea (7). Phytoestrogens have a similar structure to our own body’s oestrogen and can bind to the same receptors that our own oestrogen does.


Anything purported to ‘mimic oestrogen’ is understandably concerning with regards to hormone-sensitive cancers. However, evidence shows that phytoestrogens and oestrogen are not as similar as their name suggests.

Laboratory studies looking at different phytoestrogens (8) have shown that there are a variety of ways phytoestrogens can interact with oestrogen and its mechanisms in the body; the majority of which appear to be protective for hormone-sensitive cancers. For example, as phytoestrogens are less potent than the hormone oestrogen, when they attach to oestrogen receptors on our cells, they can render the receptors unavailable to oestrogen, producing a weaker overall effect.


Nevertheless, it is important to note that laboratory studies look at single mechanisms between isolated phytoestrogen compounds at very high doses. This is not directly comparable to the many different mechanisms and compounds acting together from whole foods in the human body. Therefore, to ascertain the actual health effects of these compounds we need to look to human evidence.

Phytoestrogens are abundant in plants and only a plant-free diet would eliminate exposure to them. A cornerstone of global dietary recommendations for cancer prevention, and for risk-reduction following a cancer diagnosis, is to ‘make whole-grains, vegetables, fruit, and pulses such as beans and lentils a major part of the usual daily diet’ (9). When looking at observational studies in large populations, plant foods are associated with either beneficial or neutral outcomes in cancer, including hormone-sensitive cancers (10),(11),(12).


Of all dietary phytoestrogens, soy has the most human evidence available currently. Combining results from many different studies (a meta-analysis) shows this food may be protective in cancer both pre- and post-diagnosis (13),(14),(15). In studies that examined hormone responsive cancers specifically, the worst-case scenario was that soy had no effect on cancer outcomes, either positive or negative. Importantly, it did not increase risk.


Lab studies show that some compounds in soy may be protective in isolation, while others may be problematic. Yet when they are looked at in whole foods (such as edamame beans, tofu, and tempeh) as part of a varied diet, the overall effect is neutral or beneficial. This is likely due to the balanced, synergistic effect of soy’s several phytoestrogens and other beneficial nutrients. It’s a good example of phytoestrogens being a friend and not a foe when it comes to oestrogen and cancer.


“Current evidence suggests that a diet containing naturally occurring phytoestrogens is safe if you’ve had breast cancer and may be beneficial”


What Does Research Say About Turmeric and Its Oestrogenic Effects?


As with many plant compounds that influence hormone signalling, most studies on turmeric (curcumin) have been performed in laboratory cell experiments and in rodents. The studies typically examine isolated compounds, and look at one specific mechanism, at supplemental doses (e.g. 3000mg per day). This is far beyond the amounts we consume by simply adding turmeric as a culinary spice. Therefore, any protective or detrimental effect inferred in these studies is not relevant to looking at food sources in real diets, in real people. However, we can combine findings from laboratory studies with human evidence to gain an overall understanding of its potential effects.


  • Laboratory studies

A 2010 laboratory cell study found that curcumin showed very weak oestrogen-related activity (16). This was at 100nm blood concentrations, which is unachievable from food-based consumption. 100nm curcumin is far beyond concentrations seen in human studies from diet alone, including in blood analysis of Asian populations with high dietary intakes of turmeric (17). Even at these high concentrations, the study showed curcumin had significantly weaker effects than the hormone oestrogen and had no significant effect on any genetic mechanism influenced by oestrogen (16).


Other laboratory studies have used even higher concentrations of curcumin to explore its effects at these doses (18),(19),(20). Overall, these laboratory studies report very mild effects on oestrogen signalling. When curcumin interacts with oestrogen receptors in these experimental models, its activity is far weaker than the body’s own oestrogen. In some cell studies, this has been associated with a reduced rather than increased oestrogen-driven response. Importantly, these findings are confined to laboratory settings and do not indicate clinically meaningful oestrogen stimulation in humans.


In laboratory models, curcumin has also been associated with effects that could be considered protective in the context of hormone-sensitive cancers, including increased cancer cell death (apoptosis) and reduced signals involved in tumour growth and spread. However, these findings remain pre-clinical and cannot be assumed to translate directly into human benefit.


  • Human studies

Observational studies have shown that incidence rates of hormone-sensitive cancers are generally higher in Western populations compared to Asian populations (21). This variation in incidence is influenced by multiple factors, including dietary factors. Spices, such as turmeric, are a key difference in Asian diets compared to Western diets and have been suggested to have cancer-protective properties. Although observational studies can only establish associations and not causation, the lack of supporting trends in such studies for any significantly negative effects of turmeric in overall diets suggests that it does not increase the risk of hormone-sensitive cancers.


While there are no human clinical trials examining turmeric as a potential phytoestrogen, there are a few examining the safety of curcumin at supplemental doses, including in people with hormone-sensitive cancers. One trial showed improved responsiveness to cancer treatment when combined with supplemental curcumin – including separate analysis in oestrogen responsive subtypes (22). No serious adverse effects or safety issues were identified, and no progression or survival outcomes were worse in those who received supplemental curcumin.


In prostate cancer sensitive to the hormone testosterone, a supplement containing curcumin produced improvements in PSA levels, with no adverse effects compared to the placebo group (23).


While a few studies are not sufficient to draw firm conclusions, combined with existing observational evidence, these studies give a good indication there is no problematic oestrogenic effect from curcumin in turmeric, even at supplemental doses, never mind from low food source quantities.


Please note taking curcumin supplements while undergoing cancer treatment is not recommended without consultation with your Oncologist or Oncology Pharmacist. Curcumin supplements may alter the effect of chemotherapy and cancer treatment drugs. High dose curcumin supplements can also have anticoagulant or antiplatelet (blood thinning) effects, as well as inhibiting iron absorption.


Tamoxifen and Turmeric: Food vs Supplements


There is no evidence that food source phytoestrogens consumed as part of a balanced diet have any negative impact on Tamoxifen’s actions and effectiveness. Interestingly, the available evidence suggests the opposite may be true. For example, soy-based phytoestrogens have been shown in laboratory studies to enhance Tamoxifen’s effectiveness. (24),(25). This is supported by a large analysis of human trials on soy foods and breast cancer, where no negative outcomes or safety issues were observed, including in a significant proportion of participants taking Tamoxifen (26).


For those taking Tamoxifen it is important to note that the liver plays a key role in converting it into its active form. Turmeric in supplemental form can affect how well the liver performs this conversion, which could mean that the effects of the Tamoxifen are lost or weakened.


Supplementing with turmeric as opposed to dietary intake through food is not recommended if taking Tamoxifen.


Conclusion: Is Turmeric Safe for People with Hormone-Sensitive Cancers?


Despite understandable concern about plant compounds that may interact with oestrogen pathways, when we combine laboratory, clinical and population-level evidence, there is no indication that culinary turmeric poses harm when used in normal dietary amounts.


This position is consistent with guidance from leading cancer organisations including Cancer Research UK, the Mayo Clinic and Memorial Sloan Kettering.


Research continues to explore whether curcumin supplements may have a role alongside certain cancer treatments. We are still learning more about their safety and effectiveness in those settings.


Written by


Meredy Birdi

BSc (Hons) Dietetics, DipNT, mBDA, mBANT

HCPC registered, CNHC registered


Kim Wilcox

Registered Associate Nutritionist

MSc, ANutr

UKVRN registered


I would like to acknowledge the following individuals for their valuable contributions to the creation of this article:


Dr Catherine Zollman BA Physiol (Oxon), MBBS, MRCP, MRCGP, Fellowship in Integrative Medicine (University of Arizona), Committee member of College of Medicine, BSIO, SIO Medical Lead, Penny Brohn UK


Deborah Grayson BSc Pharm, DipNT, rGPHc, mBant

Pharmacist and Nutritional Therapist


Dr Penny Kechagioglou MBBS, MRCP, CCT (Clin Onc), MPH, MBA, DBA, FMLM, AFMCP

Co-Chair of British Society of Integrative Oncology (BSIO)

Consultant Clinical Oncologist, Chief Clinical Information Officer, and Deputy Chief Medical Officer at the University Hospitals Coventry and Warwickshire


Dr Carol A Granger DProf, MSc, MRSB CBiol, FBANT

Registered Nutrition Practitioner, Director at British Society for Integrative Oncology (BSIO)


 

The content provided in this blog is for informational purposes only and should not be considered personalised nutrition, dietetic, or medical advice. Please consult your healthcare team for personalised advice and guidance regarding your specific medical condition or dietary needs.



References

1. Mahale, J., Singh, R., Howells, L. M., Britton, R. G., Khan, S. M., & Brown, K. (2018, July 10). Detection of Plasma Curcuminoids from Dietary Intake of Turmeric-Containing Food in Human Volunteers. Molecular Nutrition & Food Research, 62(16), 1800267. https://doi.org/10.1002/mnfr.201800267


2. James R Hébert, Nitin Shivappa, Michael D Wirth, James R Hussey, Thomas G Hurley, Perspective: The Dietary Inflammatory Index (DII)—Lessons Learned, Improvements Made, and Future Directions, Advances in Nutrition, Volume 10, Issue 2, March 2019, Pages 185–195, https://doi.org/10.1093/advances/nmy071



4. Jessica J A Ferguson, Kylie A Abbott, Manohar L Garg, Anti-inflammatory effects of oral supplementation with curcumin: a systematic review and meta-analysis of randomized controlled trials, Nutrition Reviews, Volume 79, Issue 9, September 2021, Pages 1043–1066, https://doi.org/10.1093/nutrit/nuaa114




7. Zamora-Ros, R., Knaze, V., Luján-Barroso, L. et al. Dietary intakes and food sources of phytoestrogens in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24-hour dietary recall cohort. Eur J Clin Nutr 66, 932–941 (2012). https://doi.org/10.1038/ejcn.2012.36


8. Wang, X.; Ha, D.; Yoshitake, R.; Chan, Y.S.; Sadava, D.; Chen, S. Exploring the Biological Activity and Mechanism of Xenoestrogens and Phytoestrogens in Cancers: Emerging Methods and Concepts. Int. J. Mol. Sci. 2021, 22, 8798. https://doi.org/10.3390/ijms22168798


9. Basing your diet on plant foods is a great first step to eating well. (n.d.). World Cancer Research Fund. https://www.wcrf-uk.org/preventing-cancer/our-cancer-prevention-recommendations/enjoy-more-grains-veg-fruit-and-beans/



11. Kathryn E Bradbury, Paul N Appleby, Timothy J Key, Fruit, vegetable, and fiber intake in relation to cancer risk: findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)1,2,3,4, The American Journal of Clinical Nutrition, Volume 100, Supplement 1, 2014, Pages S394-S398, ISSN 0002-9165, https://doi.org/10.3945/ajcn.113.071357.





15. Agnieszka Micek, Justyna Godos, Tomasz Brzostek, Agnieszka Gniadek, Claudia Favari, Pedro Mena, Massimo Libra, Daniele Del Rio, Fabio Galvano, Giuseppe Grosso, Dietary phytoestrogens and biomarkers of their intake in relation to cancer survival and recurrence: a comprehensive systematic review with meta-analysis, Nutrition Reviews, Volume 79, Issue 1, January 2021, Pages 42–65, https://doi.org/10.1093/nutrit/nuaa043




18. Kelly Hallman, Katie Aleck, Brigitte Dwyer, Victoria Lloyd, Meghan Quigley, Nada Sitto, Amy E Siebert & Sumi Dinda (2017) The effects of turmeric (curcumin) on tumor suppressor protein (p53) and estrogen receptor (ERα) in breast cancer cells, Breast Cancer: Targets and Therapy, 9:, 153-161, DOI: 10.2147/BCTT.S125783


19. Singh, M., Singh, N. Curcumin counteracts the proliferative effect of estradiol and induces apoptosis in cervical cancer cells. Mol Cell Biochem 347, 1–11 (2011). https://doi.org/10.1007/s11010-010-0606-3




22. Tatul Saghatelyan, Armen Tananyan, Naira Janoyan, Anna Tadevosyan, Hasmik Petrosyan, Araxia Hovhannisyan, Lidia Hayrapetyan, Mikael Arustamyan, Jürgen Arnhold, Andre-Robert Rotmann, Areg Hovhannisyan, Alexander Panossian. Efficacy and safety of curcumin in combination with paclitaxel in patients with advanced, metastatic breast cancer: A comparative, randomized, double-blind, placebo-controlled clinical trial, Phytomedicine, Volume 70, 2020, 153218, ISSN 0944-7113, https://doi.org/10.1016/j.phymed.2020.153218.











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