It sometimes seems to be unclear for some why soy should be omitted from the diet when you have endometriosis. In principle soy products will upset your natural hormone balance because soy contains high levels of phytoestrogens which will mimic our own estrogen hormones.
Having some phytoestrogens in our diet can be beneficial as they are thought to block our estrogen receptors and help to reduce excess estrogens from circulating in our system. But having too many phytoestrogens can tip the balance.
But the problem with soy goes beyond the issue of phytoestrogens. Soy can cause many negative health problems which seems to be worse for those with endometriosis.
Some of these problems include:
Many who change their old diet for a diet to control endometriosis will sometimes be replacing the dairy and protein foods and substituting them with soy products. These can include soy milk, soy spreads, soy cheeses, soy-based burgers and substitute meats, and many other alternative soy products. You need to avoid all modern soy-based foods and food substitutes.
The only safe soy foods are those that come from eastern traditions of fermented foods like miso, tempeh and tamari. These foods are safe enough for the healthy person, but for women with endometriosis their consumption needs to be minimal because of the high levels of phytoestrogens.
Here are some feedback comments from women with endometriosis and their experiences of using soy:
‘I had a very late diagnosis of endometriosis after having pain for 20 years. At the age of 46 I had a laparoscopy which confirmed endo and the surgeon used diathermy to burn a lot of the plaques off of my ovaries, fallopian tubes and uterus. Within 4 days of the surgery I began to have menopause symptoms. After trying HRT and suffering more endo symptoms I decided to stop using it.
I have been post-menopausal for 13 years. Fast forward to this January when I decided to use a Soya meal replacement diet. Within 3 months my previously dormant fibrocystic breast disease returned (diagnosed on a routine mammogram) and I now have pelvic pain which feels just like the endo which has been dormant through the last 12 years. I also managed to have a recurrence of hashimotos thyroid symptoms which had also been under control for the last 10 years.’
‘I was just reflecting on whether or not soy had triggered my Endo when I came upon this post. In my early 20s I took to having daily soy protein shakes to lose weight and while it did help with the weight loss my Endo symptoms truly began around this time. I have only recently started to learn about the links to soy and estrogen response and now I am almost certain that this was a major contributing factor to my Endo.’
‘Several years ago, a naturopath recommended that I switch to soy and avoid dairy. Within weeks I stopped ovulating and just bled for weeks without relief, I truly believe soy disrupted my hormones and created oestrogen excess – being a PCOS sufferer with mild Endo, I was already battling oestrogen dominance so switching to soy was the worst thing I could have done.’
So you can now see that omitting soy from your diet when you have endometriosis is an important factor to ensure you do not make your symptoms worse. There are plenty of other alternatives to getting sufficient protein in your diet if you are reducing your intake of animal-based proteins which you can read about HERE.
Zhong XS, et al. Association between Dietary Isoflavones in Soy and Legumes and Endometrial Cancer: A Systematic Review and Meta-Analysis. J Acad Nutr Diet. 2018;118(4):637-651.
suchiya M, et al. Effect of soy isoflavones on endometriosis: interaction with estrogen receptor 2 gene polymorphism. Epidemiology. 2007;18(3):402-408. https://www.ncbi.nlm.nih.gov/pubmed/17474167. Accessed February 9, 2020.
Upson K, et al. Soy-based infant formula feeding and menstrual pain in a cohort of women aged 23-35 years. Hum Reprod. 2019;34(2):148-154. https://www.ncbi.nlm.nih.gov/pubmed/30412246. Accessed February 9, 2020.
Mvondo MA. Soy Intake Since the Prepubertal Age May Contribute to the Pathogenesis of Endometriosis in Adulthood. Journal of Medicinal Food. 2019;22(6). https://www.liebertpub.com/doi/full/10.1089/jmf.2018.0160. Accessed February 9, 2020
Tsuchiya, M., Miura, T., Hanaoka, T., Iwasaki, M., Sasaki, H., Tanaka, T., … Tsugane, S. (2007). Effect of Soy Isoflavones on Endometriosis. Epidemiology, 18(3), 402–408. doi:10.1097/01.ede.0000257571.01358.f9
Mumford, S. L., Weck, J., Kannan, K., & Buck Louis, G. M. (2017). Urinary Phytoestrogen Concentrations Are Not Associated with Incident Endometriosis in Premenopausal Women. The Journal of nutrition, 147(2), 227–234. doi:10.3945/jn.116.238840