As the general advice for women with endometriosis seems to be to stay away from dairy (read: The Truth About Dairy), some of us may have turned to soy as a dairy substitute. I did the same until I found out that soy could perhaps not be the best product to use for women with endometriosis either.
The information on the relationship between soy and endometriosis can sometimes be confusing. Soy, for one, is generally problematic: it is known to work wonders for the heart, but may increase the risk of breast cancer. With endometriosis, in particular, opinions are equally split; some experts say dietary phytoestrogens found in soy may increase the risk of the disease by increasing estrogen production in the uterus. The other camp maintains an opposite opinion, claiming soy compounds decrease estrogen, therefore, decreasing the spread of abnormal endometrial tissue.
There is limited data to make a confident judgment on soy and its influence on endometriosis, but it is more common to hear experts urge the removal of soy products from the diet of anyone with the symptoms of endometriosis. The best bet is to stay in the loop on the current evidence in research and talk with professionals in the field.