Though I am ER-, I often see questions related to ER+, Flax and Soy. I follow Diana Dyers Breast Cancer diet (she is a registered dietician who is also a 3 time cancer survivor...2 times w/ breast cancer and my dietician often uses her information as a guide). On her website she specifically answers the questions of ER+, flax and soy so I attached the question answer portion of her website. For soy, refer to breast cancer; for flax, refer to flax. Good luck and good health.
Rhonda Hoffman
PS, I've found that when I have additional questions that if I email her, she is ever so kind to email me back.
http://www.cancerrd.com/faqs.htm