That is a great question! I have often wondered that myself!
I have the worst case of fibrocystic breast cysts that my breast surgeon and my Imaging center radiologists have ever seen. They have named me "cyst queen" and I have to have semi-annual bilateral ultrasounds to monitor the cysts that are not aspirated. I do not drink any caffeine and have eliminated all processed foods yet the cysts continue to form.
Take care!