Coffee brewed from capsule machines may contain estrogenic chemicals (or EDCs, endocrine disrupting chemicals) migrated from plastic. These are chemicals that mimic hormones in the human body. Bisphenol A, bisphenol F, benzophenone, 4-nonylphenol, dibutyl phthalate, and dimethyl terephthalate were detected in capsule coffee. See a summary of the study here.