  We propose a simple prescription for including low-energy weak-interactions
into the framework of holographic QCD, based on the standard AdS/CFT dictionary
of double-trace deformations. As our proposal enables us to calculate various
electro-weak observables involving strongly coupled QCD, it opens a new
perspective on phenomenological applications of holographic QCD. We illustrate
efficiency and usefulness of our method by performing a few exemplar
calculations; neutron beta decay, charged pion weak decay, and meson-nucleon
parity non-conserving (PNC) couplings. The idea is general enough to be
implemented in both Sakai-Sugimoto as well as Hard/Soft Wall models.
